Enhanced detection of HER2 through a layer-by-layer strategy using a TiVC MXenes/Au nanocomposite amplified analytical biosensor for precise cancer biomarker monitoring

Enhanced detection of HER2 through a layer-by-layer strategy using a TiVC MXenes/Au nanocomposite amplified analytical biosensor for precise cancer biomarker monitoring | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Enhanced detection of HER2 through a layer-by-layer strategy using a TiVC MXenes/Au nanocomposite amplified analytical biosensor for precise cancer biomarker monitoring Najmeh Zare, Hassan Karimi-Maleh, Zhouxiang Zhang, Yangpin Wen, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4399330/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Oct, 2024 Read the published version in Advanced Composites and Hybrid Materials → Version 1 posted 11 You are reading this latest preprint version Abstract This research work explores the development and application of layer-by-layer modified electrochemical apta-sensor for the precise monitoring of HER2, a crucial biomarker associated with breast cancer. The surface of the screen-printed carbon electrode was modified with gold nanoparticle (Au-NP) and TiVC MXene catalyst plus Pb 2+ loaded aptamer (SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer), which showed a high selectivity and affinity toward HER2 and offered a sensitive detection platform. The MXene nano-layer was synthesized and characterized by FT-IR, MAP, EDS, and TEM methods and used as a substrate to improve electrochemical conductivity and loading of biological recognition element. The difference of stripping signals of the Pb 2+ from the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer before and after incubation in HER2 solution was selected as analytical response to achieve a reliable and quantitative analysis for HER2 concentrations. The results demonstrate a linear dynamic range of 1.0–1200 pg/mL for monitoring of HER2 with limit of detection of 50 fg/mL. Agood affinity of fabricated aptasensor to HER2 in the presence some other biomarkers such as PR, ER, and CEA confirmed the selectivity of the fabricated biosensor towards HER2. Aptamer HER2 MXene nano-layer Hybrid composite Biosensor Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 1 Introduction Biomarkers application accounts as a powerful and dynamic approach to gain insight into various malignancies. They have a wide range of applications in fields such as analytical epidemiology, randomized clinical trials, screening, diagnosis, and prediction. These biomarkers are used to track changes in tissue constituents or body fluids and provide valuable tools for classifying diseases and risk factors in a consistent manner. In addition, they provide valuable information about the underlying pathogenesis of diseases and expand our knowledge base in this field. Biomarkers are detectable signals detected in biological samples such as blood, urine, or tissue and have a wide range of applications, including disease screening, diagnosis, characterization, and monitoring [ 1 ]. In addition, biological markers play a key role in the development of personalized therapeutic interventions, tailoring treatments to individual patients. They are also valuable in predicting and managing adverse reactions to drugs. Furthermore, biomarkers are utilized in identifying different cell types and conducting pharmacodynamics and dose-response studies. Biomarkers consist of proteins, nucleic acids, hormones, enzymes, and other molecules that are linked to particular biological functions or disease states. Their significance lies in their ability to aid in disease diagnosis, prognosis, treatment monitoring, and prediction of patient outcomes. By measuring and analyzing these biomarkers, healthcare professionals can gain a deeper understanding of the presence, progression and severity of diseases, enabling them to make informed decisions about personalized treatments. The discovery and validation of biomarkers have created a paradigm shift in medicine that facilitates early disease detection, accurate diagnosis, and targeted treatment approaches, ultimately leading to improved patient outcomes and improved healthcare management in general [ 2 ]. Bio-monitoring of cancer biomarkers plays a crucial role in early cancer detection and personalized medicine. Breast cancer can be considered one of the most important cancers, and its measurement can provide valuable assistance in preventing mortality. For this purpose, by measuring the protein level, it is possible to identify one of these proteins, namely HER2, in this context. The HER2 receptor, known as human epidermal growth factor receptor 2, is a type of membrane tyrosine kinase that influences cell proliferation and survival when it is activated. Located on chromosome 17q12, the HER2 oncogene is responsible for the amplification of the HER2 receptor, leading to its overexpression. This amplification is a key driver in the development and progression of certain types of breast cancer. It is estimated that around 15 to 20 percent of breast cancers exhibit HER2 amplification [ 3 ]. The status of HER2 is commonly evaluated using two main methods: immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). IHC measures the expression level of the HER2 protein on the cell membranes, while FISH determines the amplification of the HER2 gene [ 4 , 5 ]. Immunohistochemistry (IHC) is a widely used staining technique that enables the quantitative and qualitative measurement of protein antigens in biological and tissue samples. It involves the binding of specific antibodies to the target antigens, facilitating their detection. Immunohistochemical staining is extensively utilized in histopathology departments for various purposes. In contemporary medical practice, the evaluation of tissue-specific genes using immunohistochemistry plays a crucial role in tumor classification at different stages, thereby aiding in the diagnosis process. In addition, the ISH test, a molecular technique, is utilized to identify the overgrowth of the HER2 gene in cancer cells. This method employs probes labeled with fluorescent markers that selectively bind to the HER2 gene region. The number of HER2 gene copies is detected and the ratio of HER2 gene copies to control gene copies is calculated, which allows determination of HER2 amplification. Various methods have been developed to measure the HER2 protein, and biosensors have emerged as a particularly advantageous approach in this context. Biosensors offer several benefits over traditional laboratory detection methods, including enhanced sensitivity and rapid response, compact size and affordability, and the ability to work with small sample volumes. In addition, continuous advances in bioassays increase the accuracy of detecting normal and elevated levels of tumor biomarkers in patients' biological fluids, such as serum, plasma, whole blood, and urine. While various biomarkers including DNA, RNA, proteins, and cells have been identified, protein detection and detection of circulating tumor cells (CTCs) are the most commonly reported methods. These approaches have been validated as tumor biomarkers by widely recognized expert organizations [ 6 ]. Studies have demonstrated that the utilization of a biosensor employing a layer-by-layer strategy for the effective monitoring of HER2 enhances the accuracy of the assay by increasing the available surface area for binding with the analyte, thereby improving sensitivity. In this platform, the sensor is constructed by sequentially depositing TiVC MXenes and Au NPs on the transducer surface. The TiVC MXenes serve as a conductive matrix for signal amplification, while the gold nanoparticles act as scaffolds for the presentation of HER2-specific antibodies. MXene, a novel class of two-dimensional (2D) metals, has garnered significant attention due to its unique properties. MXenes are derived from the intermediate separation of MAX phases, which are compounds composed of a primary transition metal (such as Ti, V, Sc, Mo, Nb, Cr) from the periodic table, along with aluminum (A) and carbon or nitrogen (X) elements [ 7 ]. These materials exhibit exceptional characteristics, including a large specific surface area, high metal conductivity, hydrophilicity, and low diffusion barriers. TiVC-MXene has a broad range of applications in various fields, including energy [ 8 ], capacitors [ 9 ], electromagnetic interference (EMI) shielding [ 10 ], and biosensors [ 11 , 12 ]. It exhibits versatile properties that make it suitable for these applications. Furthermore, its surface functional groups (-O, -OH, and -F) make MXene nanosheets highly suitable for aptamer immobilization, facilitating the development of aptasensors that have shown promising contributions in recent years [ 13 – 15 ]. Gold (Au) nano/microstructures possess multiple functionalities that make them suitable for specific bonding with biological elements [ 16 , 17 ]. This characteristic results in an increased number of active sites and enhanced catalytic efficiency, leads to significant improvements in the performance of electrochemical sensors. In this study, we developed a label-free electrochemical aptasensor by decorating TiVC-MXene nanosheets with Au nanoparticles (Au NPs) to immobilize the thiolated HER2 aptamer impregnated withPb 2+ ions on the electrode surface. The synthesized TiVC-MXene/Au NPs nanocomposite exhibited a higher number of active sites for the immobilization of the aptamer, improved electrode conductivity, and accelerated the charge transfer. Subsequently, the aptamer specific to HER2 was attached to the surface of the SPCE/TiVC-MXene/Au NPs through covalent bonding between Au NPs and thiolated aptamer. A novel strategy was employed, utilizing the square wave anodic stripping voltammetry (SWASV) response of Pb 2+ ions captured by aptamer as the indicator signal. This allowed for the direct detection of signal changes when Pb 2+ ions leave the electrode surface due to the interaction of HER2 with the aptamer. To the best of our knowledge, this is one of the most efficient electrochemical aptasensors designed to monitor HER2 in real samples applicable for breast cancer diagnosis. 2 Experiment section 2.1 Materials and reagents We acquired Titanium Vanadium Aluminum Carbide (TiVAlC) from Laizhou Kai Kai Ceramic Materials Company, Ltd. located in Shandong, China. The HAuCl 4 ·4H 2 O, 6-Mercaptohexanol (MCH), LiF, Pb(NO 3 ) 2 , Tris(hydroxymethyl)aminomethane (Tris), and Tris(2-carboxyethyl) phosphine hydrochloride (TCEP) were purchased from Adamas (Shanghai Titan Scientific Company, Ltd., China). The substances utilized in this research were of analytical quality and were employed without undergoing any purification procedures. 2.2 TiVC-MXene synthesis TiVC-MXene was synthesized as reported by Yazdanparast et al. [ 18 ]. A solution of 1.9 M LiF in concentrated HCl (approximately 37%) was prepared by adding 1.2 g LiF to 24 mL of HCl solution under ambient condition. Then, 1.0 g of the initial MAX phase was mixed with 12 mL of acidic LiF solution at a temperature of 55 o C for a duration of 60 hr, which removed the Al from the MAX phase via etching process. After etching, the resulting mixture was washed with distilled water and separated into powder and supernatant through centrifugation. The powder was subjected to several washing steps until the pH reached approximately 6.0. Finally, the obtained TiVC-MXene was dried at room temperature. Additionally, another portion of TiVAlC-MAX phase was treated with 50% HF for 24 hr at room temperature to compare its elemental composition with the MXene prepared using the LiF/HCl solution. 2.3 Preparation of the Pb 2+ -aptamer solution and the TiVC-MXene suspension The aptamer specific to HER2 was acquired from Sangon (Shanghai, China) and used for fabrication of the aptasensor with following sequence: 5'-GGGCCGTCGAACACGAGCATGGGCGGGCCTAGGATGACCTGAGTACTGTCC-3'. Stock solutions of the Pb 2+ -aptamer (100 µM) were prepared using Tris–HCl buffer. The Tris–HCl buffer consisted of a 1.0 M KCl solution containing 10 mM Tris, 1.0 mM of TCEP and EDTA, which its pH was adjusted to 8.0 using HCl. The prepared stock solutions were stored in the refrigerator. The mixture containing the TiVC-MXene was diluted. Then, 4.5 µL of 0.4 mM aptamer specific to HER2 was added to the diluted mixture. Afterward, a solution of 5 mM Pb 2+ with a volume of 150 mL was added to the mixture. The entire solution was placed on a shaker and incubated overnight, allowing the reaction to occur. 2.4 Preparation of the TiVC-MXene/Au NPs/Pb 2+ -aptamer–based biosensor Voltammetric measurements were conducted in a 10 mM Tris–HCl buffer (pH = 7.4). Prior to modifying the screen-printed carbon electrode (SPCE), its surface underwent polishing with 0.05 µm alumina slurry being rubbed on the chamois leather until it became smooth and reflective It was then thoroughly cleaned using ultrasonication in double-distilled deionized water, followed by absolute ethanol, and once again in double-distilled deionized water. Afterward, the electrode surface was air-dried. Next, a 5.0 µL suspension of TiVC-MXene (0.5 mg/mL) was drop-cast onto the SPCE surface and dried using an infrared lamp. The modified SPCE was subsequently placed in a solution of 10 mM HAuCl 4 in 0.1 M KCl for electrodeposition at -0.3 V for 50 seconds, and then air-dried. Afterward, a 30 µL solution of the Pb 2+ -aptamer was dropped onto the modified electrode surface and incubated at 4°C for 12 hours. The SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer was then washed with Tris-HCl buffer (10 mM, pH 7.4). To further enhance the sensing performance, 1 mM MCH was applied onto the modified electrode surface for 1 hr at room temperature, followed by rinsing with Tris-HCl buffer (10 mM, pH 7.4). Later, the aptasensor was incubated in a HER2 solution followed by electrochemical measurements were conducted using square wave anodic striping voltammetry (SWASV) in a 10 mM Tris-HCl buffer solution (pH 7.4). The measurements involved a negative potential sweep from 0.2 to -0.8 V. Each measurement was repeated at least three times. 2.5 Procedure of work Scheme 1 illustrates a detailed overview of the step-by-step fabrication method of the aptasensor, which has been developed specifically for the purpose of detecting HER2. In this particular research, an electrochemical aptamer-based sensor was developed for the detection of the HER2 biomarker. The sensor utilized a SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer as its framework. The process involved in biocoding synthesis is as follows: HER2 is fully adsorbed onto the surface of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer due to its interaction with the aptamer. Furthermore, the high surface area of TiVC Maxene can effectively improve conductivity of biosensor and loading of aptamer for biomarker detection. The presence of Au NPs guarantees the high electrical conductivity of the aptasensor and the effective binding of the aptamer to the SPCE/TiVC-MXene surface along with expanding the active surface of the biosensor. In the presence of HER2, aptamers on the capture probe selectively recognize HER2 and bind to it. Therefore, the interaction of Pb 2+ ions with aptamer is weakened. As the result, the Pb 2+ ions are released to the solution and the surface concentration of Pb 2+ ions decreases. Concurrently, the peak current of Pb 2+ in the recorded SWASVs decreases Scheme 1 provides a visual representation of this process. 3 Results and discussions 3.1 Characterization of TiVC-MXene According to Fig. 1 A, the TiVAlC Max phase has a complex and dense layered structure. On the other hand, mapping analysis of TiVAlC Max phase shows the presence of Ti, V, Al, and C elements with good distribution that confirms the high purity of precursor used for TiVC-MXene fabrication. Once the precursor is washed with a LiF/HCl solution and the aluminum layer is removed, the distinct structure of separate layers with visible empty spaces between them becomes apparent (Fig. 1 B). This observation serves as a confirmation of the accurate and suitable synthesis of TiVC-MXene. The mapping analysis reveals that the removal of the aluminum layer has been carried out to the best extent possible, and structure of TiVC-MXene formed with some empty layers as expected. Compared to the thin-layer TEM image of TiVC-MXene (Fig. 2 B), the TEM image of Max phase (Fig. 2 A) exhibits a denser and compact microstructure. The elements analysis images of Max phase and MXene (Fig. 2 C and Fig. 2 D) shows that the aluminum has been successfully removed to the maximum extent possible, leading to the well-established synthesis of MXene with the desired structure. The atomic force microscopy (AFM) image in Fig. 3 A depicts the layered structure of TiVC-MXene, showing distinct layers that confirm the removal of the aluminum layer and the synthesis of TiVC-MXene with the expected thin layer size. Figure 3 B illustrates the 2D configuration of TiVC-MXene, revealing a H4 loop under a type IV isotherm, suggesting the existence of a mesoporous framework. The specific surface area of TiVC-MXene was calculated to be 2.11 m 2 /g. The PSD histogram of TiVC-MXene exhibits an average pore diameter of 33 nm. The X-ray diffraction (XRD) patterns in Fig. 4 reveals the structure characteristics of TiVC-MXene and TiVAlC Max phase. The dominant crystal planes observed in the XRD patterns are (002) and (103), the Max phase peaks showed a substantial reduction in intensity and shift towards positive values after being subjected to etching. These findings strongly indicate the successful completion of the synthesis process that match with reported XRD patterns of TiVC-MXene and utilized Max phase [ 18 ]. The valence bond states and elemental composition of the synthesized TiVAlC and TiVC-MXene were examined by XPS. Figure 5 A displays the XPS full survey spectra of TiAlVC and TiVC − MXene, demonstrating the coexistence of Ti, O, C, F, V and Al elements. Figures 5 B-D exhibit the high-resolution XPS results of C 1s, Ti 2p and O 1s & V 2p, respectively. Figure 5 B shows four peaks for C 1s at 285.1, 284.7, 286.1,and 288.7 eV, which can be assigned to the C-Ti(V), C-C, C = O, and O-C = O [ 1 ]. Figure 5 C depicts six peaks at 455.3, 456.4, 458.7, 461.4, 463.4,and 464.7 eV for Ti 2p, matching with Ti-C 2p 3/2 , Ti-F 2p 3/2 , Ti-O 2p 3/2 , Ti-C 2p 1/2 , Ti-O 2p 1/2 , and Ti-F 2p 1/2 [ 19 – 22 ]. In addition, O 1s and V 2p are linking together. Figure 5 D shows five peaks at 513.7, 516.2, 520.8,522.5, and 524.3 eV for V 2p originated from V-C 2p 3/2 , V 4+ 2p 3/2 , V-C 2p 1/2 , V 4+ 2p 1/2 and V 5+ 2p 1/2 [ 23 , 24 ], respectively, implying the occurrence of oxidation during the MXene synthesis. In the part of O 1s, there are four peaks at 529.8, 530.4, 531.8,and 532.9 eV, which can be assigned to the Ti-O-Ti, V-O, C-O, and O-H, respectively [ 19 ]. 3.2 Electrochemical investigation 3.2.1 Modification process Cyclic voltammetry (CV) and electrochemical impedance spectroscopy techniques (EIS) were used to investigate the modification process of the SPCE in a solution containing [Fe(CN) 6 ] 3−/4− as a standard probe. The cyclic voltammogram of a SPCE (Fig. 6 A, curve a) was improved by modifying with TiVC-MXene (curve b) and TiVC-MXene/Au NPs (curve e), respectively. These improvements confirm good electrical conductivity of TiVC-MXene and Au NPs as catalysts and complete layer-by-layer modification of the SPCE. In next step and after modifying TiVC-MXene/Au NPs with Pb 2+ -aptamer, the oxidation current of standard probe was decreased that showed addition of a nonconductive layer on the electrode surface (curve d). In the final step, the oxidation signal of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer was reduced after addition of HER2 due to low conductivity of protein (curve c). The same results were observed in EIS signals, and the maximum R ct was observed for the SPCE (Fig. 6 B curve a) compared to the lower R ct observed following modification of the SPCE with TiVC-MXene and Au NPs (Curves b and c), respectively. These observations suggest that the SPCE modification with TiVC-MXene and Au NPs led to a decrease in charge transfer resistance. On the other hand, value of R ct was reduced after modification of SPCE/TiVC-MXene/Au NPs with Pb 2+ -aptamer and HER2, which are in agreement with the CV results. 3.2.2 Optimization of effective factors To achieve the highest level of accuracy in the determination performance, we optimized the experimental conditions, including the concentration of Pb 2+ and incubation time of the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer in HER2 solution (Fig. 7 A and B). Obviously, with increment of the Pb 2+ concentration from 0.5 to 5 mM, the signal of the square-wave anodic stripping voltammetry (SWASV) was increased due to rising of Pb 2+ adsorbed to the aptamer utilized for the aptasensor fabrication. With moving from 5 mM to 6 mM of Pb 2+ , the analytical signal remained constant due to saturation of the aptamer with Pb 2+ at surface of biosensor (Fig. 7 A). Incubation time for the interaction between HER2 and the aptamer was optimized at the surface of biosensor (Fig. 7 B). By increasing the incubation time up to 60 minutes, the SWASV signal of Pb 2+ decreased due to the replacement of Pb 2+ with HER2 in the aptamer structure and the removal of of Pb 2+ from the surface of the aptasensor. After 60 minutes, the analytical signal of Pb 2+ remained constant due to the completion of the interaction process. The type of buffer on biosensor activity was checked in the presence of PBS, Tris-HCl, and Britton-Robinson buffer as potential options to maintain neutral conditions. The results, shown in Fig. 7 C, indicate that the optimal biosensor activity was observed in the Tris-HCl buffer solution. Therefore, this buffer was selected for use in subsequent steps. 3.2.3 Interaction effect and analytical parameters Interaction of HER2 as a breast biomarker with SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamerto monitor breast cancer was checked in this step. In this regard, SWASVs of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer were recorded in the absence and the presence of 290 and 380 pg/mL of HER2 that showed in Fig. 8 . The decrement of the peak current of SWASV after addition of HER2 (curve a) can be the result of the specific interaction of HER2 with aptamer on the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamerand release of Pb + 2 ions into the solution. 3.3 Analytical performance of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer After optimizing the effective parameters and identifying the best conditions for biosensor application, the performance of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer in monitoring HER2 was evaluated. The results are presented in Fig. 9 , showcasing a dynamic range of 0.0‒1200 pg/mL with the equation ΔΙ = 0.1417C + 6.1161 (R 2 = 0.9947) and a limit of detection (LOD) of 2.11 fg/mL (3S/m), which is deemed acceptable when compared to previously reported studies (Table 1 ). Table 1 Evaluating the performance of the fabricated biosensors for HER2 analysis Electrode Modifier LDR LOD Ref. SPCE Au/NPs + MWCNTs + antibody-antigen 7.5‒50 ng/mL 0.16 ng/mL [ 25 ] GCE Au NPs + polyethylene glycol + peptide + poly(3,4-ethylene-dioxythiophene) 1.0 pg/mL ‒1 µg/mL 0.44 pg/mL [ 26 ] SPCE Poly-L-lysine + aptamer + methylene blue 10‒60 ng/mL 3.0 ng/mL [ 27 ] Graphite sheet Nitrogen-enhanced carbon quantum dots + bovine serum albumin + antibody 0.1‒1.0 ng/mL 4.8 pg/mL [ 28 ] Au electrode Au nanorod@Pd + aptamer + horseradish peroxidase 0–200 ng/mL 0.15 ng/mL [ 29 ] SPCE TiVC-MXene/Au NPs/Pb 2+ -aptamer 0–1200 pg/mL 2.11 fg/mL Present work 3.4 Stability, selectivity, and real sample analysis The stability of the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer for monitoring 380 pg/mL of HER2 was checked for a period of 25 days. Based on the information presented in Fig. 10 A, the biosensor exhibited effective stability for monitoring HER2 over a span of three weeks, but thereafter experienced a decrease in performance for HER2 monitoring. Furthermore, the selectivity of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer in detecting HER2 alongside various breast biomarkers such as CEA, ER, and PR was explored. Figure 10 B illustrates the results confirming acceptable selectivity of the developed aptasensor towards HER2. The performance of SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer in HER2monitoring in normal serum was checked (Table 2 ). As can be seen, the recovery range clearly confirm powerful ability of TiVC-Maxene/Au-NP/AP-Pb 2+ /SPCE for monitoring of HER2. Table 2 Exploring the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer ability for monitoring of HER2 in real sample. Sample Added HER2/ pg/mL Founded HER2/ pg/mL Recovery% Normal serum 1 --- < LOD --- 20.0 19.85 ± 0.28 99.25 Normal serum 2 --- < LOD --- 100 103.6 ± 4.2 103.6 4 Conclusion Here, a new biosensor (SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer) was designed, fabricated by layer-by-layer modification strategy, and used for detecting HER2 breast cancer biosensor. The Pb 2+ signal was used as an analytical approach for the detection of HER2 biomarker in the concentration range of 0‒1200 pg/mL with a LOD of 2.11 fg/mL. In addition, the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer illustrated excellent selectivity for HER2 in the presence of other types of breast biomarkers such as CEA, ER, and PR. In the final step, the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer successfully was applied for monitoring HER2 in real sample with acceptable recovery range. Declarations Competing interests : The authors state that they have no conflicts of interest. Funding: No funding has been provided for this research project. The paper is a component of Miss. Najmeh Zare's PhD thesis, and the authors express their gratitude to the School of Resources and Environment at the University of Electronic Science and Technology of China. Author Contribution Najmeh Zare and Dr. Zhouxiang Zhang: Characterization of data and analysis of experimental part. Prof. Hassan Karimi-Maleh: supervisor of workYangpin Wen, Nianbing Zhongc and Li Fu: Writing- Original draft preparation and revise of paper. References Aronson JK, Ferner RE (2017) Biomarkers—a general review. Curr protocols Pharmacol 76(1):9 1-9.23. 17 Dave S, Dave A, Radhakrishnan S, Das J, Dave S (2022) Biosensors for healthcare: an artificial intelligence approach, Biosensors for Emerging and Re-Emerging Infectious Diseases 365–383 Krishnamurti U, Silverman JF (2014) HER2 in breast cancer: a review and update. Adv Anat Pathol 21(2):100–107 Perez EA, Cortés J, Gonzalez-Angulo AM, Bartlett JM (2014) HER2 testing: current status and future directions. Cancer Treat Rev 40(2):276–284 Ahirwar R (2021) Recent advances in nanomaterials-based electrochemical immunosensors and aptasensors for HER2 assessment in breast cancer. Microchim Acta 188(10):317 Freitas M, Nouws HP, Delerue-Matos C (2018) Electrochemical Biosensing in Cancer Diagnostics and Follow‐up. Electroanalysis 30(8):1584–1603 Anasori B, Xie Y, Beidaghi M, Lu J, Hosler BC, Hultman L, Kent PR, Gogotsi Y, Barsoum MW (2015) Two-dimensional, ordered, double transition metals carbides (MXenes). ACS Nano 9(10):9507–9516 Alhabeb M, Maleski K, Anasori B, Lelyukh P, Clark L, Sin S, Gogotsi Y (2017) Guidelines for synthesis and processing of two-dimensional titanium carbide (Ti3C2T x MXene). Chem Mater 29(18):7633–7644 Lipatov A, Alhabeb M, Lukatskaya MR, Boson A, Gogotsi Y, Sinitskii A (2016) Effect of synthesis on quality, electronic properties and environmental stability of individual monolayer Ti3C2 MXene flakes. Adv Electron Mater 2(12):1600255 Shahzad F, Alhabeb M, Hatter CB, Anasori B, Man Hong S, Koo CM, Gogotsi Y (2016) Electromagnetic interference shielding with 2D transition metal carbides (MXenes). Science 353(6304):1137–1140 Wu L, Lu X, Wu Z-S, Dong Y, Wang X, Zheng S, Chen J (2018) 2D transition metal carbide MXene as a robust biosensing platform for enzyme immobilization and ultrasensitive detection of phenol. Biosens Bioelectron 107:69–75 Sivasankarapillai VS, Sharma TSK, Hwa K-Y, Wabaidur SM, Angaiah S, Dhanusuraman R (2022) MXene based sensing materials: current status and future perspectives. ES Energy Environ 15:4–14 Zhang Q, Wang F, Zhang H, Zhang Y, Liu M, Liu Y (2018) Universal Ti3C2 MXenes based self-standard ratiometric fluorescence resonance energy transfer platform for highly sensitive detection of exosomes. Anal Chem 90(21):12737–12744 Mohammadniaei M, Koyappayil A, Sun Y, Min J, Lee M-H (2020) Gold nanoparticle/MXene for multiple and sensitive detection of oncomiRs based on synergetic signal amplification. Biosens Bioelectron 159:112208 Wang H, Li H, Huang Y, Xiong M, Wang F, Li C (2019) A label-free electrochemical biosensor for highly sensitive detection of gliotoxin based on DNA nanostructure/MXene nanocomplexes. Biosens Bioelectron 142:111531 Hojjati-Najafabadi A, Salmanpour S, Sen F, Asrami PN, Mahdavian M, Khalilzadeh MA (2021) A tramadol drug electrochemical sensor amplified by biosynthesized Au nanoparticle using mentha aquatic extract and ionic liquid. Top Catal 1–8 You Q, Zhuang L, Chang Z, Ge M, Mei Q, Yang L, Dong W-F (2022) Hierarchical Au nanoarrays functionalized 2D Ti2CTx MXene membranes for the detection of exosomes isolated from human lung carcinoma cells. Biosens Bioelectron 216:114647 Yazdanparast S, Soltanmohammad S, Fash-White A, Tucker GJ, Brennecka GL (2020) Synthesis and surface chemistry of 2D TiVC solid-solution MXenes. ACS Appl Mater Interfaces 12(17):20129–20137 Feng K, Li Y, Xu C, Zhang M, Yang X, Cheng Y, Wang Y, Yang L, Yin S (2023) In-situ partial oxidation of TiVCTx derived TiO2 and V2O5 nanocrystals functionalized TiVCTx MXene as anode for lithium-ion batteries. Electrochim Acta 444:142022 Tao M, Zhang Y, Zhan R, Guo B, Xu Q, Xu M (2018) A chemically bonded CoNiO2 nanoparticles/MXene composite as anode for sodium-ion batteries. Mater Lett 230:173–176 Li Y, Zhang J, Cheng Y, Feng K, Li J, Yang L, Yin S (2022) Stable TiVCTx/poly-o-phenylenediamine composites with three-dimensional tremella-like architecture for supercapacitor and Li-ion battery applications. Chem Eng J 433:134578 Tian Y, An Y, Wei H, Wei C, Tao Y, Li Y, Xi B, Xiong S, Feng J, Qian Y (2020) Micron-sized nanoporous vanadium pentoxide arrays for high-performance gel zinc-ion batteries and potassium batteries. Chem Mater 32(9):4054–4064 Zhou J, Lin S, Huang Y, Tong P, Zhao B, Zhu X, Sun Y (2019) Synthesis and lithium ion storage performance of two-dimensional V4C3 MXene. Chem Eng J 373:203–212 Wang X, Lin S, Tong H, Huang Y, Tong P, Zhao B, Dai J, Liang C, Wang H, Zhu X (2019) Two-dimensional V4C3 MXene as high performance electrode materials for supercapacitors. Electrochim Acta 307:414–421 Freitas M, Nouws HP, Delerue-Matos C (2019) Electrochemical sensing platforms for HER2‐ECD breast cancer biomarker detection. Electroanalysis 31(1):121–128 Yang X, Chen P, Zhang X, Zhou H, Song Z, Yang W, Luo X (2023) An electrochemical biosensor for HER2 detection in complex biological media based on two antifouling materials of designed recognizing peptide and PEG. Anal Chim Acta 1252:341075 Bezerra G, Córdula C, Campos D, Nascimento G, Oliveira N, Seabra MA, Visani V, Lucas S, Lopes I, Santos J (2019) Electrochemical aptasensor for the detection of HER2 in human serum to assist in the diagnosis of early stage breast cancer. Anal Bioanal Chem 411:6667–6676 Amir H, Subramanian V, Sornambikai S, Ponpandian N, Viswanathan C (2024) Nitrogen-enhanced carbon quantum dots mediated immunosensor for electrochemical detection of HER2 breast cancer biomarker. Bioelectrochemistry 155:108589 Chen D, Wang D, Hu X, Long G, Zhang Y, Zhou L (2019) A DNA nanostructured biosensor for electrochemical analysis of HER2 using bioconjugate of GNR@ Pd SSs—Apt—HRP. Sens Actuators B 296:126650 Scheme 1 Scheme 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files scheme1.png Scheme 1 A diagrammatic representation depicting the steps involved in creating the SPCE/TiVC-MXene/Au NPs/Pb 2+ -aptamer structure used in the detection of HER2. Cite Share Download PDF Status: Published Journal Publication published 02 Oct, 2024 Read the published version in Advanced Composites and Hybrid Materials → Version 1 posted Editorial decision: Revision requested 04 Jun, 2024 Reviews received at journal 31 May, 2024 Reviews received at journal 31 May, 2024 Reviewers agreed at journal 30 May, 2024 Reviews received at journal 30 May, 2024 Reviewers agreed at journal 28 May, 2024 Reviewers agreed at journal 28 May, 2024 Reviewers invited by journal 28 May, 2024 Editor assigned by journal 28 May, 2024 Submission checks completed at journal 28 May, 2024 First submitted to journal 10 May, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4399330","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":310615316,"identity":"6bb0c710-12ef-4b1a-aee3-36bb2b8ebcfe","order_by":0,"name":"Najmeh Zare","email":"","orcid":"","institution":"University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Najmeh","middleName":"","lastName":"Zare","suffix":""},{"id":310615317,"identity":"87bed928-adc5-4826-93f7-ee2c346bf288","order_by":1,"name":"Hassan Karimi-Maleh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAy0lEQVRIiWNgGAWjYBACgwNgygbGZyZaSxpMNfFaDpOi5fjxxx9+7jif2M9//uAHhgrrxAb2swfwarE/k2Mm2XvmduLMGcnMEgxn0hMbePISCDgsh42Bt+124oYbzGwMjG2HExskeAzwazn//PHHv23nEvefPwzU8o8YLTcSDKR52w4kbmBIBmppIErLGzNp2bZk4xk3ko0lEo6lG7fx5BByWPrjj2/b7GT7+w8+/PChxlq2n/0Mfi2oIAGI2UhQPwpGwSgYBaMABwAAo0NI55IRlHsAAAAASUVORK5CYII=","orcid":"","institution":"University of Electronic Science and Technology of China","correspondingAuthor":true,"prefix":"","firstName":"Hassan","middleName":"","lastName":"Karimi-Maleh","suffix":""},{"id":310615318,"identity":"a47a4d39-a2d9-4bdd-a113-d77d31102b90","order_by":2,"name":"Zhouxiang Zhang","email":"","orcid":"","institution":"University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Zhouxiang","middleName":"","lastName":"Zhang","suffix":""},{"id":310615319,"identity":"727cc3bb-a642-4be6-91cc-2475ae714c9e","order_by":3,"name":"Yangpin Wen","email":"","orcid":"","institution":"Jiangxi Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Yangpin","middleName":"","lastName":"Wen","suffix":""},{"id":310615320,"identity":"efafb90b-b652-478e-81a1-7cbab9f16275","order_by":4,"name":"Nianbing Zhong","email":"","orcid":"","institution":"Chongqing University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Nianbing","middleName":"","lastName":"Zhong","suffix":""},{"id":310615321,"identity":"a4dda4ef-fd87-4b10-92d9-cb83853b8a30","order_by":5,"name":"Li Fu","email":"","orcid":"","institution":"Hangzhou Dianzi University","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Fu","suffix":""}],"badges":[],"createdAt":"2024-05-10 08:33:49","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4399330/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4399330/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s42114-024-00966-8","type":"published","date":"2024-10-02T15:57:20+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":58037837,"identity":"a83f897e-695f-4e5b-9329-d4d102d28130","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":577105,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images and MAP analyses of (A) TiVAlC Max phase and (B) TiVC-MXene\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/5ae93d23bc2a6d428c7549cb.png"},{"id":58037840,"identity":"bc5b0886-039e-47fc-9592-7832e4411f2b","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":6277054,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images and EDS spectra of (A and C) TiVAlC Max phase and (B and D) TiVC-MXene .\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/163a9e336e1931491d43dc54.png"},{"id":58038475,"identity":"2a63a524-abbd-4463-97f6-7773b4a998cc","added_by":"auto","created_at":"2024-06-10 09:44:46","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":586267,"visible":true,"origin":"","legend":"\u003cp\u003e(A) AFM image of TiVC-MXene and (B) isotherms of nitrogen absorption–desorption (BET), and inset of (B) BJH pore size distribution of the TiVC-MXene.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/625d054a4ad8332f4d418a0d.png"},{"id":58037841,"identity":"1c193d2d-49db-466d-8770-5a09227b0d4c","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":174870,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of TiVC-MXene (a) and TiVAlC Max phase (b)\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/8daa8c64427802d9e10c98ba.png"},{"id":58037839,"identity":"fb9ce2c6-10eb-499e-bce2-7f04d1e13878","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1036241,"visible":true,"origin":"","legend":"\u003cp\u003eXPS wide range spectra of TiVAlC and TiVC-MXene (A) and C 1s (B), Ti 2\u003csub\u003ep\u003c/sub\u003e (C), and O 1\u003csub\u003es\u003c/sub\u003e \u0026amp; 2\u003csub\u003ep\u003c/sub\u003e (D) peaks.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/b360fd3b83866a6f0dda2ac2.png"},{"id":58038476,"identity":"b3473b5c-7053-4b16-b2f9-6b510d769588","added_by":"auto","created_at":"2024-06-10 09:44:46","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":309331,"visible":true,"origin":"","legend":"\u003cp\u003eEIS (A) and CVs (B) of the bare SPCE (a), SPCE/TiVC-MXene (b), SPCE/TiVC-MXene/Au NPs (e), SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer (d), and SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer/HER2 (c) recorded in a solution containing 1.0 mM Fe(CN)\u003csub\u003e6\u003c/sub\u003e]\u003csup\u003e3-/4-\u003c/sup\u003e as standard probe.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/9ceade17b027292dd71c2ccd.png"},{"id":58037843,"identity":"05e7a2a9-4bf9-4a19-aa5e-5ee04bcb7536","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":812280,"visible":true,"origin":"","legend":"\u003cp\u003eOptimization conditions: concentration of Pb\u003csup\u003e2+\u003c/sup\u003e (A); incubation time of the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer in HER2 solution (B), plot of sensing response \u003cem\u003evs.\u003c/em\u003e type of buffer (C)\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/89539180b295c8b6d5dc8f5e.png"},{"id":58037845,"identity":"0487e463-6a69-486a-a38b-7a4adc4a5b36","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":296437,"visible":true,"origin":"","legend":"\u003cp\u003eSWASVs of the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer recorded in the absence (a) and the presence of 290 pg/mL (b) and 380 pg/mL (c) of HER2.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/48e571176502ec92b7cc1b90.png"},{"id":58037847,"identity":"3883689d-4cf0-4537-a6bc-376e7b79010f","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":354303,"visible":true,"origin":"","legend":"\u003cp\u003eThe plot of repose of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer towards various HER2 concentrations. Inset: SWASVs of HER2 solutions (0.0‒1200 pg/mL) at SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer in a 10 mM Tris-HCl buffer solution (pH 7.4).\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/835b9981b83723927928fc50.png"},{"id":58037844,"identity":"e70530cd-5774-4ed5-ad14-388c8a2e4890","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":284860,"visible":true,"origin":"","legend":"\u003cp\u003e(A) The stability test of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer for detecting of HER2. (B) Selectivity test for developed HER2 aptasensor.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/1350fe0a9fe8a11911bea385.png"},{"id":66097069,"identity":"37a263b0-79a0-4656-b7fb-bd015ef4cb2f","added_by":"auto","created_at":"2024-10-07 16:13:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":13521248,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/7f1b7a36-f57a-4e1d-8c2f-6a42cd35eef1.pdf"},{"id":58037838,"identity":"e9b8d5bf-1335-4691-9666-cb1e6f52e082","added_by":"auto","created_at":"2024-06-10 09:36:46","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":742727,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme 1\u003c/strong\u003e A diagrammatic representation depicting the steps involved in creating the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer structure used in the detection of HER2.\u003c/p\u003e","description":"","filename":"scheme1.png","url":"https://assets-eu.researchsquare.com/files/rs-4399330/v1/43a273151ee31e7aa803bc50.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Enhanced detection of HER2 through a layer-by-layer strategy using a TiVC MXenes/Au nanocomposite amplified analytical biosensor for precise cancer biomarker monitoring","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eBiomarkers application accounts as a powerful and dynamic approach to gain insight into various malignancies. They have a wide range of applications in fields such as analytical epidemiology, randomized clinical trials, screening, diagnosis, and prediction. These biomarkers are used to track changes in tissue constituents or body fluids and provide valuable tools for classifying diseases and risk factors in a consistent manner. In addition, they provide valuable information about the underlying pathogenesis of diseases and expand our knowledge base in this field. Biomarkers are detectable signals detected in biological samples such as blood, urine, or tissue and have a wide range of applications, including disease screening, diagnosis, characterization, and monitoring [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In addition, biological markers play a key role in the development of personalized therapeutic interventions, tailoring treatments to individual patients. They are also valuable in predicting and managing adverse reactions to drugs. Furthermore, biomarkers are utilized in identifying different cell types and conducting pharmacodynamics and dose-response studies. Biomarkers consist of proteins, nucleic acids, hormones, enzymes, and other molecules that are linked to particular biological functions or disease states. Their significance lies in their ability to aid in disease diagnosis, prognosis, treatment monitoring, and prediction of patient outcomes. By measuring and analyzing these biomarkers, healthcare professionals can gain a deeper understanding of the presence, progression and severity of diseases, enabling them to make informed decisions about personalized treatments. The discovery and validation of biomarkers have created a paradigm shift in medicine that facilitates early disease detection, accurate diagnosis, and targeted treatment approaches, ultimately leading to improved patient outcomes and improved healthcare management in general [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Bio-monitoring of cancer biomarkers plays a crucial role in early cancer detection and personalized medicine. Breast cancer can be considered one of the most important cancers, and its measurement can provide valuable assistance in preventing mortality. For this purpose, by measuring the protein level, it is possible to identify one of these proteins, namely HER2, in this context. The HER2 receptor, known as human epidermal growth factor receptor 2, is a type of membrane tyrosine kinase that influences cell proliferation and survival when it is activated. Located on chromosome 17q12, the HER2 oncogene is responsible for the amplification of the HER2 receptor, leading to its overexpression. This amplification is a key driver in the development and progression of certain types of breast cancer. It is estimated that around 15 to 20 percent of breast cancers exhibit HER2 amplification [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The status of HER2 is commonly evaluated using two main methods: immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). IHC measures the expression level of the HER2 protein on the cell membranes, while FISH determines the amplification of the HER2 gene [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Immunohistochemistry (IHC) is a widely used staining technique that enables the quantitative and qualitative measurement of protein antigens in biological and tissue samples. It involves the binding of specific antibodies to the target antigens, facilitating their detection. Immunohistochemical staining is extensively utilized in histopathology departments for various purposes. In contemporary medical practice, the evaluation of tissue-specific genes using immunohistochemistry plays a crucial role in tumor classification at different stages, thereby aiding in the diagnosis process. In addition, the ISH test, a molecular technique, is utilized to identify the overgrowth of the HER2 gene in cancer cells. This method employs probes labeled with fluorescent markers that selectively bind to the HER2 gene region. The number of HER2 gene copies is detected and the ratio of HER2 gene copies to control gene copies is calculated, which allows determination of HER2 amplification. Various methods have been developed to measure the HER2 protein, and biosensors have emerged as a particularly advantageous approach in this context. Biosensors offer several benefits over traditional laboratory detection methods, including enhanced sensitivity and rapid response, compact size and affordability, and the ability to work with small sample volumes. In addition, continuous advances in bioassays increase the accuracy of detecting normal and elevated levels of tumor biomarkers in patients' biological fluids, such as serum, plasma, whole blood, and urine. While various biomarkers including DNA, RNA, proteins, and cells have been identified, protein detection and detection of circulating tumor cells (CTCs) are the most commonly reported methods. These approaches have been validated as tumor biomarkers by widely recognized expert organizations [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Studies have demonstrated that the utilization of a biosensor employing a layer-by-layer strategy for the effective monitoring of HER2 enhances the accuracy of the assay by increasing the available surface area for binding with the analyte, thereby improving sensitivity. In this platform, the sensor is constructed by sequentially depositing TiVC MXenes and Au NPs on the transducer surface. The TiVC MXenes serve as a conductive matrix for signal amplification, while the gold nanoparticles act as scaffolds for the presentation of HER2-specific antibodies.\u003c/p\u003e \u003cp\u003eMXene, a novel class of two-dimensional (2D) metals, has garnered significant attention due to its unique properties. MXenes are derived from the intermediate separation of MAX phases, which are compounds composed of a primary transition metal (such as Ti, V, Sc, Mo, Nb, Cr) from the periodic table, along with aluminum (A) and carbon or nitrogen (X) elements [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. These materials exhibit exceptional characteristics, including a large specific surface area, high metal conductivity, hydrophilicity, and low diffusion barriers. TiVC-MXene has a broad range of applications in various fields, including energy [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], capacitors [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], electromagnetic interference (EMI) shielding [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], and biosensors [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. It exhibits versatile properties that make it suitable for these applications. Furthermore, its surface functional groups (-O, -OH, and -F) make MXene nanosheets highly suitable for aptamer immobilization, facilitating the development of aptasensors that have shown promising contributions in recent years [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGold (Au) nano/microstructures possess multiple functionalities that make them suitable for specific bonding with biological elements [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This characteristic results in an increased number of active sites and enhanced catalytic efficiency, leads to significant improvements in the performance of electrochemical sensors. In this study, we developed a label-free electrochemical aptasensor by decorating TiVC-MXene nanosheets with Au nanoparticles (Au NPs) to immobilize the thiolated HER2 aptamer impregnated withPb\u003csup\u003e2+\u003c/sup\u003e ions on the electrode surface. The synthesized TiVC-MXene/Au NPs nanocomposite exhibited a higher number of active sites for the immobilization of the aptamer, improved electrode conductivity, and accelerated the charge transfer. Subsequently, the aptamer specific to HER2 was attached to the surface of the SPCE/TiVC-MXene/Au NPs through covalent bonding between Au NPs and thiolated aptamer. A novel strategy was employed, utilizing the square wave anodic stripping voltammetry (SWASV) response of Pb\u003csup\u003e2+\u003c/sup\u003e ions captured by aptamer as the indicator signal. This allowed for the direct detection of signal changes when Pb\u003csup\u003e2+\u003c/sup\u003e ions leave the electrode surface due to the interaction of HER2 with the aptamer. To the best of our knowledge, this is one of the most efficient electrochemical aptasensors designed to monitor HER2 in real samples applicable for breast cancer diagnosis.\u003c/p\u003e"},{"header":"2 Experiment section","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials and reagents\u003c/h2\u003e \u003cp\u003eWe acquired Titanium Vanadium Aluminum Carbide (TiVAlC) from Laizhou Kai Kai Ceramic Materials Company, Ltd. located in Shandong, China. The HAuCl\u003csub\u003e4\u003c/sub\u003e\u0026middot;4H\u003csub\u003e2\u003c/sub\u003eO, 6-Mercaptohexanol (MCH), LiF, Pb(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e, Tris(hydroxymethyl)aminomethane (Tris), and Tris(2-carboxyethyl) phosphine hydrochloride (TCEP) were purchased from Adamas (Shanghai Titan Scientific Company, Ltd., China). The substances utilized in this research were of analytical quality and were employed without undergoing any purification procedures.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 TiVC-MXene synthesis\u003c/h2\u003e \u003cp\u003eTiVC-MXene was synthesized as reported by Yazdanparast et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. A solution of 1.9 M LiF in concentrated HCl (approximately 37%) was prepared by adding 1.2 g LiF to 24 mL of HCl solution under ambient condition. Then, 1.0 g of the initial MAX phase was mixed with 12 mL of acidic LiF solution at a temperature of 55 \u003csup\u003eo\u003c/sup\u003eC for a duration of 60 hr, which removed the Al from the MAX phase via etching process. After etching, the resulting mixture was washed with distilled water and separated into powder and supernatant through centrifugation. The powder was subjected to several washing steps until the pH reached approximately 6.0. Finally, the obtained TiVC-MXene was dried at room temperature. Additionally, another portion of TiVAlC-MAX phase was treated with 50% HF for 24 hr at room temperature to compare its elemental composition with the MXene prepared using the LiF/HCl solution.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Preparation of the Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer solution and the TiVC-MXene suspension\u003c/h2\u003e \u003cp\u003eThe aptamer specific to HER2 was acquired from Sangon (Shanghai, China) and used for fabrication of the aptasensor with following sequence:\u003c/p\u003e \u003c/div\u003e\n\u003cp\u003e5'-GGGCCGTCGAACACGAGCATGGGCGGGCCTAGGATGACCTGAGTACTGTCC-3'.\u003c/p\u003e\n\u003cp\u003eStock solutions of the Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer (100 \u0026micro;M) were prepared using Tris\u0026ndash;HCl buffer. The Tris\u0026ndash;HCl buffer consisted of a 1.0 M KCl solution containing 10 mM Tris, 1.0 mM of TCEP and EDTA, which its pH was adjusted to 8.0 using HCl. The prepared stock solutions were stored in the refrigerator. The mixture containing the TiVC-MXene was diluted. Then, 4.5 \u0026micro;L of 0.4 mM aptamer specific to HER2 was added to the diluted mixture. Afterward, a solution of 5 mM Pb\u003csup\u003e2+\u003c/sup\u003e with a volume of 150 mL was added to the mixture. The entire solution was placed on a shaker and incubated overnight, allowing the reaction to occur.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Preparation of the TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer\u0026ndash;based biosensor\u003c/h2\u003e \u003cp\u003eVoltammetric measurements were conducted in a 10 mM Tris\u0026ndash;HCl buffer (pH\u0026thinsp;=\u0026thinsp;7.4). Prior to modifying the screen-printed carbon electrode (SPCE), its surface underwent polishing with 0.05 \u0026micro;m alumina slurry being rubbed on the chamois leather until it became smooth and reflective It was then thoroughly cleaned using ultrasonication in double-distilled deionized water, followed by absolute ethanol, and once again in double-distilled deionized water. Afterward, the electrode surface was air-dried. Next, a 5.0 \u0026micro;L suspension of TiVC-MXene (0.5 mg/mL) was drop-cast onto the SPCE surface and dried using an infrared lamp. The modified SPCE was subsequently placed in a solution of 10 mM HAuCl\u003csub\u003e4\u003c/sub\u003e in 0.1 M KCl for electrodeposition at -0.3 V for 50 seconds, and then air-dried. Afterward, a 30 \u0026micro;L solution of the Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer was dropped onto the modified electrode surface and incubated at 4\u0026deg;C for 12 hours. The SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer was then washed with Tris-HCl buffer (10 mM, pH 7.4). To further enhance the sensing performance, 1 mM MCH was applied onto the modified electrode surface for 1 hr at room temperature, followed by rinsing with Tris-HCl buffer (10 mM, pH 7.4). Later, the aptasensor was incubated in a HER2 solution followed by electrochemical measurements were conducted using square wave anodic striping voltammetry (SWASV) in a 10 mM Tris-HCl buffer solution (pH 7.4). The measurements involved a negative potential sweep from 0.2 to -0.8 V. Each measurement was repeated at least three times.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Procedure of work\u003c/h2\u003e \u003cp\u003eScheme \u003cspan refid=\"Sch1\" class=\"InternalRef\"\u003e1\u003c/span\u003e illustrates a detailed overview of the step-by-step fabrication method of the aptasensor, which has been developed specifically for the purpose of detecting HER2. In this particular research, an electrochemical aptamer-based sensor was developed for the detection of the HER2 biomarker. The sensor utilized a SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer as its framework. The process involved in biocoding synthesis is as follows: HER2 is fully adsorbed onto the surface of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer due to its interaction with the aptamer. Furthermore, the high surface area of TiVC Maxene can effectively improve conductivity of biosensor and loading of aptamer for biomarker detection. The presence of Au NPs guarantees the high electrical conductivity of the aptasensor and the effective binding of the aptamer to the SPCE/TiVC-MXene surface along with expanding the active surface of the biosensor. In the presence of HER2, aptamers on the capture probe selectively recognize HER2 and bind to it. Therefore, the interaction of Pb\u003csup\u003e2+\u003c/sup\u003e ions with aptamer is weakened. As the result, the Pb\u003csup\u003e2+\u003c/sup\u003e ions are released to the solution and the surface concentration of Pb\u003csup\u003e2+\u003c/sup\u003e ions decreases.\u003c/p\u003e \u003cp\u003eConcurrently, the peak current of Pb\u003csup\u003e2+\u003c/sup\u003e in the recorded SWASVs decreases Scheme \u003cspan refid=\"Sch1\" class=\"InternalRef\"\u003e1\u003c/span\u003e provides a visual representation of this process.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3 Results and discussions","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Characterization of TiVC-MXene\u003c/h2\u003e \u003cp\u003eAccording to Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA, the TiVAlC Max phase has a complex and dense layered structure. On the other hand, mapping analysis of TiVAlC Max phase shows the presence of Ti, V, Al, and C elements with good distribution that confirms the high purity of precursor used for TiVC-MXene fabrication. Once the precursor is washed with a LiF/HCl solution and the aluminum layer is removed, the distinct structure of separate layers with visible empty spaces between them becomes apparent (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). This observation serves as a confirmation of the accurate and suitable synthesis of TiVC-MXene.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe mapping analysis reveals that the removal of the aluminum layer has been carried out to the best extent possible, and structure of TiVC-MXene formed with some empty layers as expected.\u003c/p\u003e \u003cp\u003eCompared to the thin-layer TEM image of TiVC-MXene (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB), the TEM image of Max phase (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA) exhibits a denser and compact microstructure. The elements analysis images of Max phase and MXene (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD) shows that the aluminum has been successfully removed to the maximum extent possible, leading to the well-established synthesis of MXene with the desired structure.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe atomic force microscopy (AFM) image in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA depicts the layered structure of TiVC-MXene, showing distinct layers that confirm the removal of the aluminum layer and the synthesis of TiVC-MXene with the expected thin layer size. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB illustrates the 2D configuration of TiVC-MXene, revealing a H4 loop under a type IV isotherm, suggesting the existence of a mesoporous framework. The specific surface area of TiVC-MXene was calculated to be 2.11 m\u003csup\u003e2\u003c/sup\u003e/g. The PSD histogram of TiVC-MXene exhibits an average pore diameter of 33 nm.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe X-ray diffraction (XRD) patterns in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e reveals the structure characteristics of TiVC-MXene and TiVAlC Max phase. The dominant crystal planes observed in the XRD patterns are (002) and (103), the Max phase peaks showed a substantial reduction in intensity and shift towards positive values after being subjected to etching. These findings strongly indicate the successful completion of the synthesis process that match with reported XRD patterns of TiVC-MXene and utilized Max phase [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe valence bond states and elemental composition of the synthesized TiVAlC and TiVC-MXene were examined by XPS. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eA displays the XPS full survey spectra of TiAlVC and TiVC\u003csub\u003e\u0026minus;\u003c/sub\u003eMXene, demonstrating the coexistence of Ti, O, C, F, V and Al elements. Figures\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eB-D exhibit the high-resolution XPS results of C 1s, Ti 2p and O 1s \u0026amp; V 2p, respectively. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eB shows four peaks for C 1s at 285.1, 284.7, 286.1,and 288.7 eV, which can be assigned to the C-Ti(V), C-C, C\u0026thinsp;=\u0026thinsp;O, and O-C\u0026thinsp;=\u0026thinsp;O [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eC depicts six peaks at 455.3, 456.4, 458.7, 461.4, 463.4,and 464.7 eV for Ti 2p, matching with Ti-C 2p\u003csub\u003e3/2\u003c/sub\u003e, Ti-F 2p\u003csub\u003e3/2\u003c/sub\u003e, Ti-O 2p\u003csub\u003e3/2\u003c/sub\u003e, Ti-C 2p\u003csub\u003e1/2\u003c/sub\u003e, Ti-O 2p\u003csub\u003e1/2\u003c/sub\u003e, and Ti-F 2p\u003csub\u003e1/2\u003c/sub\u003e [\u003cspan additionalcitationids=\"CR20 CR21\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. In addition, O 1s and V 2p are linking together. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eD shows five peaks at 513.7, 516.2, 520.8,522.5, and 524.3 eV for V 2p originated from V-C 2p\u003csub\u003e3/2\u003c/sub\u003e, V\u003csup\u003e4+\u003c/sup\u003e 2p\u003csub\u003e3/2\u003c/sub\u003e, V-C 2p\u003csub\u003e1/2\u003c/sub\u003e, V\u003csup\u003e4+\u003c/sup\u003e 2p\u003csub\u003e1/2\u003c/sub\u003e and V\u003csup\u003e5+\u003c/sup\u003e 2p\u003csub\u003e1/2\u003c/sub\u003e [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], respectively, implying the occurrence of oxidation during the MXene synthesis. In the part of O 1s, there are four peaks at 529.8, 530.4, 531.8,and 532.9 eV, which can be assigned to the Ti-O-Ti, V-O, C-O, and O-H, respectively [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Electrochemical investigation\u003c/h2\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1 Modification process\u003c/h2\u003e \u003cp\u003eCyclic voltammetry (CV) and electrochemical impedance spectroscopy techniques (EIS) were used to investigate the modification process of the SPCE in a solution containing [Fe(CN)\u003csub\u003e6\u003c/sub\u003e] \u003csup\u003e3\u0026minus;/4\u0026minus;\u003c/sup\u003e as a standard probe. The cyclic voltammogram of a SPCE (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eA, curve a) was improved by modifying with TiVC-MXene (curve b) and TiVC-MXene/Au NPs (curve e), respectively. These improvements confirm good electrical conductivity of TiVC-MXene and Au NPs as catalysts and complete layer-by-layer modification of the SPCE. In next step and after modifying TiVC-MXene/Au NPs with Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer, the oxidation current of standard probe was decreased that showed addition of a nonconductive layer on the electrode surface (curve d). In the final step, the oxidation signal of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer was reduced after addition of HER2 due to low conductivity of protein (curve c). The same results were observed in EIS signals, and the maximum R\u003csub\u003ect\u003c/sub\u003e was observed for the SPCE (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eB curve a) compared to the lower R\u003csub\u003ect\u003c/sub\u003e observed following modification of the SPCE with TiVC-MXene and Au NPs (Curves b and c), respectively. These observations suggest that the SPCE modification with TiVC-MXene and Au NPs led to a decrease in charge transfer resistance. On the other hand, value of R\u003csub\u003ect\u003c/sub\u003e was reduced after modification of SPCE/TiVC-MXene/Au NPs with Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer and HER2, which are in agreement with the CV results.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2 Optimization of effective factors\u003c/h2\u003e \u003cp\u003eTo achieve the highest level of accuracy in the determination performance, we optimized the experimental conditions, including the concentration of Pb\u003csup\u003e2+\u003c/sup\u003e and incubation time of the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer in HER2 solution (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eA and B). Obviously, with increment of the Pb\u003csup\u003e2+\u003c/sup\u003e concentration from 0.5 to 5 mM, the signal of the square-wave anodic stripping voltammetry (SWASV) was increased due to rising of Pb\u003csup\u003e2+\u003c/sup\u003e adsorbed to the aptamer utilized for the aptasensor fabrication. With moving from 5 mM to 6 mM of Pb\u003csup\u003e2+\u003c/sup\u003e, the analytical signal remained constant due to saturation of the aptamer with Pb\u003csup\u003e2+\u003c/sup\u003e at surface of biosensor (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eA). Incubation time for the interaction between HER2 and the aptamer was optimized at the surface of biosensor (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eB). By increasing the incubation time up to 60 minutes, the SWASV signal of Pb\u003csup\u003e2+\u003c/sup\u003e decreased due to the replacement of Pb\u003csup\u003e2+\u003c/sup\u003e with HER2 in the aptamer structure and the removal of of Pb\u003csup\u003e2+\u003c/sup\u003e from the surface of the aptasensor. After 60 minutes, the analytical signal of Pb\u003csup\u003e2+\u003c/sup\u003e remained constant due to the completion of the interaction process.\u003c/p\u003e \u003cp\u003eThe type of buffer on biosensor activity was checked in the presence of PBS, Tris-HCl, and Britton-Robinson buffer as potential options to maintain neutral conditions. The results, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eC, indicate that the optimal biosensor activity was observed in the Tris-HCl buffer solution. Therefore, this buffer was selected for use in subsequent steps.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e3.2.3 Interaction effect and analytical parameters\u003c/h2\u003e \u003cp\u003eInteraction of HER2 as a breast biomarker with SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamerto monitor breast cancer was checked in this step. In this regard, SWASVs of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer were recorded in the absence and the presence of 290 and 380 pg/mL of HER2 that showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. The decrement of the peak current of SWASV after addition of HER2 (curve a) can be the result of the specific interaction of HER2 with aptamer on the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamerand release of Pb\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e ions into the solution.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Analytical performance of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer\u003c/h2\u003e \u003cp\u003eAfter optimizing the effective parameters and identifying the best conditions for biosensor application, the performance of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer in monitoring HER2 was evaluated. The results are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, showcasing a dynamic range of 0.0‒1200 pg/mL with the equation ΔΙ\u0026thinsp;=\u0026thinsp;0.1417C\u0026thinsp;+\u0026thinsp;6.1161 (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.9947) and a limit of detection (LOD) of 2.11 fg/mL (3S/m), which is deemed acceptable when compared to previously reported studies (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEvaluating the performance of the fabricated biosensors for HER2 analysis\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectrode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModifier\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLDR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLOD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRef.\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSPCE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAu/NPs\u0026thinsp;+\u0026thinsp;MWCNTs\u0026thinsp;+\u0026thinsp;antibody-antigen\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.5‒50 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.16 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGCE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAu NPs\u0026thinsp;+\u0026thinsp;polyethylene glycol\u0026thinsp;+\u0026thinsp;peptide\u0026thinsp;+\u0026thinsp;poly(3,4-ethylene-dioxythiophene)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.0 pg/mL ‒1 \u0026micro;g/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.44 pg/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSPCE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePoly-L-lysine\u0026thinsp;+\u0026thinsp;aptamer\u0026thinsp;+\u0026thinsp;methylene blue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10‒60 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.0 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGraphite sheet\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNitrogen-enhanced carbon quantum dots\u0026thinsp;+\u0026thinsp;bovine serum albumin\u0026thinsp;+\u0026thinsp;antibody\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.1‒1.0 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.8 pg/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAu electrode\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAu nanorod@Pd\u0026thinsp;+\u0026thinsp;aptamer\u0026thinsp;+\u0026thinsp;horseradish peroxidase\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u0026ndash;200 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.15 ng/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSPCE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u0026ndash;1200 pg/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.11 fg/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePresent work\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Stability, selectivity, and real sample analysis\u003c/h2\u003e \u003cp\u003eThe stability of the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer for monitoring 380 pg/mL of HER2 was checked for a period of 25 days. Based on the information presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003eA, the biosensor exhibited effective stability for monitoring HER2 over a span of three weeks, but thereafter experienced a decrease in performance for HER2 monitoring.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFurthermore, the selectivity of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer in detecting HER2 alongside various breast biomarkers such as CEA, ER, and PR was explored. Figure\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003eB illustrates the results confirming acceptable selectivity of the developed aptasensor towards HER2.\u003c/p\u003e \u003cp\u003eThe performance of SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer in HER2monitoring in normal serum was checked (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). As can be seen, the recovery range clearly confirm powerful ability of TiVC-Maxene/Au-NP/AP-Pb\u003csup\u003e2+\u003c/sup\u003e/SPCE for monitoring of HER2.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eExploring the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer ability for monitoring of HER2 in real sample.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAdded HER2/ pg/mL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFounded HER2/ pg/mL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRecovery%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNormal serum 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e---\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt; LOD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e---\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNormal serum 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e---\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt; LOD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e---\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e103.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e103.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4 Conclusion","content":"\u003cp\u003eHere, a new biosensor (SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer) was designed, fabricated by layer-by-layer modification strategy, and used for detecting HER2 breast cancer biosensor. The Pb\u003csup\u003e2+\u003c/sup\u003e signal was used as an analytical approach for the detection of HER2 biomarker in the concentration range of 0‒1200 pg/mL with a LOD of 2.11 fg/mL. In addition, the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer illustrated excellent selectivity for HER2 in the presence of other types of breast biomarkers such as CEA, ER, and PR. In the final step, the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer successfully was applied for monitoring HER2 in real sample with acceptable recovery range.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003e \u003cb\u003eCompeting interests\u003c/b\u003e:\u003c/h2\u003e \u003cp\u003eThe authors state that they have no conflicts of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eNo funding has been provided for this research project. The paper is a component of Miss. Najmeh Zare's PhD thesis, and the authors express their gratitude to the School of Resources and Environment at the University of Electronic Science and Technology of China.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eNajmeh Zare and Dr. Zhouxiang Zhang: Characterization of data and analysis of experimental part. Prof. Hassan Karimi-Maleh: supervisor of workYangpin Wen, Nianbing Zhongc and Li Fu: Writing- Original draft preparation and revise of paper.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAronson JK, Ferner RE (2017) Biomarkers\u0026mdash;a general review. Curr protocols Pharmacol 76(1):9 1-9.23. 17\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDave S, Dave A, Radhakrishnan S, Das J, Dave S (2022) Biosensors for healthcare: an artificial intelligence approach, Biosensors for Emerging and Re-Emerging Infectious Diseases 365\u0026ndash;383\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrishnamurti U, Silverman JF (2014) HER2 in breast cancer: a review and update. Adv Anat Pathol 21(2):100\u0026ndash;107\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePerez EA, Cort\u0026eacute;s J, Gonzalez-Angulo AM, Bartlett JM (2014) HER2 testing: current status and future directions. Cancer Treat Rev 40(2):276\u0026ndash;284\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhirwar R (2021) Recent advances in nanomaterials-based electrochemical immunosensors and aptasensors for HER2 assessment in breast cancer. Microchim Acta 188(10):317\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFreitas M, Nouws HP, Delerue-Matos C (2018) Electrochemical Biosensing in Cancer Diagnostics and Follow‐up. Electroanalysis 30(8):1584\u0026ndash;1603\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnasori B, Xie Y, Beidaghi M, Lu J, Hosler BC, Hultman L, Kent PR, Gogotsi Y, Barsoum MW (2015) Two-dimensional, ordered, double transition metals carbides (MXenes). ACS Nano 9(10):9507\u0026ndash;9516\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlhabeb M, Maleski K, Anasori B, Lelyukh P, Clark L, Sin S, Gogotsi Y (2017) Guidelines for synthesis and processing of two-dimensional titanium carbide (Ti3C2T x MXene). Chem Mater 29(18):7633\u0026ndash;7644\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLipatov A, Alhabeb M, Lukatskaya MR, Boson A, Gogotsi Y, Sinitskii A (2016) Effect of synthesis on quality, electronic properties and environmental stability of individual monolayer Ti3C2 MXene flakes. Adv Electron Mater 2(12):1600255\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShahzad F, Alhabeb M, Hatter CB, Anasori B, Man Hong S, Koo CM, Gogotsi Y (2016) Electromagnetic interference shielding with 2D transition metal carbides (MXenes). Science 353(6304):1137\u0026ndash;1140\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu L, Lu X, Wu Z-S, Dong Y, Wang X, Zheng S, Chen J (2018) 2D transition metal carbide MXene as a robust biosensing platform for enzyme immobilization and ultrasensitive detection of phenol. Biosens Bioelectron 107:69\u0026ndash;75\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSivasankarapillai VS, Sharma TSK, Hwa K-Y, Wabaidur SM, Angaiah S, Dhanusuraman R (2022) MXene based sensing materials: current status and future perspectives. ES Energy Environ 15:4\u0026ndash;14\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Q, Wang F, Zhang H, Zhang Y, Liu M, Liu Y (2018) Universal Ti3C2 MXenes based self-standard ratiometric fluorescence resonance energy transfer platform for highly sensitive detection of exosomes. Anal Chem 90(21):12737\u0026ndash;12744\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMohammadniaei M, Koyappayil A, Sun Y, Min J, Lee M-H (2020) Gold nanoparticle/MXene for multiple and sensitive detection of oncomiRs based on synergetic signal amplification. Biosens Bioelectron 159:112208\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang H, Li H, Huang Y, Xiong M, Wang F, Li C (2019) A label-free electrochemical biosensor for highly sensitive detection of gliotoxin based on DNA nanostructure/MXene nanocomplexes. Biosens Bioelectron 142:111531\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHojjati-Najafabadi A, Salmanpour S, Sen F, Asrami PN, Mahdavian M, Khalilzadeh MA (2021) A tramadol drug electrochemical sensor amplified by biosynthesized Au nanoparticle using mentha aquatic extract and ionic liquid. Top Catal 1\u0026ndash;8\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYou Q, Zhuang L, Chang Z, Ge M, Mei Q, Yang L, Dong W-F (2022) Hierarchical Au nanoarrays functionalized 2D Ti2CTx MXene membranes for the detection of exosomes isolated from human lung carcinoma cells. Biosens Bioelectron 216:114647\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYazdanparast S, Soltanmohammad S, Fash-White A, Tucker GJ, Brennecka GL (2020) Synthesis and surface chemistry of 2D TiVC solid-solution MXenes. ACS Appl Mater Interfaces 12(17):20129\u0026ndash;20137\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFeng K, Li Y, Xu C, Zhang M, Yang X, Cheng Y, Wang Y, Yang L, Yin S (2023) In-situ partial oxidation of TiVCTx derived TiO2 and V2O5 nanocrystals functionalized TiVCTx MXene as anode for lithium-ion batteries. Electrochim Acta 444:142022\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTao M, Zhang Y, Zhan R, Guo B, Xu Q, Xu M (2018) A chemically bonded CoNiO2 nanoparticles/MXene composite as anode for sodium-ion batteries. Mater Lett 230:173\u0026ndash;176\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi Y, Zhang J, Cheng Y, Feng K, Li J, Yang L, Yin S (2022) Stable TiVCTx/poly-o-phenylenediamine composites with three-dimensional tremella-like architecture for supercapacitor and Li-ion battery applications. Chem Eng J 433:134578\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTian Y, An Y, Wei H, Wei C, Tao Y, Li Y, Xi B, Xiong S, Feng J, Qian Y (2020) Micron-sized nanoporous vanadium pentoxide arrays for high-performance gel zinc-ion batteries and potassium batteries. Chem Mater 32(9):4054\u0026ndash;4064\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhou J, Lin S, Huang Y, Tong P, Zhao B, Zhu X, Sun Y (2019) Synthesis and lithium ion storage performance of two-dimensional V4C3 MXene. Chem Eng J 373:203\u0026ndash;212\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang X, Lin S, Tong H, Huang Y, Tong P, Zhao B, Dai J, Liang C, Wang H, Zhu X (2019) Two-dimensional V4C3 MXene as high performance electrode materials for supercapacitors. Electrochim Acta 307:414\u0026ndash;421\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFreitas M, Nouws HP, Delerue-Matos C (2019) Electrochemical sensing platforms for HER2‐ECD breast cancer biomarker detection. Electroanalysis 31(1):121\u0026ndash;128\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang X, Chen P, Zhang X, Zhou H, Song Z, Yang W, Luo X (2023) An electrochemical biosensor for HER2 detection in complex biological media based on two antifouling materials of designed recognizing peptide and PEG. Anal Chim Acta 1252:341075\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBezerra G, C\u0026oacute;rdula C, Campos D, Nascimento G, Oliveira N, Seabra MA, Visani V, Lucas S, Lopes I, Santos J (2019) Electrochemical aptasensor for the detection of HER2 in human serum to assist in the diagnosis of early stage breast cancer. Anal Bioanal Chem 411:6667\u0026ndash;6676\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmir H, Subramanian V, Sornambikai S, Ponpandian N, Viswanathan C (2024) Nitrogen-enhanced carbon quantum dots mediated immunosensor for electrochemical detection of HER2 breast cancer biomarker. Bioelectrochemistry 155:108589\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen D, Wang D, Hu X, Long G, Zhang Y, Zhou L (2019) A DNA nanostructured biosensor for electrochemical analysis of HER2 using bioconjugate of GNR@ Pd SSs\u0026mdash;Apt\u0026mdash;HRP. Sens Actuators B 296:126650\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Scheme 1","content":"\u003cp\u003eScheme 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"advanced-composites-and-hybrid-materials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"achm","sideBox":"Learn more about [Advanced Composites and Hybrid Materials](https://link.springer.com/journal/42114)","snPcode":"42114","submissionUrl":"https://submission.nature.com/new-submission/42114/3","title":"Advanced Composites and Hybrid Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Aptamer, HER2, MXene nano-layer, Hybrid composite, Biosensor","lastPublishedDoi":"10.21203/rs.3.rs-4399330/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4399330/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis research work explores the development and application of layer-by-layer modified electrochemical apta-sensor for the precise monitoring of HER2, a crucial biomarker associated with breast cancer. The surface of the screen-printed carbon electrode was modified with gold nanoparticle (Au-NP) and TiVC MXene catalyst plus Pb\u003csup\u003e2+\u003c/sup\u003e loaded aptamer (SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer), which showed a high selectivity and affinity toward HER2 and offered a sensitive detection platform. The MXene nano-layer was synthesized and characterized by FT-IR, MAP, EDS, and TEM methods and used as a substrate to improve electrochemical conductivity and loading of biological recognition element. The difference of stripping signals of the Pb\u003csup\u003e2+\u003c/sup\u003e from the SPCE/TiVC-MXene/Au NPs/Pb\u003csup\u003e2+\u003c/sup\u003e-aptamer before and after incubation in HER2 solution was selected as analytical response to achieve a reliable and quantitative analysis for HER2 concentrations. The results demonstrate a linear dynamic range of 1.0\u0026ndash;1200 pg/mL for monitoring of HER2 with limit of detection of 50 fg/mL. Agood affinity of fabricated aptasensor to HER2 in the presence some other biomarkers such as PR, ER, and CEA confirmed the selectivity of the fabricated biosensor towards HER2.\u003c/p\u003e","manuscriptTitle":"Enhanced detection of HER2 through a layer-by-layer strategy using a TiVC MXenes/Au nanocomposite amplified analytical biosensor for precise cancer biomarker monitoring","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-10 09:36:41","doi":"10.21203/rs.3.rs-4399330/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-04T19:41:16+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-31T17:21:56+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-31T11:25:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"188619613399034735093178841911786819529","date":"2024-05-30T15:03:33+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-30T07:43:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"195775753562740034426540890132234787087","date":"2024-05-28T13:22:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"65816331542749717727736102164255725970","date":"2024-05-28T09:24:48+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-28T09:21:25+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-28T09:17:07+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-05-28T06:40:58+00:00","index":"","fulltext":""},{"type":"submitted","content":"Advanced Composites and Hybrid Materials","date":"2024-05-10T08:32:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"advanced-composites-and-hybrid-materials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"achm","sideBox":"Learn more about [Advanced Composites and Hybrid Materials](https://link.springer.com/journal/42114)","snPcode":"42114","submissionUrl":"https://submission.nature.com/new-submission/42114/3","title":"Advanced Composites and Hybrid Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"596bdfed-316b-469c-aacd-b00286399927","owner":[],"postedDate":"June 10th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-07T16:06:49+00:00","versionOfRecord":{"articleIdentity":"rs-4399330","link":"https://doi.org/10.1007/s42114-024-00966-8","journal":{"identity":"advanced-composites-and-hybrid-materials","isVorOnly":false,"title":"Advanced Composites and Hybrid Materials"},"publishedOn":"2024-10-02 15:57:20","publishedOnDateReadable":"October 2nd, 2024"},"versionCreatedAt":"2024-06-10 09:36:41","video":"","vorDoi":"10.1007/s42114-024-00966-8","vorDoiUrl":"https://doi.org/10.1007/s42114-024-00966-8","workflowStages":[]},"version":"v1","identity":"rs-4399330","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4399330","identity":"rs-4399330","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}