Augmenting adhesion strength and biomimetic properties of polymeric nanocomposite coatings on titanium implants

Augmenting adhesion strength and biomimetic properties of polymeric nanocomposite coatings on titanium implants | 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 Augmenting adhesion strength and biomimetic properties of polymeric nanocomposite coatings on titanium implants Suja Mathai, Priyanka S Shaji, Sandhya K S, Limitha Chandran This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7829417/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Nano-HAp can more easily cause apatite to precipitate on the surface of Ti when combined with poly vinyl alcohol (PVA) and collagen peptide (Collg) coating. The properties of PVA include good adhesion and strong corrosion resistance. In this study, HAp reinforced with collagen peptide nanopowders and PVA nanocrystals was generated using the electrodeposition technique. The in vitro bioactivity of the HAp-Collg-PVA nanocomposite coatings performed in Kokubo's simulated bodily fluid without being subjected to an alkaline treatment. To assess the coatings bioactivity, adhesion power, and corrosion resistance, they were subjected to a variety of physical and electrochemical characterization techniques under physiological conditions. By using the techniques of fourier-infrared spectroscopy (FT-IR), x-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and atomic force microscopy (AFM), it was determined how PVA with Collg as reinforcement affected the structure of nanocomposite coating with HAp on the surface of Ti. Computational studies suggests that Collg interacts with HAp (-6.08 kcal/mol) better than with polyvinyl alcohol (-2.09 kcal/mol). The nanocomposite coatings porosity, hydrophilicity, mechanical stability and adhesion strength were also investigated. PVA and Collg combined with HAp improved bioactivity, corrosion resistance, and adhesion strength. The biomimetic properties this component in this nanocomposite offers a functional platform for promoting osseointegration and improving implant longevity. Electrodeposition nanocomposite coating polyvinyl alcohol titanium osseointegration Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1 Introduction Commercially available pure titanium (CP-Ti) has been widely used as an implant material in orthopedic prosthesis because of its excellent biocompatibility, low weight, adequate load-bearing capacity, and superior corrosion resistance [ 1 , 2 ]. To promote bioactivity and enhance bone integration, the surface of titanium implants can be improved and accelerated by the presence of a calcium phosphate (CaP), an important component of bone mineral especially hydroxyapatite [HAp: Ca 10 (PO 4 ) 6 (OH) 2 ] [ 3 ]. HAp is a crucial component for biomedical implants since it resembles real bone in terms of structure, chemistry, and biology [ 4 ]. However the inherent brittleness, poor mechanical strength, and limited adhesion to metallic substrates like Ti restrict its long-term stability and functionality as standalone coating for orthopedic implants. To address these limitations, nanocomposite strategies incorporating organic polymers have been adopted. Among several choices of polymers, polyvinyl alcohol (PVA), is one of the more widely used polymers because of its excellent mechanical properties. is reinforced with HAp and collagen peptide due to its biocompatible, nontoxic, non-carcinogenic, and bio-adhesion characteristics [ 5 ]. known as synthetic hydrophilic polymer can interact with metals resulting to improve the surface characterization and mechanical integrity. Additionally, PVA is utilized to coat implant material because of its capacity to osseointegrate in host bone tissue and its most advantageous qualities, which include corrosion resistance, thermal conductivity, and mechanical processability [ 6 – 8 ]. The excellent biological behaviors of calcium phosphate with collagen can accelerate bone growth and assist in fixation of titanium implants [ 9 , 10 ]. Collagen peptide (collagen type 1) is the most important component of extracellular matrix (ECM), and has shown perfect biocompatibility, stimulate bone cell adhesion, cell, and biomineralization [ 11 , 12 ]. The biological properties of collagen peptide play decisive roles in protein absorption, cell adhesion and growth [ 13 , 14 ]. The advantages of electrodeposition (ED), which can be done at room temperature, include low cost, ease of use, uniformity of deposition, control over deposition thickness, micro-structural homogeneity, the capacity to coat complexly shaped substrates and the potential to coat porous substrates, easy parameter control [ 15 ], quick preparation time, basic equipment, and ease of operation [ 16 ]. Understanding the ED process may agree to successfully fabricate highly bioactive coatings for quick bone growth. The present work aims to control and improve the structure, bioactivity and adhesion strength of HAp reinforced with PVA and collagen peptide (Collg) to form nanocomposite coatings on Ti orthopedic implants by the application of ED process that mimics the natural bone extracellular matrix. Nano-meter sized HAp and HAp-Collg-PVA nanocomposite coatings are synthesized, characterized and electrochemically coated on the surface of Ti substrates and the coated samples were dried at room temperature. The uniform and un-cracked coatings with the high adhesion strength is formed on the Ti substrate is selected and tested for its biological performance. Understanding the ED process may agree to successfully fabricate bioactive and adhesive coatings for quick bone growth. This study seeks to enhance the interfacial bonding of Ti substrates to support bone tissue integration and long-term implant success in orthopedic applications. 2 Materials and methods 2.1 Materials For the coating, commercially available pure Ti specimens (Grade T3160) of area 2 × 1 cm 2 and 1 mm thickness, purchased from Sigma Aldrich (Germany) were used. PVA (99%, Sigma Aldrich, Germany), and collagen peptide (Mw ~ 300000 g mol-1, Hydrolyzed form of collagen type 1, HIMEDIA, India) were used as the raw materials. For in vitro studies, calcium nitrate tetrahydrate, Ca(NO 3 ) 2 .4H 2 O (99%, Spectrum, India), ammonium dihydrogen orthophosphate, NH 4 H 2 PO 4 (99%, Rankem, India), sodium hydrogen carbonate (purified), NaHCO 3 (99%, Merk, India), dipotassium hydrogen orthophosphate, K 2 HPO 4 (99.9%, Fisher Scientific, USA), magnesium chloride, MgCl 2 .6H 2 O (99%, Nice, India), calcium chloride dehydrate, CaCl 2 .2H 2 O (99%, Fisher Scientific, USA), sodium sulphate anhydrous A.R., Na 2 SO 4 (99%, Merk, India), tris buffer A.R., (CH 2 OH) 3 CNH 2 (99%, Spectrum, India), sodium hydroxide pellets A.R. (99%, SRL, India) were used. 2.2 Electrodeposition (ED) Ti substrates were etched with equal volumes of conc. HNO 3 and 30% H 2 O 2 for 1hr. After that, the strip was cleaned with distilled water and allowed to dry for 30 minutes (mins) at room temperature. The electrodeposition carried out in a three- electrochemical cell, the etched strip act as working electrode i.e., cathode and the platinum (Pt) mesh act as counter electrode (anode) and a standard calomel electrode act as reference electrode. After pretreatment, the ED was carried out in an electrolytic solution containing Ca(NO 3 ) 2 and NH 4 H 2 PO 4 . To the electrolyte, 0.02g of Collg and 0.05g of PVA are added. The initial pH of the solution obtained was 3.2 and was adjusted to 5.5 using a pH meter by adding 2M NaOH [ 17 ] for the codeposition of PVA and collagen peptide. The deposition was carried out for 1 hour at a temperature of 80 o C under constant current density 1.5 mA/cm 2 and a potential of 1.5-2V respectively [ 18 ]. After the ED of the coating, the coated substrates were taken out and dried at room temperature. 2.3 Physico-chemical and surface characterization X-ray diffraction (XRD, Bruker D8 ADVANCE with DAVINCI design) was performed to determine the phase purity of the synthesized material. The chemical functional groups were characterized by fourier-transform infrared spectroscopy (FTIR, Thermoscientific Nicolet iS50). Scanning electron microscope (SEM, Carl Zeiss EVO 18 Research) coupled with energy dispersive spectroscopy (EDS, Carl Zeiss EVO 18 Research) were carried for the surface microstructural morphology analyses. Atomic force microscopy (AFM), Nanosurf Flex-ANA instrument was determined for the surface roughness morphology of the coatings. 2.4 Electrochemical investigation The electrochemical properties of HAp-Collg-PVA nanocomposite coatings on titanium (Ti) substrates were investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in a 0.9% NaCl solution. The experiments were carried out in a standard three-electrode setup, with a saturated calomel electrode (SCE) as the reference electrode, a platinum (Pt) electrode as the counter electrode, and the Ti substrate serving as the working electrode for all measurements. All electrochemical analyses were conducted using a Metrohm Autolab PGSTAT204 workstation. 2.5 In vitro bioactivity study The in vitro bioactivity of the developed coatings can be studied in Kukubo’s simulated body fluid (SBF) at 20 days at 36.5oC and pH 7.4 [ 19 ]. The SBF solution was prepared by dissolving the required amount of reagent-grade chemicals of NaCl, NaHCO 3 , KCl, K 2 HPO 4 . 3H 2 O, MgCl 2 . 6H 2 O, HCl, CaCl 2 , Na 2 SO 4 in distilled water and buffered to pH using a solution of tris-hydroxylmethyl aminomethane ((CH 2 OH) 32 ) [ 20 , 21 ]. The surface morphology and elemental composition of the coatings before and after bioactivity study was analyzed microscopically and spectroscopically. 2.6 Computational methodology The 3D structures of the protein were downloaded in PDB format from the Protein Data Bank (PDB), and it’s PDB ID is 2LLP. The chemical structure of Poly vinyl alcohol (CID:11199) and HAp (CID:14781) ligand were obtained from the PubChem in SDF format. HAp is 2D formate hence, we changed it into 3D form and the structure was optimized using B3LYP DFT method and 6-31G(d,p) basis set. DFT calculation is implemented in Gaussian software 09W [ 22 ]. The downloaded protein is opened in Discovery Studio to remove water molecules, ions, solvents, etc present in the systems. Docking calculation was performed using AutoDock 4.2 [ 23 ]. Pymol was used for the visualization of these structures. 3 Result and discussion 3.1 Surface and physio-chemical characterization 3.1.1 Porosity To regulate the essential functions of nutrition delivery to cells, metabolic dispersion, local pH stability, and cell signaling, the scaffold must have the right amount of porosity. Smaller holes limit the ability of cells to seed in the center of the scaffold and feed on its inner surfaces, while larger pores impact the scaffolds stability and capacity to offer the seeded cells physical support. Cells can migrate or stick to the surface of materials when pores are large enough[ 24 ]. The porosity of the CaP coating and the CaP-Collg-PVA nanocomposites coatings was above 42% and 66%, respectively, as shown in Table 1 , suggesting that they were appropriately porous and advantageous for cell adhesion and proliferation. The fact that the number of nanofiber mat layers in the scaffold is connected with the porosity of various surface layers, the CaP-Collg-PVA nanocomposite coating demonstrated higher porosity at 66% than the other two coatings[ 25 ]. Increasing porosity lowers the chance of implant failure, promotes bone and cell formation. It was discovered that the pore sizes of the CaP, and CaP-Collg-PVA, nanocomposite coatings were 80 ± 2.7, 86 ± 3.8, and 90 ± 1.9 µm, respectively. Small pores and high porosity can promote bone cell differentiation and development, improving implant stability and osseointegration. Table 1 Porosity and pore size of the CaP coating, and CaP-Collg-PVA nanocomposite coatings on Ti substrates S. No. Samples Porosity (%) Pore size (µm) 1 CaP 42 80 ± 2.7 2 CaP-Collg-PVA 66 86 ± 3.8 3.1.2 Vickers microhardness test For bio-implants, the hardness test findings are essential because they demonstrate how effectively the implants will support weight when subjected to stress in the human body. CaP, and CaP-Collg-PVA, nanocomposite coating Vickers microhardness results on Ti specimens under varied applied stresses are displayed in Fig. 1 . With an increase in applied stresses, it was discovered that the microhardness values rise. Under all applied loads, the CaP-Collg-PVA nanocomposite coating demonstrated a greater microhardness value than both CaP coating during the testing. These coatings demonstrated stability at 50 gf of applied stress, with microhardness (HV) values of 198.4 ± 0.7 and 287.2 ± 0.9 HV for CaP, and CaP-Collg-PVA coatings, respectively. As a result, the surface of CaP-Collg-PVA on Ti substrates would have an ideal concentration of Collg and PVA, strengthening the binding and enhancing the bio-mechanical stability of the CaP. 3.1.3 Contact Angle Analysis Wettability plays a key role in a material’s biological performance. By measuring their contact angle, the hydrophilicity of the CaP coating, and CaP-Collg-PVA, nanocomposite coating on Ti metal strip is demonstrated in Fig. 2 . With a contact angle of 84.72o, the Ti substrate is hydrophilic, which enhances the materials biological properties, such as its bone-bonding behavior and bioactivity[ 26 ]. Furthermore, the CaP coating, and CaP-Collg-PVA nanocomposite coating have hydrophilic contact angles of 72.35 ± 0.08o (water); 79.28 ± 0.02o (NaCl), and 56.35 ± 0.10o (water); 62.68 ± 0.09o (NaCl). The hydrophilic properties of these materials, particularly CaP-Collg-PVA nanocomposite coatings, are advantageous for their possible use in orthopaedic implants. 3.1.4 Adhesion strength For a Ti specimen to function correctly under physiological environments, the coatings adhesion strength is crucial. Figure 3 displays the CaP, and CaP-Collg-PVA, nanocomposite coatings adhesion strengths to Ti metals. Accordingly, the adhesion strengths of the CaP and CaP-Collg-PVA coated on Ti metal are 12.4 ± 0.8, 29.3 ± 0.9, and 32.1 ± 0.8 MPa. The CaP-Collg-PVA nanocomposite coatings enhanced adhesion strength is a result of the PVA coated layers greater chemical affinity for Ti[ 27 ]. This shows strong adhesion between CaP, Collg, and PVA ensures a stable nanocomposite structure that resists physiological stresses, promotes bone cell attachment and growth, and improving durability in the harsh environment of the human body. 3.1.5 Scanning electron microscopy (SEM)/ Energy dispersive spectroscopy (EDS) SEM micrograph and associated EDS pattern of the HAp and HAp-Collg-PVA nanocomposite coatings electrodeposited on etched Ti substrate, performed in both before and after subsequent soaking in SBF for 20 days are presented in Fig. 4 . The broad petal-like crystallites of the HAp coating on Ti are seen in Fig. 4 (a). The SEM and EDS images of the HAp coating on the Ti substrate after 20 days of immersion in the SBF solution are displayed in Fig. 4 (b). On the coated surface, the evenly dispersed apatite crystals are readily visible. The presence of HAp component elements including Ca, P, O, and Mg may be identified by EDS analysis, as shown in Fig. 4 (a) and (b). The electrodeposited HAp-Collg-PVA nanocomposite coatings over the etched Ti substrate, which contains petal-like cyrstallites with apatite crystals produced, are depicted in Fig. 4 (c) [ 28 ]. Figure 4 (d) shows the apatite, which was found to be more compact and denser and evenly distributed over the surface of the HAp-Collg-PVA nanocomposite coating on etched Ti that was submerged in SBF for 20 days. Figure 4 (c) and (d) reveal the elemental components as Ca, P, O, and Mg correspond to HAp, whereas elemental C and N are caused by PVA or maybe by the amino acid residues in collagen peptide, which are verified by the EDS. The Ca 2+ ion aggregate on the metal surface after 20 days of immersion in SBF, gradually gaining a positive charge. In order to create crystalline calcium phosphate, the positively charged surfaces interact with the negatively charged phosphate ions. Magnesium (Mg) is also formed along with calcium and phosphate ions, which plays a significant role in bone ingrowth since the natural bone contains 60% of the total magnesium. The Ca 2+ and PO 4 3− ions in the SBF are consumed by the generated apatite nuclei as they develop spontaneously. As Ca 2+ and PO 4 3− ions formed, the EDS data showed that the HAp-Collg-PVA particles had a Ca/P ratio of 1.65, which is close to real bone and causes osseointegration. When the HAp-Collg-PVA nanocomposite coated Ti substrate is embedded in SBF, it is discovered to be uniformly deposited on the surface, with just a few surface-level pores and no significant apparent fractures. As previously indicated, this conclusion is consistent with the research conducted by Degirmenbasi et al and Rusu et al [ 29 , 30 ]. From data it shows the SEM- EDS images of HAp-Collg-PVA nanocomposite coating on Ti substrate immersed in SBF for 20 days at 36.5oC shows that the HAp particles were uniformly distributed in the PVA matrix with no apparent of agglomeration, which indicates the formation of mechanical and biological performance of reinforced nanocomposite coating [ 31 ]. This resulted from the presence of PVA and the addition of collagen peptide to the PVA matrix, indicating that PVA is essential for the creation of apatite nuclei during sample incubation in SBF solution. This further supports the ability of nanocomposite coatings to promote bone ingrowth. EDS spectra verify that components including Ca, P, O, and Mg are present in the HAp-Collg-PVA nanocomposite. The composite coatings Ca/P atomic ratio, however, increases after 20 days of immersion, demonstrating that the apatite layer forms on the nanocomposites surface more quickly. According to Kukubo et.al [ 32 ], negatively charged ions' surface functional groups affect their electrostatic interactions with SBF ions and cause the production of apatite. By drawing Ca2 + ions from SBF solution, the OH group of PVA may create a strong intermolecular hydrogen bond with the OH- and PO43- of HAp-Collg-PVA nanocomposite coatings, starting the nucleation of apatite and resulting in the development of stable bonelike apatite [ 33 ]. From the observe data the rate of apatite precipitation was more on the surface of HAp-Collg-PVA as compared to HAp nanocomposite coating on Ti substrate possess both favorable mechanical and bioactive properties. 3.1.6 Atomic force microscopy (AFM) The coatings morphology and roughness were assessed using a 1 µm scan size. HAp-Collg-PVA nanocomposite coating on Ti is seen to be agglomerated with non-uniform morphology, with a surface diameter of 40 nm, according to a 3D AFM picture displayed in Fig. 5 (a). As shown in Fig. 5 (b), the HAp-Collg-PVA coated substrate exhibited consistent apatite formation with a surface diameter of 60 nm following 20 days of immersion in SBF. HAp-Collg-PVA nanocomposite coating (Fig. 5 (a)) has an average roughness (Ra) of 0.758 nm and a root mean square roughness (Rq) of 1.091 nm. Similarly, the HAp-Collg-PVA nanocomposite coating in Fig. 5 (b) shows a rough morphology with a root mean square roughness (Rq) of 28.142 nm and an average roughness (Ra) of 22.219 nm following a 20-day soak in SBF. The presence of PVA and collagen peptide in the HAp matrix may raise electrical signals to form bioactive nanocomposite coating on Ti substrate. Increasing the coated substrates roughness enhances cell adhesion and osseointegration[ 34 ]. The thickness of the nanocomposite coating can be analyzed form the 3D image of AFM and it is confirmed from Fig. 5 (a) and (b) the thickness off the coating formed is approximately 3 µm. The AFM images of HAp-Collg-PVA nanocomposite coating on Ti immersed in SBF for 20 days showed relatively increased surface roughness leads to more uniform coverage compared to the one formed with HAp-Collg-PVA coating on Ti. It has found that, a higher surface roughness increases the adhesion of cells[ 35 ]. It has been demonstrated that excess HAp particles do not distribute well within the PVA, readily weakening the interaction between HAp and PVA[ 36 ]. Apparently, it was observed that collagen peptide in PVA matrix provides a better cellular response such as adhesion, proliferation and differentiation with favorable surface roughness as well as mechanical strength with characterized physiochemical properties[ 37 ]. Studies have shown that strength-enhanced HAp-Collg-PVA nanocomposite coating may be good substitutes for the Ti substrates. 3.1.7 X-ray diffraction (XRD) XRD analysis was used to investigate the crystallinity and phase content of the HAp and HAp-Collg- nanocomposite coating on Ti are shown in Fig. 6 (a) and (b). In Fig. 6 (a), the prominent peaks of the HAp nanocomposite coating on Ti that resulted at 2θ = 20.414o, 25.26o, 31.92o, 33.11o, 40.66o, and 44.59o are features of hydroxyapatite. According to the standard JDPDS card 09-0432 file, the observed diffraction peaks show a highly crystalline form of HAp[ 38 ]. Secondary phases like TCP and TTCP were not found. In Fig. 6 (b), the characteristic peaks corresponding to 2 = 20.49o, 22.99o, 28.8o, 32.04o 45.21o, 45.56o, 49.29o revealed the relative strong diffraction peak of HAp-Collg-PVA nanocomposite coating. The peaks appeared at 2 = 23.90o, 32.04o corresponds to the formation of HAp and the characteristic peaks at 2 = 20.49o indicates non- crystalline behavior of PVA[ 39 ] after reinforced with HAp and Collg. The XRD studies revealed that the major phase of HAp-Collg-PVA nanocomposite coatings, the ceramic and polymer both exhibit crystalline behavior in the composite covering, suggesting a negligible alteration in their crystal structures. Similar to real bone, where HAp is equally distributed in the PVA and collagen peptides, this further supports the idea that HAp is finely and uniformly increased in the matrix[ 40 , 41 ]. A very weak and broad peak indicates the non-crystalline behavior of PVA by the incorporation of HAp is due to poor dispersion of HAp in PVA solution. 3.1.8 Fourier transform infrared (FTIR) spectroscopy Figure 7 (a) and (b) depicts the FTIR spectra of HAp and HAp-Collg-PVA nanocomposite coatings on Ti. The phosphate ions are responsible for the absorption bands at 574.01, 656.63, 982.81, 1051.29, and 1116.64 cm-1 seen in the spectra, whereas the carbonate ions of the apatite phase were responsible for the faint peak at 1645.25 cm-1 in Fig. 7 (a). The peaks at 3472.57 and 3532.92 cm-1 corresponds to O-H absorption stretching bands of HAp[ 42 , 43 ] The FTIR spectra of HAp-Collg-PVA coatings represent peaks at 574.38, 657.03, 982.20, 1051.49, 1116.58 cm-1 establishes the presence of phosphate ion in HAp are shown in Fig. 7 (b). The band located at 869.75 cm-1 is associated with the C = C stretching vibration and the C-H out-of-plane vibration of PVA or collagen peptide. Absorption peak around 2980.58 cm-1 originates from the C-H stretching vibration and C-H-wagging vibration in the alkyl groups on the PVA and the absorption bands at 1395.70 cm-1 illustrates the presence of carbonyl group of HAp. The following peaks in the spectra were identified as characteristic peaks of PVA: a wide (O-H) absorption stretching band at 3471.99, 3533.01 cm-1, which showed the existence of polymeric connection of the free hydroxyl groups and bound O-H vibration. The peaks of FTIR confirm the existence of phosphate ions, stretching and bending modes of the O-H groups in the HAp-Collg-PVA nanocomposite coatings on Ti substrate. The presence of (O-H) stretching band indicating the presence of polymeric association of the free hydroxyl groups and bonded O-H stretching vibration and C-H interaction in the alkyl groups is due to PVA backbone[ 44 , 45 ]. The presence of the carbonate ion results from the interaction between atmospheric carbon dioxide and the nano-HAP precursor alkaline solution sample, this reaction has been seen in other studies too[ 46 ]. 3.2 Electrochemical investigation 3.2.1 Electrochemical impedance spectroscopy (EIS) Figure 8 and 9 display the EIS Nyquist impedance plots and the circuit diagram, respectively, for (a) HAp and (b) HAp-Collg-PVA nanocomposite coating on Ti submerged in 0.9% NaCl solutions. The solution resistance, as determined by the data, is RS, the constant phase elements (CPEs) are Q, the polarization resistance, which indicates the resistance between the Ti substrate and a corrosion product layer is RP1, and the second polarization resistance, which represents the resistance between the corrosion product and solution interface, is RP2[ 47 ]. It is seen from Fig. 8 , that both HAp and HAp-Collg-PVA coated specimen showed only half semicircle and the diameter of the semicircle is wider for HAp-Collg-PVA than HAp. The parameters listed in Table 1 showed that the values of the resistances, RS, RP1 and RP2 for HAp-Collg-PVA nanocomposite coating recorded higher values compared to the HAp coating on Ti. The EIS measurements thus confirm that HAp-Collg-PVA showed better corrosion resistance and adhesion strength than HAp. The Nyquist curves (combined) obtained plot of the HAp and HAp-Collg-PVA coated specimen showed a bigger diameter for the semicircle than the HAp coated specimen due to the increased surface passivation by PVA. The presence of PVA on the Ti surface thus increase the impedance of Ti through increasing its surface passivation. It is also noted that the diameter of the semicircle increases with inhibitor concentration resulting an increase in corrosion resistance of the material[ 48 ]. It is obvious from the results that HAp-Collg-PVA coating inhibits the enhancement of the corrosion protection properties of Ti substrate. Table 2 The electrochemical impedance parameters. S. no Material R S R P1 R P2 1 HAp coated Ti -14.409 29.857 6966.7 2 HAp/Collg/PVA coated Ti -21.065 34.052 9998.7 3.2.2 Cyclic voltammetry (CV) HAp coating and HAp-Collg-PVA nanocomposite coating on Ti substrate in 0.9% NaCl solution were measured for current and working electrode potential at a scan rate of 0.01 V s-1 to produce the cyclic voltammograms that are displayed in Fig. 10 (a) and (b). HAp coating nucleation on the Ti surface is demonstrated by Fig. 10 (a), which exhibits a reduction potential peak at -0.6 V with an increasing current density from − 5×10 − 4 to 2.7×10 − 3 A. In Fig. 10 (b), a reduction potential for HAp-Collg-PVA nanocomposite coating with a current density ranging from − 1×10 − 3 to 2.8×10 − 3 A at -0.75 V is displayed. The higher the potential applied, the lower the current density. The reduction peak was found on both the graphs but more reduction peak was prominent on HAp-Collg-PVA coating shows the coating does not undergo or very less delamination compared to the HAp coating results in high corrosion resistance and adhesion strength of the coating. The nature of electrode reactions can often be determined based on the peak current in cyclic voltammetry (CV). In contrast to HAp coating on Ti, the desired potential range of a suitable HAp-Collg-PVA nanocomposite coating on Ti substrate via electrodeposition was created based on these findings, which showed a plateau in current density. The addition of PVA and collagen peptide significantly improved the adhesive strength of the coating and corrosion. The more anodic behaviour of the HAp-Collg-PVA coatings showed the stability of the coating. As more PVA particles are formed on the substrate, the electrodes surface charge exchange rate improves, which explains why the current rises as the voltage does [ 49 ]. 3.3 Computational Studies In our study, structures such as Collg, HAp, and PVA are used for blind molecular docking to investigate the interactions of a Collg with these compounds. The optimized structures are given in the SI. Blind docking was useful in this research since the specific binding site on the Collg was unknown, which allowed us to perform an unbiased search for potential interaction regions. The structures were taken as input for docking simulations carried out. The binding energies derived from the docking study were − 6.08 kcal/mol for the Collg–HAp complex and − 2.09 kcal/mol for the Collg–PVA complex. The higher negative binding energy with HAp indicates stronger and better interaction relative to polyvinyl alcohol. The non-covalent interactions, like hydrogen bonds and van der Waals contacts, were observed. One can see that residues GLN15 and GLY16 of collagen interact with Ca of HAp with distances of 2.2 Å and 3.3 Å, respectively in Fig. 11 (a). While residue ALA18 interacts with O of one of the PO4 via hydrogen bonding. The hydrogen and oxygen of the hydroxyl group interact with two GLN15 from two chains of collagen via one hydrogen bond. PVA makes two hydrogen bonds with GLY19 and GLN20 of two different chains of collagen shown in Fig. 11 (b). These observations provide evidence for the possibility of HAp being a better binding partner for collagen peptides, and this can be pertinent to biomaterial design and tissue engineering. 4 Conclusions In the present work, we have successfully fabricated the electrodeposited HAp-Collg-PVA nanocomposite coating on Ti substrate. The XRD and FTIR analysis confirms that the reinforcement of PVA matrix with collagen peptide and HAp, the crystallinity and the intensity of sharp bands found to be increased. The electrochemical treatment could be an effective method for the stability and corrosion resistance of pure Ti substrate. The SEM analysis reveals the surface morphology of nanocomposite coatings confirms that appropriate distribution of apatite on the surface of Ti substrate. The EDS measurements revealed a higher concentration of protein in the HAp-Collg-PVA nanocomposite coating as compared with the HAp coating on Ti. By SEM, AFM, EIS and CV were possible to study the initial stage of the hydroxyapatite presence because this specific technique allows detecting the electrochemical and deposition processes separately. Molecular docking studies reveal that HAp binds with Collg more effectively than with PVA, which suggests that better binding partner for collagen peptides. The HAp-Collg-PVA nanocomposite coating became biologically active without alkaline treatment and favored apatite growth reveals highly bioactive and adhesive Ti implants. HAp alone mimics the mineral phase of bone, the incorporation of Collg introduces biomimetic cues that promote cell adhesion, while PVA improves mechanical stability and homogeneous dispersion of the nanocomposite. Together, HAp-Collg-PVA nanocomposite coating on Ti implants may be excellent substitutes for the physical-chemical interaction of bone implant, thus results in improved bioactivity, cytocompatibility, and potential for strong bone-implant integration. This study proves a promising approach for creating bifunctional surfaces that support the long-term success of Ti-based orthopedic implants. Declarations Conflict of Interest The author declares no conflict of interest. Orchid iDs Suja Mathai https://orcid.org/0000-0002-0614-2742 Priyanka S Shaji https://orcid.org/0000-0001-8742-8437 Sandhya K S https://orcid.org/0000-0002-3628-0521 Limitha Chandran M C https://orcid.org/0009-0007-7763-406X Author Contribution Author Contribution StatementType of contribution ContributorsConcept and design Dr. Suja Mathai, Ms. Priyanka S ShajiData acquisition Ms. Priyanka S ShajiData analysis / interpretation Ms. Priyanka S Shaji, Dr. Sandhya K SDrafting manuscript Ms. Priyanka S ShajiCritical revision of manuscript Dr. Suja MathaiStatistical analysis Ms. Priyanka S Shaji, Dr. Sandhya K SAdmin, technical or material support Dr. Suja Mathai, Priyanka S Shaji, Dr. Sandhya K S, Limitha Chandran M CSupervision Dr. Suja MathaiFinal Approval Dr. Suja Mathai Acknowledgements The Central Laboratory for Instrumentation and Facilitation, Biovent Pvt. Ltd., University Campus, Karyavattom, is acknowledged by the authors for its assistance with the biological, XRD, FTIR, and SEM-EDS investigations. For assistance with the adhesion strength, contact angle measurements, and microhardness test, we are grateful to the CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India. Additionally, the EIS, CV, and AFM investigations of the coated surface were made possible by the assistance of ICAR-Central Institute of Fisheries Technology (CIFT), Kochi. Data Availability Statement All data that support the findings of this study are included within the article. Computational part is included in supporting information. References N. Moritz, S. Areva, J. Wolke, T. Peltola, TF-XRD examination of surface reactive TiO₂ coatings produced by heat treatment and CO₂ laser treatment. Biomaterials. 26 , 4460–4467 (2005). https://doi.org/10.1016/j.biomaterials.2004.11.020 S. Lin, R.Z. LeGeros, J.P. 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10:03:37","extension":"html","order_by":31,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":146555,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/4ae7fb74e06a9b78ae14de74.html"},{"id":96264463,"identity":"d010aa84-5fd5-4332-b726-f2345a41e9f0","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":45429,"visible":true,"origin":"","legend":"\u003cp\u003eMicrohardness of CaP coating, and CaP-Collg-PVA nanocomposite coatings on Ti substrates for various loads. Data = Mean ± SD\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/4f7056d8f15e34c83fed25ce.png"},{"id":96264464,"identity":"17210579-efd8-4603-b519-2a3e87ed8652","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":29253,"visible":true,"origin":"","legend":"\u003cp\u003eContact angle measurement recorded for CaP coating, and CaP-Collg-PVA nanocomposite coating on Ti substrates, (a) Water; (b) NaCl. Data = Mean ± SD\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/1ecfb9d14787fc27a3886898.png"},{"id":96364173,"identity":"de7f93e3-ee7e-447e-8a86-b71d401a3491","added_by":"auto","created_at":"2025-11-20 10:09:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":17878,"visible":true,"origin":"","legend":"\u003cp\u003eAdhesion strength of CaP coating, and CaP-Collg-PVA nanocomposite coating on Ti substrates. Data = Mean ± SD\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/67460b69d999e0a11b8679db.png"},{"id":96264474,"identity":"04ee3068-e407-4db8-98ce-f13d1327c95a","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1980851,"visible":true,"origin":"","legend":"\u003cp\u003eSEM of (a) HAp coating, (b) HAp coating on Ti substrate immersed in SBF at pH 7.4 and 36.5oC for 20 days (c) HAp-Collg-PVA nanocomposite coating on Ti substrate (d) HAp-Collg-PVA nanocomposite coating soaked in SBF at pH 7.4 and 36.5\u003csup\u003eo\u003c/sup\u003eC for 20 days\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/c19a653e18f8998fd44ae745.png"},{"id":96264468,"identity":"ec704d48-5391-4e77-818b-5298c6c4ee3e","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1307050,"visible":true,"origin":"","legend":"\u003cp\u003eAFM images of (a) HAp-Collg-PVA coating on Ti substrate and (b) HAp-Collg-PVA coatings soaked in SBF at pH 7.4 and 35.5\u003csup\u003eo\u003c/sup\u003eC for 20 days\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/73da6f0f35013d481a1c69da.png"},{"id":96264470,"identity":"2a7429ab-3957-4c3d-a291-62bf449fbe82","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":32680,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of (a) HAp and (b) HAp-Collg-PVA nanocomposite coatings on Ti substrate\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/52d587411ce7e2a40c4aef45.png"},{"id":96264471,"identity":"b63ab2e3-fbe5-45da-8966-86212f0100a4","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":76489,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra analysis of (a) HAp coating and (b) HAp/Collagen/PVA nanocomposite coatings on Ti substrate.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/f0c03c78addc71a837cb299e.jpg"},{"id":96363634,"identity":"046d24d4-2ea8-4cb4-9166-d4389057d702","added_by":"auto","created_at":"2025-11-20 10:07:35","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":97176,"visible":true,"origin":"","legend":"\u003cp\u003eEIS Nyquist plots obtained for (a) Hap coating and (b) HAp-Collg-PVA nanocomposite coating on Ti substrate in 0.9% NaCl solution\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/fe28fcfbadb1c029c139762d.png"},{"id":96363294,"identity":"841534b6-085c-4a24-8067-b4b52a0d296a","added_by":"auto","created_at":"2025-11-20 10:06:03","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":5207,"visible":true,"origin":"","legend":"\u003cp\u003eEIS Nyquist plots obtained for (a) HAp coating and (b) HAp/Collagen/PVA nanocomposite coating on Ti substrate in 0.9% NaCl solution.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/ef0760b7c6ef20cd8ff599f2.png"},{"id":96363287,"identity":"062714a7-8909-4980-992f-39bf13fb3e6a","added_by":"auto","created_at":"2025-11-20 10:06:02","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":112347,"visible":true,"origin":"","legend":"\u003cp\u003eCyclic voltammograms of (a) HAp coating and (b) HAp-Collg-PVA nanocomposite coating on Ti substrate in 0.9 % NaCl solution.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/df558a35c13e5b9e11ce30a7.png"},{"id":96363116,"identity":"96f82b8e-b440-4289-9569-4cce76d13c44","added_by":"auto","created_at":"2025-11-20 10:04:38","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":272570,"visible":true,"origin":"","legend":"\u003cp\u003eDocked structure of (a) HAp and (b) PVA. Ca is in red and (PO)4 is in cyan in the enlarged figure\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/77e2e3dff095565224a734a9.png"},{"id":97137357,"identity":"dffcbd28-5dbc-48c9-9ece-5a841f03e855","added_by":"auto","created_at":"2025-12-01 09:57:38","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4637138,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/dbfd0a86-0e22-498c-94fc-1de1999e5081.pdf"},{"id":96264466,"identity":"47dc8941-1e33-4f4b-979d-6a5ec346dff9","added_by":"auto","created_at":"2025-11-19 08:30:38","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":13301,"visible":true,"origin":"","legend":"","description":"","filename":"Supportinginformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-7829417/v1/4a09701f7d0c8c02dd58e7b3.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Augmenting adhesion strength and biomimetic properties of polymeric nanocomposite coatings on titanium implants","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eCommercially available pure titanium (CP-Ti) has been widely used as an implant material in orthopedic prosthesis because of its excellent biocompatibility, low weight, adequate load-bearing capacity, and superior corrosion resistance [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. To promote bioactivity and enhance bone integration, the surface of titanium implants can be improved and accelerated by the presence of a calcium phosphate (CaP), an important component of bone mineral especially hydroxyapatite [HAp: Ca\u003csub\u003e10\u003c/sub\u003e(PO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003e(OH)\u003csub\u003e2\u003c/sub\u003e] [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. HAp is a crucial component for biomedical implants since it resembles real bone in terms of structure, chemistry, and biology [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However the inherent brittleness, poor mechanical strength, and limited adhesion to metallic substrates like Ti restrict its long-term stability and functionality as standalone coating for orthopedic implants. To address these limitations, nanocomposite strategies incorporating organic polymers have been adopted. Among several choices of polymers, polyvinyl alcohol (PVA), is one of the more widely used polymers because of its excellent mechanical properties. is reinforced with HAp and collagen peptide due to its biocompatible, nontoxic, non-carcinogenic, and bio-adhesion characteristics [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. known as synthetic hydrophilic polymer can interact with metals resulting to improve the surface characterization and mechanical integrity. Additionally, PVA is utilized to coat implant material because of its capacity to osseointegrate in host bone tissue and its most advantageous qualities, which include corrosion resistance, thermal conductivity, and mechanical processability [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe excellent biological behaviors of calcium phosphate with collagen can accelerate bone growth and assist in fixation of titanium implants [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Collagen peptide (collagen type 1) is the most important component of extracellular matrix (ECM), and has shown perfect biocompatibility, stimulate bone cell adhesion, cell, and biomineralization [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The biological properties of collagen peptide play decisive roles in protein absorption, cell adhesion and growth [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The advantages of electrodeposition (ED), which can be done at room temperature, include low cost, ease of use, uniformity of deposition, control over deposition thickness, micro-structural homogeneity, the capacity to coat complexly shaped substrates and the potential to coat porous substrates, easy parameter control [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], quick preparation time, basic equipment, and ease of operation [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Understanding the ED process may agree to successfully fabricate highly bioactive coatings for quick bone growth.\u003c/p\u003e\u003cp\u003eThe present work aims to control and improve the structure, bioactivity and adhesion strength of HAp reinforced with PVA and collagen peptide (Collg) to form nanocomposite coatings on Ti orthopedic implants by the application of ED process that mimics the natural bone extracellular matrix. Nano-meter sized HAp and HAp-Collg-PVA nanocomposite coatings are synthesized, characterized and electrochemically coated on the surface of Ti substrates and the coated samples were dried at room temperature. The uniform and un-cracked coatings with the high adhesion strength is formed on the Ti substrate is selected and tested for its biological performance. Understanding the ED process may agree to successfully fabricate bioactive and adhesive coatings for quick bone growth. This study seeks to enhance the interfacial bonding of Ti substrates to support bone tissue integration and long-term implant success in orthopedic applications.\u003c/p\u003e"},{"header":"2 Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Materials\u003c/h2\u003e\u003cp\u003eFor the coating, commercially available pure Ti specimens (Grade T3160) of area 2 \u0026times; 1 cm\u003csup\u003e2\u003c/sup\u003e and 1 mm thickness, purchased from Sigma Aldrich (Germany) were used. PVA (99%, Sigma Aldrich, Germany), and collagen peptide (Mw\u0026thinsp;~\u0026thinsp;300000 g mol-1, Hydrolyzed form of collagen type 1, HIMEDIA, India) were used as the raw materials. For in vitro studies, calcium nitrate tetrahydrate, Ca(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e.4H\u003csub\u003e2\u003c/sub\u003eO (99%, Spectrum, India), ammonium dihydrogen orthophosphate, NH\u003csub\u003e4\u003c/sub\u003eH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e (99%, Rankem, India), sodium hydrogen carbonate (purified), NaHCO\u003csub\u003e3\u003c/sub\u003e (99%, Merk, India), dipotassium hydrogen orthophosphate, K\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e (99.9%, Fisher Scientific, USA), magnesium chloride, MgCl\u003csub\u003e2\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO (99%, Nice, India), calcium chloride dehydrate, CaCl\u003csub\u003e2\u003c/sub\u003e.2H\u003csub\u003e2\u003c/sub\u003eO (99%, Fisher Scientific, USA), sodium sulphate anhydrous A.R., Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e (99%, Merk, India), tris buffer A.R., (CH\u003csub\u003e2\u003c/sub\u003eOH)\u003csub\u003e3\u003c/sub\u003eCNH\u003csub\u003e2\u003c/sub\u003e (99%, Spectrum, India), sodium hydroxide pellets A.R. (99%, SRL, India) were used.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Electrodeposition (ED)\u003c/h2\u003e\u003cp\u003eTi substrates were etched with equal volumes of conc. HNO\u003csub\u003e3\u003c/sub\u003e and 30% H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e for 1hr. After that, the strip was cleaned with distilled water and allowed to dry for 30 minutes (mins) at room temperature. The electrodeposition carried out in a three- electrochemical cell, the etched strip act as working electrode i.e., cathode and the platinum (Pt) mesh act as counter electrode (anode) and a standard calomel electrode act as reference electrode. After pretreatment, the ED was carried out in an electrolytic solution containing Ca(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e and NH\u003csub\u003e4\u003c/sub\u003eH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e. To the electrolyte, 0.02g of Collg and 0.05g of PVA are added. The initial pH of the solution obtained was 3.2 and was adjusted to 5.5 using a pH meter by adding 2M NaOH [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] for the codeposition of PVA and collagen peptide. The deposition was carried out for 1 hour at a temperature of 80\u003csup\u003eo\u003c/sup\u003eC under constant current density 1.5 mA/cm\u003csup\u003e2\u003c/sup\u003e and a potential of 1.5-2V respectively [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. After the ED of the coating, the coated substrates were taken out and dried at room temperature.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Physico-chemical and surface characterization\u003c/h2\u003e\u003cp\u003eX-ray diffraction (XRD, Bruker D8 ADVANCE with DAVINCI design) was performed to determine the phase purity of the synthesized material. The chemical functional groups were characterized by fourier-transform infrared spectroscopy (FTIR, Thermoscientific Nicolet iS50). Scanning electron microscope (SEM, Carl Zeiss EVO 18 Research) coupled with energy dispersive spectroscopy (EDS, Carl Zeiss EVO 18 Research) were carried for the surface microstructural morphology analyses. Atomic force microscopy (AFM), Nanosurf Flex-ANA instrument was determined for the surface roughness morphology of the coatings.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Electrochemical investigation\u003c/h2\u003e\u003cp\u003eThe electrochemical properties of HAp-Collg-PVA nanocomposite coatings on titanium (Ti) substrates were investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in a 0.9% NaCl solution. The experiments were carried out in a standard three-electrode setup, with a saturated calomel electrode (SCE) as the reference electrode, a platinum (Pt) electrode as the counter electrode, and the Ti substrate serving as the working electrode for all measurements. All electrochemical analyses were conducted using a Metrohm Autolab PGSTAT204 workstation.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5 In vitro bioactivity study\u003c/h2\u003e\u003cp\u003eThe in vitro bioactivity of the developed coatings can be studied in Kukubo\u0026rsquo;s simulated body fluid (SBF) at 20 days at 36.5oC and pH 7.4 [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The SBF solution was prepared by dissolving the required amount of reagent-grade chemicals of NaCl, NaHCO\u003csub\u003e3\u003c/sub\u003e, KCl, K\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e4\u003c/sub\u003e. 3H\u003csub\u003e2\u003c/sub\u003eO, MgCl\u003csub\u003e2\u003c/sub\u003e. 6H\u003csub\u003e2\u003c/sub\u003eO, HCl, CaCl\u003csub\u003e2\u003c/sub\u003e, Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e in distilled water and buffered to pH using a solution of tris-hydroxylmethyl aminomethane ((CH\u003csub\u003e2\u003c/sub\u003eOH)\u003csub\u003e32\u003c/sub\u003e) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The surface morphology and elemental composition of the coatings before and after bioactivity study was analyzed microscopically and spectroscopically.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.6 Computational methodology\u003c/h2\u003e\u003cp\u003eThe 3D structures of the protein were downloaded in PDB format from the Protein Data Bank (PDB), and it\u0026rsquo;s PDB ID is 2LLP. The chemical structure of Poly vinyl alcohol (CID:11199) and HAp (CID:14781) ligand were obtained from the PubChem in SDF format. HAp is 2D formate hence, we changed it into 3D form and the structure was optimized using B3LYP DFT method and 6-31G(d,p) basis set. DFT calculation is implemented in Gaussian software 09W [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The downloaded protein is opened in Discovery Studio to remove water molecules, ions, solvents, etc present in the systems. Docking calculation was performed using AutoDock 4.2 [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Pymol was used for the visualization of these structures.\u003c/p\u003e\u003c/div\u003e"},{"header":"3 Result and discussion","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Surface and physio-chemical characterization\u003c/h2\u003e\u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\u003ch2\u003e3.1.1 Porosity\u003c/h2\u003e\u003cp\u003eTo regulate the essential functions of nutrition delivery to cells, metabolic dispersion, local pH stability, and cell signaling, the scaffold must have the right amount of porosity. Smaller holes limit the ability of cells to seed in the center of the scaffold and feed on its inner surfaces, while larger pores impact the scaffolds stability and capacity to offer the seeded cells physical support. Cells can migrate or stick to the surface of materials when pores are large enough[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The porosity of the CaP coating and the CaP-Collg-PVA nanocomposites coatings was above 42% and 66%, respectively, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, suggesting that they were appropriately porous and advantageous for cell adhesion and proliferation. The fact that the number of nanofiber mat layers in the scaffold is connected with the porosity of various surface layers, the CaP-Collg-PVA nanocomposite coating demonstrated higher porosity at 66% than the other two coatings[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Increasing porosity lowers the chance of implant failure, promotes bone and cell formation. It was discovered that the pore sizes of the CaP, and CaP-Collg-PVA, nanocomposite coatings were 80\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7, 86\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8, and 90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 \u0026micro;m, respectively. Small pores and high porosity can promote bone cell differentiation and development, improving implant stability and osseointegration.\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\u003ePorosity and pore size of the CaP coating, and CaP-Collg-PVA nanocomposite coatings on Ti substrates\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS. No.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSamples\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePorosity (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePore size (\u0026micro;m)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCaP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCaP-Collg-PVA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e86\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\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=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e3.1.2 Vickers microhardness test\u003c/h2\u003e\u003cp\u003eFor bio-implants, the hardness test findings are essential because they demonstrate how effectively the implants will support weight when subjected to stress in the human body. CaP, and CaP-Collg-PVA, nanocomposite coating Vickers microhardness results on Ti specimens under varied applied stresses are displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. With an increase in applied stresses, it was discovered that the microhardness values rise. Under all applied loads, the CaP-Collg-PVA nanocomposite coating demonstrated a greater microhardness value than both CaP coating during the testing. These coatings demonstrated stability at 50 gf of applied stress, with microhardness (HV) values of 198.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7 and 287.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 HV for CaP, and CaP-Collg-PVA coatings, respectively. As a result, the surface of CaP-Collg-PVA on Ti substrates would have an ideal concentration of Collg and PVA, strengthening the binding and enhancing the bio-mechanical stability of the CaP.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\u003ch2\u003e3.1.3 Contact Angle Analysis\u003c/h2\u003e\u003cp\u003eWettability plays a key role in a material\u0026rsquo;s biological performance. By measuring their contact angle, the hydrophilicity of the CaP coating, and CaP-Collg-PVA, nanocomposite coating on Ti metal strip is demonstrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. With a contact angle of 84.72o, the Ti substrate is hydrophilic, which enhances the materials biological properties, such as its bone-bonding behavior and bioactivity[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Furthermore, the CaP coating, and CaP-Collg-PVA nanocomposite coating have hydrophilic contact angles of 72.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08o (water); 79.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02o (NaCl), and 56.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10o (water); 62.68\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09o (NaCl). The hydrophilic properties of these materials, particularly CaP-Collg-PVA nanocomposite coatings, are advantageous for their possible use in orthopaedic implants.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\u003ch2\u003e3.1.4 Adhesion strength\u003c/h2\u003e\u003cp\u003eFor a Ti specimen to function correctly under physiological environments, the coatings adhesion strength is crucial. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e displays the CaP, and CaP-Collg-PVA, nanocomposite coatings adhesion strengths to Ti metals. Accordingly, the adhesion strengths of the CaP and CaP-Collg-PVA coated on Ti metal are 12.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8, 29.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9, and 32.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 MPa. The CaP-Collg-PVA nanocomposite coatings enhanced adhesion strength is a result of the PVA coated layers greater chemical affinity for Ti[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. This shows strong adhesion between CaP, Collg, and PVA ensures a stable nanocomposite structure that resists physiological stresses, promotes bone cell attachment and growth, and improving durability in the harsh environment of the human body.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\u003ch2\u003e3.1.5 Scanning electron microscopy (SEM)/ Energy dispersive spectroscopy (EDS)\u003c/h2\u003e\u003cp\u003eSEM micrograph and associated EDS pattern of the HAp and HAp-Collg-PVA nanocomposite coatings electrodeposited on etched Ti substrate, performed in both before and after subsequent soaking in SBF for 20 days are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The broad petal-like crystallites of the HAp coating on Ti are seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a). The SEM and EDS images of the HAp coating on the Ti substrate after 20 days of immersion in the SBF solution are displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b). On the coated surface, the evenly dispersed apatite crystals are readily visible. The presence of HAp component elements including Ca, P, O, and Mg may be identified by EDS analysis, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a) and (b). The electrodeposited HAp-Collg-PVA nanocomposite coatings over the etched Ti substrate, which contains petal-like cyrstallites with apatite crystals produced, are depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(c) [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(d) shows the apatite, which was found to be more compact and denser and evenly distributed over the surface of the HAp-Collg-PVA nanocomposite coating on etched Ti that was submerged in SBF for 20 days. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(c) and (d) reveal the elemental components as Ca, P, O, and Mg correspond to HAp, whereas elemental C and N are caused by PVA or maybe by the amino acid residues in collagen peptide, which are verified by the EDS. The Ca\u003csup\u003e2+\u003c/sup\u003e ion aggregate on the metal surface after 20 days of immersion in SBF, gradually gaining a positive charge. In order to create crystalline calcium phosphate, the positively charged surfaces interact with the negatively charged phosphate ions. Magnesium (Mg) is also formed along with calcium and phosphate ions, which plays a significant role in bone ingrowth since the natural bone contains 60% of the total magnesium. The Ca\u003csup\u003e2+\u003c/sup\u003e and PO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e3\u0026minus;\u003c/sup\u003e ions in the SBF are consumed by the generated apatite nuclei as they develop spontaneously. As Ca\u003csup\u003e2+\u003c/sup\u003e and PO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e3\u0026minus;\u003c/sup\u003e ions formed, the EDS data showed that the HAp-Collg-PVA particles had a Ca/P ratio of 1.65, which is close to real bone and causes osseointegration. When the HAp-Collg-PVA nanocomposite coated Ti substrate is embedded in SBF, it is discovered to be uniformly deposited on the surface, with just a few surface-level pores and no significant apparent fractures. As previously indicated, this conclusion is consistent with the research conducted by Degirmenbasi et al and Rusu et al [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. From data it shows the SEM- EDS images of HAp-Collg-PVA nanocomposite coating on Ti substrate immersed in SBF for 20 days at 36.5oC shows that the HAp particles were uniformly distributed in the PVA matrix with no apparent of agglomeration, which indicates the formation of mechanical and biological performance of reinforced nanocomposite coating [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. This resulted from the presence of PVA and the addition of collagen peptide to the PVA matrix, indicating that PVA is essential for the creation of apatite nuclei during sample incubation in SBF solution. This further supports the ability of nanocomposite coatings to promote bone ingrowth. EDS spectra verify that components including Ca, P, O, and Mg are present in the HAp-Collg-PVA nanocomposite. The composite coatings Ca/P atomic ratio, however, increases after 20 days of immersion, demonstrating that the apatite layer forms on the nanocomposites surface more quickly. According to Kukubo et.al [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], negatively charged ions' surface functional groups affect their electrostatic interactions with SBF ions and cause the production of apatite. By drawing Ca2\u0026thinsp;+\u0026thinsp;ions from SBF solution, the OH group of PVA may create a strong intermolecular hydrogen bond with the OH- and PO43- of HAp-Collg-PVA nanocomposite coatings, starting the nucleation of apatite and resulting in the development of stable bonelike apatite [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. From the observe data the rate of apatite precipitation was more on the surface of HAp-Collg-PVA as compared to HAp nanocomposite coating on Ti substrate possess both favorable mechanical and bioactive properties.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section3\"\u003e\u003ch2\u003e3.1.6 Atomic force microscopy (AFM)\u003c/h2\u003e\u003cp\u003eThe coatings morphology and roughness were assessed using a 1 \u0026micro;m scan size. HAp-Collg-PVA nanocomposite coating on Ti is seen to be agglomerated with non-uniform morphology, with a surface diameter of 40 nm, according to a 3D AFM picture displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a). As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(b), the HAp-Collg-PVA coated substrate exhibited consistent apatite formation with a surface diameter of 60 nm following 20 days of immersion in SBF. HAp-Collg-PVA nanocomposite coating (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a)) has an average roughness (Ra) of 0.758 nm and a root mean square roughness (Rq) of 1.091 nm. Similarly, the HAp-Collg-PVA nanocomposite coating in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(b) shows a rough morphology with a root mean square roughness (Rq) of 28.142 nm and an average roughness (Ra) of 22.219 nm following a 20-day soak in SBF. The presence of PVA and collagen peptide in the HAp matrix may raise electrical signals to form bioactive nanocomposite coating on Ti substrate. Increasing the coated substrates roughness enhances cell adhesion and osseointegration[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The thickness of the nanocomposite coating can be analyzed form the 3D image of AFM and it is confirmed from Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a) and (b) the thickness off the coating formed is approximately 3 \u0026micro;m. The AFM images of HAp-Collg-PVA nanocomposite coating on Ti immersed in SBF for 20 days showed relatively increased surface roughness leads to more uniform coverage compared to the one formed with HAp-Collg-PVA coating on Ti. It has found that, a higher surface roughness increases the adhesion of cells[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. It has been demonstrated that excess HAp particles do not distribute well within the PVA, readily weakening the interaction between HAp and PVA[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Apparently, it was observed that collagen peptide in PVA matrix provides a better cellular response such as adhesion, proliferation and differentiation with favorable surface roughness as well as mechanical strength with characterized physiochemical properties[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Studies have shown that strength-enhanced HAp-Collg-PVA nanocomposite coating may be good substitutes for the Ti substrates.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section3\"\u003e\u003ch2\u003e3.1.7 X-ray diffraction (XRD)\u003c/h2\u003e\u003cp\u003eXRD analysis was used to investigate the crystallinity and phase content of the HAp and HAp-Collg- nanocomposite coating on Ti are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(a) and (b). In Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(a), the prominent peaks of the HAp nanocomposite coating on Ti that resulted at 2θ\u0026thinsp;=\u0026thinsp;20.414o, 25.26o, 31.92o, 33.11o, 40.66o, and 44.59o are features of hydroxyapatite. According to the standard JDPDS card 09-0432 file, the observed diffraction peaks show a highly crystalline form of HAp[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Secondary phases like TCP and TTCP were not found. In Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(b), the characteristic peaks corresponding to 2\u0026thinsp;=\u0026thinsp;20.49o, 22.99o, 28.8o, 32.04o 45.21o, 45.56o, 49.29o revealed the relative strong diffraction peak of HAp-Collg-PVA nanocomposite coating. The peaks appeared at 2\u0026thinsp;=\u0026thinsp;23.90o, 32.04o corresponds to the formation of HAp and the characteristic peaks at 2\u0026thinsp;=\u0026thinsp;20.49o indicates non- crystalline behavior of PVA[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] after reinforced with HAp and Collg. The XRD studies revealed that the major phase of HAp-Collg-PVA nanocomposite coatings, the ceramic and polymer both exhibit crystalline behavior in the composite covering, suggesting a negligible alteration in their crystal structures. Similar to real bone, where HAp is equally distributed in the PVA and collagen peptides, this further supports the idea that HAp is finely and uniformly increased in the matrix[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. A very weak and broad peak indicates the non-crystalline behavior of PVA by the incorporation of HAp is due to poor dispersion of HAp in PVA solution.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section3\"\u003e\u003ch2\u003e3.1.8 Fourier transform infrared (FTIR) spectroscopy\u003c/h2\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a) and (b) depicts the FTIR spectra of HAp and HAp-Collg-PVA nanocomposite coatings on Ti. The phosphate ions are responsible for the absorption bands at 574.01, 656.63, 982.81, 1051.29, and 1116.64 cm-1 seen in the spectra, whereas the carbonate ions of the apatite phase were responsible for the faint peak at 1645.25 cm-1 in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a). The peaks at 3472.57 and 3532.92 cm-1 corresponds to O-H absorption stretching bands of HAp[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e] The FTIR spectra of HAp-Collg-PVA coatings represent peaks at 574.38, 657.03, 982.20, 1051.49, 1116.58 cm-1 establishes the presence of phosphate ion in HAp are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(b). The band located at 869.75 cm-1 is associated with the C\u0026thinsp;=\u0026thinsp;C stretching vibration and the C-H out-of-plane vibration of PVA or collagen peptide. Absorption peak around 2980.58 cm-1 originates from the C-H stretching vibration and C-H-wagging vibration in the alkyl groups on the PVA and the absorption bands at 1395.70 cm-1 illustrates the presence of carbonyl group of HAp. The following peaks in the spectra were identified as characteristic peaks of PVA: a wide (O-H) absorption stretching band at 3471.99, 3533.01 cm-1, which showed the existence of polymeric connection of the free hydroxyl groups and bound O-H vibration. The peaks of FTIR confirm the existence of phosphate ions, stretching and bending modes of the O-H groups in the HAp-Collg-PVA nanocomposite coatings on Ti substrate. The presence of (O-H) stretching band indicating the presence of polymeric association of the free hydroxyl groups and bonded O-H stretching vibration and C-H interaction in the alkyl groups is due to PVA backbone[\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. The presence of the carbonate ion results from the interaction between atmospheric carbon dioxide and the nano-HAP precursor alkaline solution sample, this reaction has been seen in other studies too[\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Electrochemical investigation\u003c/h2\u003e\u003cdiv id=\"Sec20\" class=\"Section3\"\u003e\u003ch2\u003e3.2.1 Electrochemical impedance spectroscopy (EIS)\u003c/h2\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e and \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e display the EIS Nyquist impedance plots and the circuit diagram, respectively, for (a) HAp and (b) HAp-Collg-PVA nanocomposite coating on Ti submerged in 0.9% NaCl solutions. The solution resistance, as determined by the data, is RS, the constant phase elements (CPEs) are Q, the polarization resistance, which indicates the resistance between the Ti substrate and a corrosion product layer is RP1, and the second polarization resistance, which represents the resistance between the corrosion product and solution interface, is RP2[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. It is seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e, that both HAp and HAp-Collg-PVA coated specimen showed only half semicircle and the diameter of the semicircle is wider for HAp-Collg-PVA than HAp. The parameters listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e showed that the values of the resistances, RS, RP1 and RP2 for HAp-Collg-PVA nanocomposite coating recorded higher values compared to the HAp coating on Ti. The EIS measurements thus confirm that HAp-Collg-PVA showed better corrosion resistance and adhesion strength than HAp. The Nyquist curves (combined) obtained plot of the HAp and HAp-Collg-PVA coated specimen showed a bigger diameter for the semicircle than the HAp coated specimen due to the increased surface passivation by PVA. The presence of PVA on the Ti surface thus increase the impedance of Ti through increasing its surface passivation. It is also noted that the diameter of the semicircle increases with inhibitor concentration resulting an increase in corrosion resistance of the material[\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. It is obvious from the results that HAp-Collg-PVA coating inhibits the enhancement of the corrosion protection properties of Ti substrate.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\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\u003eThe electrochemical impedance parameters.\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS. no\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMaterial\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eR\u003csub\u003eS\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eR\u003csub\u003eP1\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eR\u003csub\u003eP2\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHAp coated Ti\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e-14.409\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e29.857\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e6966.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHAp/Collg/PVA coated Ti\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e-21.065\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e34.052\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e9998.7\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=\"Sec21\" class=\"Section3\"\u003e\u003ch2\u003e3.2.2 Cyclic voltammetry (CV)\u003c/h2\u003e\u003cp\u003eHAp coating and HAp-Collg-PVA nanocomposite coating on Ti substrate in 0.9% NaCl solution were measured for current and working electrode potential at a scan rate of 0.01 V s-1 to produce the cyclic voltammograms that are displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e(a) and (b). HAp coating nucleation on the Ti surface is demonstrated by Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e(a), which exhibits a reduction potential peak at -0.6 V with an increasing current density from \u0026minus;\u0026thinsp;5\u0026times;10\u0026thinsp;\u0026minus;\u0026thinsp;4 to 2.7\u0026times;10\u0026thinsp;\u0026minus;\u0026thinsp;3 A. In Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e(b), a reduction potential for HAp-Collg-PVA nanocomposite coating with a current density ranging from \u0026minus;\u0026thinsp;1\u0026times;10\u0026thinsp;\u0026minus;\u0026thinsp;3 to 2.8\u0026times;10\u0026thinsp;\u0026minus;\u0026thinsp;3 A at -0.75 V is displayed. The higher the potential applied, the lower the current density. The reduction peak was found on both the graphs but more reduction peak was prominent on HAp-Collg-PVA coating shows the coating does not undergo or very less delamination compared to the HAp coating results in high corrosion resistance and adhesion strength of the coating. The nature of electrode reactions can often be determined based on the peak current in cyclic voltammetry (CV). In contrast to HAp coating on Ti, the desired potential range of a suitable HAp-Collg-PVA nanocomposite coating on Ti substrate via electrodeposition was created based on these findings, which showed a plateau in current density. The addition of PVA and collagen peptide significantly improved the adhesive strength of the coating and corrosion. The more anodic behaviour of the HAp-Collg-PVA coatings showed the stability of the coating. As more PVA particles are formed on the substrate, the electrodes surface charge exchange rate improves, which explains why the current rises as the voltage does [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Computational Studies\u003c/h2\u003e\u003cp\u003eIn our study, structures such as Collg, HAp, and PVA are used for blind molecular docking to investigate the interactions of a Collg with these compounds. The optimized structures are given in the SI. Blind docking was useful in this research since the specific binding site on the Collg was unknown, which allowed us to perform an unbiased search for potential interaction regions. The structures were taken as input for docking simulations carried out. The binding energies derived from the docking study were \u0026minus;\u0026thinsp;6.08 kcal/mol for the Collg\u0026ndash;HAp complex and \u0026minus;\u0026thinsp;2.09 kcal/mol for the Collg\u0026ndash;PVA complex. The higher negative binding energy with HAp indicates stronger and better interaction relative to polyvinyl alcohol. The non-covalent interactions, like hydrogen bonds and van der Waals contacts, were observed. One can see that residues GLN15 and GLY16 of collagen interact with Ca of HAp with distances of 2.2 \u0026Aring; and 3.3 \u0026Aring;, respectively in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e(a). While residue ALA18 interacts with O of one of the PO4 via hydrogen bonding. The hydrogen and oxygen of the hydroxyl group interact with two GLN15 from two chains of collagen via one hydrogen bond. PVA makes two hydrogen bonds with GLY19 and GLN20 of two different chains of collagen shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e(b). These observations provide evidence for the possibility of HAp being a better binding partner for collagen peptides, and this can be pertinent to biomaterial design and tissue engineering.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4 Conclusions","content":"\u003cp\u003eIn the present work, we have successfully fabricated the electrodeposited HAp-Collg-PVA nanocomposite coating on Ti substrate. The XRD and FTIR analysis confirms that the reinforcement of PVA matrix with collagen peptide and HAp, the crystallinity and the intensity of sharp bands found to be increased. The electrochemical treatment could be an effective method for the stability and corrosion resistance of pure Ti substrate. The SEM analysis reveals the surface morphology of nanocomposite coatings confirms that appropriate distribution of apatite on the surface of Ti substrate. The EDS measurements revealed a higher concentration of protein in the HAp-Collg-PVA nanocomposite coating as compared with the HAp coating on Ti. By SEM, AFM, EIS and CV were possible to study the initial stage of the hydroxyapatite presence because this specific technique allows detecting the electrochemical and deposition processes separately. Molecular docking studies reveal that HAp binds with Collg more effectively than with PVA, which suggests that better binding partner for collagen peptides. The HAp-Collg-PVA nanocomposite coating became biologically active without alkaline treatment and favored apatite growth reveals highly bioactive and adhesive Ti implants. HAp alone mimics the mineral phase of bone, the incorporation of Collg introduces biomimetic cues that promote cell adhesion, while PVA improves mechanical stability and homogeneous dispersion of the nanocomposite. Together, HAp-Collg-PVA nanocomposite coating on Ti implants may be excellent substitutes for the physical-chemical interaction of bone implant, thus results in improved bioactivity, cytocompatibility, and potential for strong bone-implant integration. This study proves a promising approach for creating bifunctional surfaces that support the long-term success of Ti-based orthopedic implants.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflict of Interest\u003c/h2\u003e\u003cp\u003eThe author declares no conflict of interest.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eOrchid iDs\u003c/h2\u003e\u003cp\u003eSuja Mathai \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://orcid.org/0000-0002-0614-2742\u003c/span\u003e\u003cspan address=\"https://orcid.org/0000-0002-0614-2742\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003ePriyanka S Shaji \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://orcid.org/0000-0001-8742-8437\u003c/span\u003e\u003cspan address=\"https://orcid.org/0000-0001-8742-8437\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003eSandhya K S \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://orcid.org/0000-0002-3628-0521\u003c/span\u003e\u003cspan address=\"https://orcid.org/0000-0002-3628-0521\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003cp\u003eLimitha Chandran M C \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://orcid.org/0009-0007-7763-406X\u003c/span\u003e\u003cspan address=\"https://orcid.org/0009-0007-7763-406X\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAuthor Contribution StatementType of contribution ContributorsConcept and design Dr. Suja Mathai, Ms. Priyanka S ShajiData acquisition Ms. Priyanka S ShajiData analysis / interpretation Ms. Priyanka S Shaji, Dr. Sandhya K SDrafting manuscript Ms. Priyanka S ShajiCritical revision of manuscript Dr. Suja MathaiStatistical analysis Ms. Priyanka S Shaji, Dr. Sandhya K SAdmin, technical or material support Dr. Suja Mathai, Priyanka S Shaji, Dr. Sandhya K S, Limitha Chandran M CSupervision Dr. Suja MathaiFinal Approval Dr. Suja Mathai\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eThe Central Laboratory for Instrumentation and Facilitation, Biovent Pvt. Ltd., University Campus, Karyavattom, is acknowledged by the authors for its assistance with the biological, XRD, FTIR, and SEM-EDS investigations. For assistance with the adhesion strength, contact angle measurements, and microhardness test, we are grateful to the CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India. Additionally, the EIS, CV, and AFM investigations of the coated surface were made possible by the assistance of ICAR-Central Institute of Fisheries Technology (CIFT), Kochi.\u003c/p\u003e\u003ch2\u003eData Availability Statement\u003c/h2\u003e\u003cp\u003eAll data that support the findings of this study are included within the article. Computational part is included in supporting information.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eN. Moritz, S. Areva, J. Wolke, T. 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Coatings. \u003cb\u003e11\u003c/b\u003e, 110 (2021). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/coatings11010110\u003c/span\u003e\u003cspan address=\"10.3390/coatings11010110\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Electrodeposition, nanocomposite, coating, polyvinyl alcohol, titanium, osseointegration","lastPublishedDoi":"10.21203/rs.3.rs-7829417/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7829417/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eNano-HAp can more easily cause apatite to precipitate on the surface of Ti when combined with poly vinyl alcohol (PVA) and collagen peptide (Collg) coating. The properties of PVA include good adhesion and strong corrosion resistance. In this study, HAp reinforced with collagen peptide nanopowders and PVA nanocrystals was generated using the electrodeposition technique. The in vitro bioactivity of the HAp-Collg-PVA nanocomposite coatings performed in Kokubo's simulated bodily fluid without being subjected to an alkaline treatment. To assess the coatings bioactivity, adhesion power, and corrosion resistance, they were subjected to a variety of physical and electrochemical characterization techniques under physiological conditions. By using the techniques of fourier-infrared spectroscopy (FT-IR), x-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and atomic force microscopy (AFM), it was determined how PVA with Collg as reinforcement affected the structure of nanocomposite coating with HAp on the surface of Ti. Computational studies suggests that Collg interacts with HAp (-6.08 kcal/mol) better than with polyvinyl alcohol (-2.09 kcal/mol). The nanocomposite coatings porosity, hydrophilicity, mechanical stability and adhesion strength were also investigated. PVA and Collg combined with HAp improved bioactivity, corrosion resistance, and adhesion strength. The biomimetic properties this component in this nanocomposite offers a functional platform for promoting osseointegration and improving implant longevity.\u003c/p\u003e","manuscriptTitle":"Augmenting adhesion strength and biomimetic properties of polymeric nanocomposite coatings on titanium implants","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-19 08:30:33","doi":"10.21203/rs.3.rs-7829417/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3c618729-4ff1-43c9-b4a7-b3801d34f1b9","owner":[],"postedDate":"November 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-28T04:38:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-19 08:30:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7829417","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7829417","identity":"rs-7829417","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}