Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area

Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area | 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 Article Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area Qian Long, Sheng-bin He, Jian Sun, Quan-zhi Chen, Hao-dong Bao, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1866177/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Jan, 2023 Read the published version in Scientific Reports → Version 1 posted 8 You are reading this latest preprint version Abstract Selenium is an essential micronutrient element. For the extremely biotoxic of selenite, Selenium nanoparticles (SeNPs) is gaining increasing interest. In this work, a selenium-enriched strain with highly selenite-resistant (up to 173 mmol/L) was isolated from the local specialty food of longevity area and identified as Paenibacillus motobuensis ( P. motobuensis ) LY5201. Most of the SeNPs is accumulated extracellular. SeNPs were around spherical with a diameter of approximately 100 nm. The X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy showed that the purified SeNPs consisted of selenium and proteins. Our results suggested that P. motobuensis LY5201could be a suitable and robust biocatalyst for SeNPs synthesis. In addition, the cytotoxicity effect and the anti-invasive activity of SeNPs on the HepG2 showed an inhibitory effect on HepG2, indicating that SeNPs could be used as a potential anticancer drug. Se nanoparticles Paenibacillus motobuensis Green synthesis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Selenium (Se) is an essential trace element, which forms at least 25 selenoproteins. These proteins involve in antioxidant, catalytic, anti-inflammatory, immunity and antitumor functions [1]. Se may promote longevity through diet [2]. Moreover, longevity area and selenium rich area showed significant positive correlation [3]. However, excessive intake of selenium can cause adverse effects [4]. Selenium nanoparticles (SeNPs) could overcome the high dosages of Se metal and keep the biological activities such as the anticancer [5] and antibacterial properties [6], making SeNPs particularly useful for pharmaceutical and biomedical applications. Selenium nanoparticles (SeNPs) have gained attention in the electronics and optics industries for their special physical characteristics, such as photoelectric, X-ray sensing properties, and catalytic properties [7]. Physico-chemical methods for nanoparticle synthesis are costly, cumbersome, and generate hazardous by-products [8], which hindered the wide application of SeNPs. Biological synthesis is considered to be the most ideal approaches for green synthesis. Additionally, they could provide products with unique size and morphology [6]. A number of microbes could biosynthesize SeNPs intracellularly or extracellularly during the reduction of selenium oxyanions to elemental selenium [9,10], providing a simple and environment-friendly method to prepare SeNPs. However, the selenite tolerance of most reported SeNPs producing microbes is relatively low (<100 mmol/L) [11,12], and the time for the reduction of these toxic forms is long, ranging from 24 to 96 h [13]. How to decrease the time of bioprocess is one of the most important issues for the SeNPs biogenesis [11]. Thus, the identification of novel strains with a high selenium tolerance is urgently needed. In this study, a new Se-reducing bacteria isolate (LY5201) showing extreme tolerance to selenite (173 mmol/L, 30 g/L) was isolated from Chinese Sauerkraut, in Bama, “the hometown of longevity” in the world. We found that SeNPs can be synthesized by Paenibacillus. motobuensis （ P.motobuensis ）LY5201 efficiently under sodium selenite (Na 2 SeO 3 ) stress and anaerobic conditions. SeNPs could be detected within 24 h, which is faster than reported microbes. This strain is suitable for SeNPs preparation. The SeNPs characteristics were determined by transmission electron microscopy (TEM) and fourier-transform infrared (FTIR) spectroscopy. Hereafter, the cytotoxicity of SeNPs was investigated. The SeNPs synthesized by P.motobuensis LY5201 may be used as a promising drug for anticancer. 2. Materials And Methods 2.1 Selenite-reducing strain isolation and identification Samples were isolated from Chinese Sauerkraut (Bama, Guangxi, China). The supernatant of the Chinese Sauerkraut was plated on Luria Bertani (LB) agar containing 500 mg/L sodium selenite. After incubated at 37°C for 24 h, individual colonies are red, indicating Se reduction and Se 0 formation. The single colony was confirmed by 16S rRNA gene sequencing analysis [14]. Isolate 201 (named LY5201) was selected for further study for its rapid growth rate and Se reduction performance. The 16S rRNA gene was amplified and sequenced as previously study [15]. The 16S rRNA gene sequence was compared to previously published sequences present on the EzBioCloud server [16]. A phylogenetic tree was constructed using the maximum likelihood algorithms of MEGA 7[17]. 2.2 Assessment of sensitivity of LY5201 to Na2SeO3 The influence of SeNPs on the proliferation ability of LY5201 was investigated. First, a fresh overnight cell culture without Na 2 SeO 3 was used as seed. Different concentrations of Na 2 SeO 3 (0, 0.5 g/L, 1.0 g/L, 2.0 g/L, 5.0 g/L, 10.0 g/L and 30.0 g/L) were prepared in LB media. The seed was added into these LB media at an initial cell density of 0.3 (OD 600 ). All cultures were incubated at 37°C with rotary shaking at 200 rpm for 24 h. The experiment was done in triplicates for verifying the obtained results. 2.3 Characterizations of SeNPs In order to obtain SeNPs, the sterilized sodium selenite solution was added to the fermentation medium, bringing the final concentration of the solution to 5.0 g/L. The fermentation broth was centrifuged at 15,000×g for 10 min. The resultant pellet was washed three times and resuspended in 20 mL deionized water. To separate the SeNPs from the cell fragments, 5 mL of 1-octanol was added. The mixture was mixed thoroughly and centrifuged at 2,000×g for 5 min. Then, the mixture was placed at 4°C for 24 h. The lower layer containing SeNPs was collected and cleaned consecutively with 70% ethanol, chloroform and deionized sterile water and freeze-dried [18]. To further characterize the SeNPs, transmission electron microscopy (TEM, JEOL-7100), X-ray photoelectron spectroscopy (XPS, Escalab 250Xi), fourier transform infrared spectroscopy (FTIR, 640-IR), dynamic light scattering (DLS, Litesizer 500) and UV-visible analysis (UV-Vis, Varian Cary 100) were carried out as previously described [10]. 2.4 Cytotoxicity Analysis of SeNPs in vitro Cell Counting Kit-8 (CCK-8, Beyotime Biotechnology, Shanghai, China) was used for in vitro cytotoxicity testing of SeNPs. Hepatocarcinoma (HepG2) cells were cultured in DMEM supplemented with 10% fetal bovine serum in 96-well plates. In this experiment, 96 well plates (200 µL media per well) were seeded with cells at final concentration of 1×10 5 cells/mL and incubated in 5% CO 2 incubator at 37°C. After 24 h incubation, SeNPs were added into the culture to keep the final concentrations at 5, 10, 15 and 20 µg/mL The culture was wells incubated in 5% CO 2 incubator at 37°C for 24 h. Then, each well was treated with 10 µL of CCK-8 and incubated at the same previous condition for 2 h. The color intensity of the solution was measured at 450 nm using a multimode microplate reader (SuPerMax 3000FL, China). The percentage of cell viability was measured according to the following equation: Cell viability=(A t /A c ) ×100 Where A t represents the mean absorbance of cells treated with SeNPs, and A c represents the mean absorbance of cells without SeNPs. Data are mean of triplicate experiments. 2.5 Wound Healing Assay The scratch wound assay was used to measure the effect of SeNPs on the migration ability of HepG2[18, 19]. Cells were cultured in 6-well plates. After 24 h, the cell monolayer was scratched with a 10 µL pipette tip to create a gap. After washing three times with serum-free medium, the gap was photographed to determine the wound baseline. Cells were incubated in FBS-free media with SeNPs solution at different concentrations. The wound gap size were evaluated at 24 h post-wounding. Image J was used for wound healing assay. The healing ratee was calculated according to the formula as following[18]: Healing ratio(%)=(A 0 -A f )/A 0 ×100%, Where A 0 represents the area of initial wound area, A f represents the remaining area of wound at 24 h. 3 Results And Discussion 3.1 Isolation and Identification of LY5201 Bama is “the hometown of longevity” in the world. Diet with adequate nutrition is one of the most important factors to longevity [20]. Trace elements play an important role in maintaining metabolic homeostasis in the elderly [21]. Since selenium rich area are related with longevity area, we tried to isolate the selenium-enriched strain from the local specialty food (Sauerkraut). In this study, LY5201 was isolated using LB plate supplemented with 5 mmol/L sodium selenite and exhibited the ability to reduce selenite to red Se 0 (Fig. 1a). As shown in Fig. 1b, 16S rRNA gene sequence and phylogenetic evolution analysis showed that LY5201 have a high degree of similarity (92%) with Paenibacillus motobuensis NR 043153.1. It also exhibited the typical biochemical characteristics of P. motobuensis [22] as indicated in Table S1 (supporting data). The strain LY5201 was identified as P. motobuensis LY5210. It is Gram-negative, rod-shaped bacterium. In addition, this is the first study to prove that a P. motobuensis strain could reduce selenite to Se 0 and biosynthesize SeNPs. 3.2 The Selenite tolerance of LY5201 As shown in Fig. 2, to determine the selenite tolerance of LY5201, bacterial cells were grown in LB media with different concentrations of selenite, and the specific growth rates of cells were 2.81 ± 0.13 h − 1 , 1.46 ± 0.11 h − 1 , 1.74 ± 0.07 h − 1 , 1.67 ± 0.15 h − 1 , 1.09 ± 0.02 h − 1 , 0.19 ± 0.06 h − 1 , 0.11 ± 0.03 h − 1 and 0.07 ± 0.02 h − 1 in selenite concentrations of 0, 0.5 g/L, 1.0 g/L, 2.0 g/L, 5.0 g/L, 10.0 g/L, 20 g/L and 30 g/L, respectively. The absorbance of the cell culture with selenite exceeded the value of control (0 g/L), because of the elemental selenium scatters and absorbs radiation at 600 nm, which contributed to the increased absorbance [23]. LY5201 had an extremely high tolerance to selenite, it could grow in the presence of selenite concentration up to 30 g/L (173 mmol/L). The results indicates that LY5201 has a higher level of selenite resistance than some other bacteria such as Azoarcus sp . CIB (8 mmol/L) [24] and Rhodopseudomonas palustris (8 mmol/L) [25], and it is similar to the selenite-tolerant strain, such as Alcaligenes faecalis (20.7 g/L) [10]. 3.3 Characterizations of P. motobuensis LY5201 and SeNPs The purified SeNPs were characterized. TEM was used to determine the location of SeNPs produced by P. motobuensis LY5201(Fig. 3a). The naoparticles were located in the extracellular spaces. The particles were spherical and had homogenous size distribution. The average size of SeNPs was about 100 nm, similar to those found in Providencia rettgeri [13] and Lactobacillus casei [18]. More researches are needed to elucidate whether vesicular secretion is involved in the formation of SeNPs. The XPS spectra showed that signals of C, O, N, S, P and Se were detected (Fig. 3b). The average particle size of SeNPs was obtained from the DLS analysis (Fig. 4a). The main average size of the SeNPs was found at 130.4 ± 12.34 nm, which is larger than that in TEM analysis. It is possible that the size obtained from DLS does not only depend on the metallic core of SeNPs but also affected by the substances located on the surfaces such as bio-moieties and proteins [4]. The average size of SeNPs indicating that it can be used for biomedical applications such as biomaterial and bioactive drug deliver. As shown in Fig. 4b, SeNPs showed a negative zeta potential (-21.6 mv), indicating their stability in water. The presence of negatively charged functional groups on the surface of SeNPs were responsible for negative values of zeta potentials [26, 27]. As shown in Fig. 4c, the absorption spectra of SeNPs was shown in Fig. 4c. SeNPs exhibit a broad absorption peak at approximately 260 nm corresponds to previous study [7], which confirms the formation of SeNPs. The UV spectra centered between 200 and 300 nm was due to the formation and surface plasmon vibration of SeNPs [28]. As shown in Fig. 4d, the FTIR spectra of the SeNPs showed absorption peaks at 3218 cm -1 , 1571 cm -1 , 1385 cm -1 , 1313 cm -1 , 1063 cm -1 , 770 cm -1 and 559 cm -1 . The peak at 3218 cm -1 corresponds to the O–H stretching, or to the N–H asymmetric stretch of proteins [4, 26]. The peak at 1571 cm -1 corresponds to the amide II band of proteins [29]. Band at 1385 cm -1 , 1313 cm -1 and 1063 cm -1 are assigned to C-N bond of aromatic and aliphatic amines [4]. Peaks at 770 cm -1 and 559 cm -1 may refer to the binding of SeNPs with -OH as Se-O, which indicating the SeNPs is modified by other chemicals. 3.4 The effects of SeNPs on HepG2 The cytotoxicity of SeNPs was evaluated in vitro against the HepG2 cell line at four doses: 0, 5, 10, 15 and 20 µg/mL. The results showed that the viability of HepG2 cells was dose-dependently reduced from 83.9 ± 1.6–66.4%±3.7% (Fig. 5a). The scratch wound assay was carried out to evaluate the effect of SeNPs on the migration of HepG2 (Fig. 5b). Cell migration was examined via wound healing assay. SeNPs at different concentrations showed inhibitory effect on the migration of HepG2. The percentage of open wound was 31.52%, 21.71% and 1.86% in cells treated with SeNPs at 0, 10 and 20 µg/mL in a dose-dependent manner. SeNPs had been reported to have an anticancer activity towards kidney, lung, liver and breast [9]. However, the mechanisms of anticancer are not fully understood, which depending on the methods of synthesis, the functional groups on the surface, the size, and the structure of SeNPs [5, 15, 18, 30]. The antitumor activity of SeNPs synthesized by P.motobuensis LY5201 should be further investigated in the future. 4. Conclusion The selection of the best biocatalysts to synthesize SeNPs in a fast and efficient manner is the most important factor in the SeNPs application. P.motobuensis LY5201 have the ability to synthesize extracellular SeNPs when growing with sodium selenite within 24 h. Organic-aqueous extraction is a successful method for collection of SeNPs. By using this method, biomolecules modified-SeNPs was obtained. The SeNPs had cytotoxicity to HepG2 and inhibited the migration of HepG2. These results indicating that the SeNPs synthesized by P.motobuensis LY5201 may be used as a promising drug or biomaterial for hepatocellular carcinoma. Considering the high selenite resistance, P.motobuensis LY5201 could be used as a selenite bioconversion platform suitable for biological applications. Declarations Fundings ： This work was financially supported by the Natural Science Foundation of Guangxi (2021GXNSFBA196073), Guangxi University middle-aged and young teachers' basic scientific research ability improvement project (2020KY03010), Scientific research and technology development program (201910027), Open Research Fund from Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University (202001), Youth Science Foundation of Guangxi Medical University (GXMUYSF201824). Competing Interests: The authors have no relevant financial or non-financial interests to disclose. Author Contributions: All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Qian Long, Sheng-bin He, Jian Sun, Quan-zhi Chen, Hao-dong Bao, Teng-yue Liang, Bao-yue Liang and Lan-yu Cui. The first draft of the manuscript was written by Lan-yu Cui , Qian Long and Sheng-bin He, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Data Availability: The datasets generated during and/or analyzed during the current study are not publicly available as the data also forms part of an ongoing study, but are available from the corresponding author on reasonable request. Ethics approval: This is an observational study. The “Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area” Research Ethics Committee has confirmed that no ethical approval is required.” References Rayman MP (2000) The importance of selenium to human health. 356:233–241 Zhang L, Zeng H, Cheng WH (2018) Beneficial and paradoxical roles of selenium at nutritional levels of intake in healthspan and longevity. 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Supplementary Files supplymaterials.doc Cite Share Download PDF Status: Published Journal Publication published 02 Jan, 2023 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Major revision 07 Nov, 2022 Reviews received at journal 03 Oct, 2022 Reviewers agreed at journal 30 Sep, 2022 Reviewers invited by journal 29 Sep, 2022 Editor assigned by journal 29 Sep, 2022 Editor invited by journal 03 Aug, 2022 Submission checks completed at journal 03 Aug, 2022 First submitted to journal 17 Jul, 2022 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1866177","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":126141303,"identity":"1811278c-b851-4747-a1d5-e779159b05b1","order_by":0,"name":"Qian Long","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Qian","middleName":"","lastName":"Long","suffix":""},{"id":126141313,"identity":"faf85493-96fe-42c6-8220-c2540bedac42","order_by":1,"name":"Sheng-bin He","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sheng-bin","middleName":"","lastName":"He","suffix":""},{"id":126141315,"identity":"067fae8a-3e8d-4ef6-a0bd-9a43cb7b4c20","order_by":2,"name":"Jian Sun","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jian","middleName":"","lastName":"Sun","suffix":""},{"id":126141316,"identity":"8ff7e295-c680-49d4-b054-6a978f64a66b","order_by":3,"name":"Quan-zhi Chen","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Quan-zhi","middleName":"","lastName":"Chen","suffix":""},{"id":126141318,"identity":"7940f48d-0de9-4ed0-bf5c-8b4d982fe007","order_by":4,"name":"Hao-dong Bao","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hao-dong","middleName":"","lastName":"Bao","suffix":""},{"id":126141320,"identity":"3c406e6b-73e4-4b54-8b8d-6c94d9abf334","order_by":5,"name":"Teng-yue Liang","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Teng-yue","middleName":"","lastName":"Liang","suffix":""},{"id":126141322,"identity":"37aa92f4-170f-413b-9cb7-ea8eb5c61606","order_by":6,"name":"Bao-yue Liang","email":"","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Bao-yue","middleName":"","lastName":"Liang","suffix":""},{"id":126141324,"identity":"48a081a0-25bb-49b3-b964-a43ebf66868d","order_by":7,"name":"Lan-yu Cui","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+klEQVRIiWNgGAWjYFACxsYDDAY2ckBGAwgRpaXhAENBmjEPCVoYGA4wfDic2APRToRy/hnJDYd5DJjT9/Mfbnv4dcdheQb23scvGGru4NQicSMRpIUtt0cisd1Y9sxhwwae42YWDMee4dRiIAHWwgPUwtgmLdl2mLFBIo3NgLHhMCEtEuk8/AfBWuyJ1WKQwMOQ2Cb5se1wIlAL8wN8WiTOPGw4OMcgwbDnRmKbNGNbenIbzzE2hoRjuLXwt6c/fPDmz3959v7jzyR/tlnb9rO3MX/4UINbCwgw8UAZzCAGGxBJJODVAIzAH2gM5g8EdIyCUTAKRsHIAgCBM1dELlrPWgAAAABJRU5ErkJggg==","orcid":"","institution":"Guangxi Medical University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Lan-yu","middleName":"","lastName":"Cui","suffix":""}],"badges":[],"createdAt":"2022-07-17 07:59:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1866177/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1866177/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-022-26396-4","type":"published","date":"2023-01-02T18:14:11+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":24942921,"identity":"45a991a4-6136-4a91-8950-122545804344","added_by":"auto","created_at":"2022-08-08 20:12:31","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":61223,"visible":true,"origin":"","legend":"\u003cp\u003eGrowth of strain LY5201 on LB agar plates and phylogenetic analysis of the strain LY5201. (a) Images of cultures of strain LY5201 grown in absence (left) and presence (right) of 5 mmol/L Na\u003csub\u003e2\u003c/sub\u003eSeO\u003csub\u003e3\u003c/sub\u003e. The red colony color indicates selenite reduction and the formation of elemental selenium (Se\u003csup\u003e0\u003c/sup\u003e). (b) Maximum likelihood tree based on the 16S rRNA gene sequence of isolate LY5201. The scale bars indicate 0.05 substitutions per site.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig.1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/a4fb82900d1abb1d5180ac22.jpg"},{"id":24943364,"identity":"3dd8b1dd-39cc-4b0d-adbf-176d97359d9b","added_by":"auto","created_at":"2022-08-08 20:17:31","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":60196,"visible":true,"origin":"","legend":"\u003cp\u003eGrowth of \u003cem\u003eP. motobuensis\u003c/em\u003e LY5201 in different concentrations of Na\u003csub\u003e2\u003c/sub\u003eSeO\u003csub\u003e3\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"Fig.2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/19814127e65ff3cf935158ab.jpg"},{"id":24943363,"identity":"89771d78-f634-40dd-90e9-2dd2cf8d5553","added_by":"auto","created_at":"2022-08-08 20:17:31","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":73074,"visible":true,"origin":"","legend":"\u003cp\u003eCharacterizations of \u003cem\u003eP.motobuensis \u003c/em\u003eLY5201 and SeNPs (a) TEM micrographs showing SeNPs produced by\u003cem\u003e P.motobuensis\u003c/em\u003e LY5201 at 24 h. (b) Extracted biomolecules capped-SeNPs contained C, N, O, Se, S and P elements by X-ray photoelectron Spectroscopy (XPS) analysis.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig.3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/16470673f7c95023849abc1a.jpg"},{"id":24942919,"identity":"d71cb825-103e-460e-af0f-6b490d2966db","added_by":"auto","created_at":"2022-08-08 20:12:31","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":84452,"visible":true,"origin":"","legend":"\u003cp\u003eCharacterizations of SeNP\u003csub\u003eS\u003c/sub\u003e. (a) zeta potentials of SeNPs. (b) Size distribution of SeNPs. (c) UV-visible spectra of SeNPs in distilled water. (d) FTIR spectra of SeNPs.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig.4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/cb5c9e3a11157724041fcfe2.jpg"},{"id":24942920,"identity":"bceb7d5e-7de8-4917-991b-13231c6e54f6","added_by":"auto","created_at":"2022-08-08 20:12:31","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":55567,"visible":true,"origin":"","legend":"\u003cp\u003eThe effects of SeNPs on HepG2. (a)The cytotoxicity of SeNPs on HepG2 was determined by CCK-8 assay. (b) Cell migration was examined by wound healing assays.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig.5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/d5ba6f9a26d6a61167e17da2.jpg"},{"id":44716258,"identity":"a7819ad1-ea6d-42a6-ad97-720bcdf379e5","added_by":"auto","created_at":"2023-10-16 18:25:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":654178,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/97248232-8037-4491-8dc5-96ff508ea050.pdf"},{"id":24942916,"identity":"82e0b852-da6e-4000-a6e2-ba08b7e3a745","added_by":"auto","created_at":"2022-08-08 20:12:31","extension":"doc","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":32768,"visible":true,"origin":"","legend":"","description":"","filename":"supplymaterials.doc","url":"https://assets-eu.researchsquare.com/files/rs-1866177/v1/8cb2faaceeccfe44c992436e.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSelenium (Se) is an essential trace element, which forms at least 25 selenoproteins. These proteins involve in antioxidant, catalytic, anti-inflammatory, immunity and antitumor functions [1]. Se may promote longevity through diet [2]. Moreover, longevity area and selenium rich area showed significant positive correlation [3]. However, excessive intake of selenium can cause adverse effects [4]. Selenium nanoparticles (SeNPs) could overcome the high dosages of Se metal and keep the biological activities such as the anticancer [5] and antibacterial properties [6], making SeNPs particularly useful for pharmaceutical and biomedical applications.\u003c/p\u003e\n\u003cp\u003eSelenium nanoparticles (SeNPs) have gained attention in the electronics and optics industries for their special physical characteristics, such as photoelectric, X-ray sensing properties, and catalytic properties [7]. Physico-chemical methods for nanoparticle synthesis are costly, cumbersome, and generate hazardous by-products [8], which hindered the wide application of SeNPs. Biological synthesis is considered to be the most ideal approaches for green synthesis. Additionally, they could provide products with unique size and morphology [6]. A number of microbes could biosynthesize SeNPs intracellularly or extracellularly during the reduction of selenium oxyanions to elemental selenium [9,10], providing a simple and environment-friendly method to prepare SeNPs. However, the selenite tolerance of most reported SeNPs producing microbes is relatively low (\u0026lt;100 mmol/L) [11,12], and the time for the reduction of these toxic forms is long, ranging from 24 to 96 h [13]. How to decrease the time of bioprocess is one of the most important issues for the SeNPs biogenesis [11]. Thus, the identification of novel strains with a high selenium tolerance is urgently needed.\u003c/p\u003e\n\u003cp\u003eIn this study, a new Se-reducing bacteria isolate (LY5201) showing extreme tolerance to selenite (173 mmol/L, 30 g/L) was isolated from Chinese Sauerkraut, in Bama, \u0026ldquo;the hometown of longevity\u0026rdquo; in the world. We found that SeNPs can be synthesized by \u003cem\u003ePaenibacillus. motobuensis\u003c/em\u003e （\u003cem\u003eP.motobuensis\u003c/em\u003e）LY5201 efficiently under sodium selenite (Na\u003csub\u003e2\u003c/sub\u003eSeO\u003csub\u003e3\u003c/sub\u003e) stress and anaerobic\u0026nbsp;conditions. SeNPs could be detected within 24 h, which is faster than reported microbes. This strain is suitable for SeNPs preparation. The SeNPs characteristics were determined by transmission electron microscopy (TEM) and\u0026nbsp;fourier-transform infrared (FTIR) spectroscopy. Hereafter, the cytotoxicity of SeNPs was investigated. The SeNPs synthesized by \u003cem\u003eP.motobuensis\u003c/em\u003e LY5201 may be used as a promising drug for anticancer.\u003c/p\u003e"},{"header":"2. Materials And Methods","content":"\u003cdiv\u003e\n \u003ch2\u003e2.1 Selenite-reducing strain isolation and identification\u003c/h2\u003e\n \u003cp\u003eSamples were isolated from Chinese Sauerkraut (Bama, Guangxi, China). The supernatant of the Chinese Sauerkraut was plated on Luria Bertani (LB) agar containing 500 mg/L sodium selenite. After incubated at 37\u0026deg;C for 24 h, individual colonies are red, indicating Se reduction and Se\u003csup\u003e0\u003c/sup\u003e formation. The single colony was confirmed by 16S rRNA gene sequencing analysis [14]. Isolate 201 (named LY5201) was selected for further study for its rapid growth rate and Se reduction performance. The 16S rRNA gene was amplified and sequenced as previously study [15]. The 16S rRNA gene sequence was compared to previously published sequences present on the EzBioCloud server [16]. A phylogenetic tree was constructed using the maximum likelihood algorithms of MEGA 7[17].\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003ch2\u003e2.2 Assessment of sensitivity of LY5201 to Na2SeO3\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe influence of SeNPs on the proliferation ability of LY5201 was investigated. First, a fresh overnight cell culture without Na\u003csub\u003e2\u003c/sub\u003eSeO\u003csub\u003e3\u003c/sub\u003e was used as seed. Different concentrations of Na\u003csub\u003e2\u003c/sub\u003eSeO\u003csub\u003e3\u003c/sub\u003e (0, 0.5 g/L, 1.0 g/L, 2.0 g/L, 5.0 g/L, 10.0 g/L and 30.0 g/L) were prepared in LB media. The seed was added into these LB media at an initial cell density of 0.3 (OD\u003csub\u003e600\u003c/sub\u003e). All cultures were incubated at 37\u0026deg;C with rotary shaking at 200 rpm for 24 h. The experiment was done in triplicates for verifying the obtained results.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003ch2\u003e2.3 Characterizations of SeNPs\u003c/h2\u003e\n \u003cp\u003eIn order to obtain SeNPs, the sterilized sodium selenite solution was added to the fermentation medium, bringing the final concentration of the solution to 5.0 g/L. The fermentation broth was centrifuged at 15,000\u0026times;g for 10 min. The resultant pellet was washed three times and resuspended in 20 mL deionized water. To separate the SeNPs from the cell fragments, 5 mL of 1-octanol was added. The mixture was mixed thoroughly and centrifuged at 2,000\u0026times;g for 5 min. Then, the mixture was placed at 4\u0026deg;C for 24 h. The lower layer containing SeNPs was collected and cleaned consecutively with 70% ethanol, chloroform and deionized sterile water and freeze-dried [18].\u003c/p\u003e\n \u003cp\u003eTo further characterize the SeNPs, transmission electron microscopy (TEM, JEOL-7100), X-ray photoelectron spectroscopy (XPS, Escalab 250Xi), fourier transform infrared spectroscopy (FTIR, 640-IR), dynamic light scattering (DLS, Litesizer 500) and UV-visible analysis (UV-Vis, Varian Cary 100) were carried out as previously described [10].\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003ch2\u003e2.4 Cytotoxicity Analysis of SeNPs in vitro\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eCell Counting Kit-8 (CCK-8, Beyotime Biotechnology, Shanghai, China) was used for in vitro cytotoxicity testing of SeNPs. Hepatocarcinoma (HepG2) cells were cultured in DMEM supplemented with 10% fetal bovine serum in 96-well plates. In this experiment, 96 well plates (200 \u0026micro;L media per well) were seeded with cells at final concentration of 1\u0026times;10\u003csup\u003e5\u003c/sup\u003e cells/mL and incubated in 5% CO\u003csub\u003e2\u003c/sub\u003e incubator at 37\u0026deg;C. After 24 h incubation, SeNPs were added into the culture to keep the final concentrations at 5, 10, 15 and 20 \u0026micro;g/mL The culture was wells incubated in 5% CO\u003csub\u003e2\u003c/sub\u003e incubator at 37\u0026deg;C for 24 h. Then, each well was treated with 10 \u0026micro;L of CCK-8 and incubated at the same previous condition for 2 h. The color intensity of the solution was measured at 450 nm using a multimode microplate reader (SuPerMax 3000FL, China). The percentage of cell viability was measured according to the following equation:\u003c/p\u003e\n \u003cp\u003eCell viability=(A\u003csub\u003et\u003c/sub\u003e/A\u003csub\u003ec\u003c/sub\u003e) \u0026times;100\u003c/p\u003e\n \u003cp\u003eWhere A\u003csub\u003et\u003c/sub\u003e represents the mean absorbance of cells treated with SeNPs, and A\u003csub\u003ec\u003c/sub\u003e represents the mean absorbance of cells without SeNPs. Data are mean of triplicate experiments.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003ch2\u003e2.5 Wound Healing Assay\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe scratch wound assay was used to measure the effect of SeNPs on the migration ability of HepG2[18, 19]. Cells were cultured in 6-well plates. After 24 h, the cell monolayer was scratched with a 10 \u0026micro;L pipette tip to create a gap. After washing three times with serum-free medium, the gap was photographed to determine the wound baseline. Cells were incubated in FBS-free media with SeNPs solution at different concentrations. The wound gap size were evaluated at 24 h post-wounding. Image J was used for wound healing assay. The healing ratee was calculated according to the formula as following[18]:\u003c/p\u003e\n \u003cp\u003eHealing ratio(%)=(A\u003csub\u003e0\u003c/sub\u003e-A\u003csub\u003ef\u003c/sub\u003e)/A\u003csub\u003e0\u003c/sub\u003e \u0026times;100%,\u003c/p\u003e\n \u003cp\u003eWhere A\u003csub\u003e0\u003c/sub\u003e represents the area of initial wound area, A\u003csub\u003ef\u003c/sub\u003e represents the remaining area of wound at 24 h.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"3 Results And Discussion","content":"\u003cdiv\u003e\n \u003cdiv\u003e\u003cstrong\u003e3.1 Isolation and Identification of LY5201\u003c/strong\u003e\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003cdiv\u003e\n \u003cp\u003eBama is \u0026ldquo;the hometown of longevity\u0026rdquo; in the world. Diet with adequate nutrition is one of the most important factors to longevity [20]. Trace elements play an important role in maintaining metabolic homeostasis in the elderly [21]. Since selenium rich area are related with longevity area, we tried to isolate the selenium-enriched strain from the local specialty food (Sauerkraut). In this study, LY5201 was isolated using LB plate supplemented with 5 mmol/L sodium selenite and exhibited the ability to reduce selenite to red Se\u003csup\u003e0\u003c/sup\u003e (Fig.\u0026nbsp;1a).\u003c/p\u003e\n \u003c/div\u003e\n \u003cp\u003eAs shown in Fig. 1b, 16S rRNA gene sequence and phylogenetic evolution analysis showed that LY5201 have a high degree of similarity (92%) with \u003cem\u003ePaenibacillus motobuensis\u003c/em\u003e NR 043153.1. It also exhibited the typical biochemical characteristics of \u003cem\u003eP. motobuensis\u003c/em\u003e [22] as indicated in Table S1 (supporting data). The strain LY5201 was identified as \u003cem\u003eP. motobuensis\u003c/em\u003e LY5210. It is Gram-negative, rod-shaped bacterium. In addition, this is the first study to prove that a \u003cem\u003eP. motobuensis\u003c/em\u003e strain could reduce selenite to Se\u003csup\u003e0\u003c/sup\u003e and biosynthesize SeNPs.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003cp\u003e\u003cstrong\u003e3.2 The Selenite tolerance of LY5201\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eAs shown in Fig.\u0026nbsp;2, to determine the selenite tolerance of LY5201, bacterial cells were grown in LB media with different concentrations of selenite, and the specific growth rates of cells were 2.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 1.46\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 1.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 1.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 1.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 0.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 0.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in selenite concentrations of 0, 0.5 g/L, 1.0 g/L, 2.0 g/L, 5.0 g/L, 10.0 g/L, 20 g/L and 30 g/L, respectively. The absorbance of the cell culture with selenite exceeded the value of control (0 g/L), because of the elemental selenium scatters and absorbs radiation at 600 nm, which contributed to the increased absorbance [23]. LY5201 had an extremely high tolerance to selenite, it could grow in the presence of selenite concentration up to 30 g/L (173 mmol/L). The results indicates that LY5201 has a higher level of selenite resistance than some other bacteria such as \u003cem\u003eAzoarcus sp\u003c/em\u003e. CIB (8 mmol/L) [24] and \u003cem\u003eRhodopseudomonas palustris\u003c/em\u003e (8 mmol/L) [25], and it is similar to the selenite-tolerant strain, such as \u003cem\u003eAlcaligenes faecalis\u003c/em\u003e (20.7 g/L) [10].\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003cstrong\u003e3.3 Characterizations of P. motobuensis LY5201 and SeNPs\u003c/strong\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe purified SeNPs were characterized. TEM was used to determine the location of SeNPs produced by \u003cem\u003eP. motobuensis\u003c/em\u003e LY5201(Fig.\u0026nbsp;3a). The naoparticles were located in the extracellular spaces. The particles were spherical and had homogenous size distribution. The average size of SeNPs was about 100 nm, similar to those found in \u003cem\u003eProvidencia rettgeri\u003c/em\u003e [13] and \u003cem\u003eLactobacillus casei\u003c/em\u003e [18]. More researches are needed to elucidate whether vesicular secretion is involved in the formation of SeNPs.\u003c/p\u003e\n \u003c/div\u003e\n \u003cp\u003eThe XPS spectra showed that signals of C, O, N, S, P and Se were detected (Fig. 3b). The average particle size of SeNPs was obtained from the DLS analysis (Fig. 4a). The main average size of the SeNPs was found at 130.4\u0026thinsp;\u0026plusmn;\u0026thinsp;12.34 nm, which is larger than that in TEM analysis. It is possible that the size obtained from DLS does not only depend on the metallic core of SeNPs but also affected by the substances located on the surfaces such as bio-moieties and proteins [4]. The average size of SeNPs indicating that it can be used for biomedical applications such as biomaterial and bioactive drug deliver. As shown in Fig. 4b, SeNPs showed a negative zeta potential (-21.6 mv), indicating their stability in water. The presence of negatively charged functional groups on the surface of SeNPs were responsible for negative values of zeta potentials [26, 27].\u003c/p\u003e\n \u003cdiv\u003e\n \u003cp\u003eAs shown in Fig. 4c, the absorption spectra of SeNPs was shown in Fig. 4c. SeNPs exhibit a broad absorption peak at approximately 260 nm corresponds to previous study [7], which confirms the formation of SeNPs. The UV spectra centered between 200 and 300 nm was due to the formation and surface plasmon vibration of SeNPs [28]. As shown in Fig. 4d, the FTIR spectra of the SeNPs showed absorption peaks at 3218 cm\u003csup\u003e-1\u003c/sup\u003e, 1571 cm\u003csup\u003e-1\u003c/sup\u003e, 1385 cm\u003csup\u003e-1\u003c/sup\u003e, 1313 cm\u003csup\u003e-1\u003c/sup\u003e, 1063 cm\u003csup\u003e-1\u003c/sup\u003e, 770 cm\u003csup\u003e-1\u003c/sup\u003e and 559 cm\u003csup\u003e-1\u003c/sup\u003e. The peak at 3218 cm\u003csup\u003e-1\u003c/sup\u003e corresponds to the O\u0026ndash;H stretching, or to the N\u0026ndash;H asymmetric stretch of proteins [4, 26]. The peak at 1571 cm\u003csup\u003e-1\u003c/sup\u003e corresponds to the amide II band of proteins [29]. Band at 1385 cm\u003csup\u003e-1\u003c/sup\u003e, 1313 cm\u003csup\u003e-1\u003c/sup\u003e and 1063 cm\u003csup\u003e-1\u003c/sup\u003e are assigned to C-N bond of aromatic and aliphatic amines [4]. Peaks at 770 cm\u003csup\u003e-1\u003c/sup\u003e and 559 cm\u003csup\u003e-1\u003c/sup\u003e may refer to the binding of SeNPs with -OH as Se-O, which indicating the SeNPs is modified by other chemicals.\u003c/p\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cstrong\u003e3.4 The effects of SeNPs on HepG2\u003c/strong\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n \u003cp\u003eThe cytotoxicity of SeNPs was evaluated in vitro against the HepG2 cell line at four doses: 0, 5, 10, 15 and 20 \u0026micro;g/mL. The results showed that the viability of HepG2 cells was dose-dependently reduced from 83.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u0026ndash;66.4%\u0026plusmn;3.7% (Fig.\u0026nbsp;5a).\u003c/p\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe scratch wound assay was carried out to evaluate the effect of SeNPs on the migration of HepG2 (Fig. 5b). Cell migration was examined via wound healing assay. SeNPs at different concentrations showed inhibitory effect on the migration of HepG2. The percentage of open wound was 31.52%, 21.71% and 1.86% in cells treated with SeNPs at 0, 10 and 20 \u0026micro;g/mL in a dose-dependent manner. SeNPs had been reported to have an anticancer activity towards kidney, lung, liver and breast [9]. However, the mechanisms of anticancer are not fully understood, which depending on the methods of synthesis, the functional groups on the surface, the size, and the structure of SeNPs [5, 15, 18, 30]. The antitumor activity of SeNPs synthesized by \u003cem\u003eP.motobuensis\u003c/em\u003e LY5201 should be further investigated in the future.\u003c/p\u003e\n \u003c/div\u003e\n\n\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThe selection of the best biocatalysts to synthesize SeNPs in a fast and efficient manner is the most important factor in the SeNPs application. \u003cem\u003eP.motobuensis\u003c/em\u003e LY5201 have the ability to synthesize extracellular SeNPs when growing with sodium selenite\u0026nbsp;within\u0026nbsp;24 h. Organic-aqueous extraction is a successful method for collection of SeNPs. By using this method, biomolecules modified-SeNPs was obtained. The SeNPs had cytotoxicity to HepG2 and inhibited the migration of HepG2. These results indicating that the SeNPs synthesized by \u003cem\u003eP.motobuensis\u003c/em\u003e LY5201 may be used as a promising drug or biomaterial for hepatocellular carcinoma. Considering the high selenite resistance, \u003cem\u003eP.motobuensis\u0026nbsp;\u003c/em\u003eLY5201 could be used as a selenite bioconversion platform suitable for biological applications.\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFundings\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003eThis work was financially supported by the Natural Science Foundation of Guangxi (2021GXNSFBA196073), Guangxi University middle-aged and young teachers\u0026apos; basic scientific research ability improvement project (2020KY03010), Scientific research and technology development program (201910027), Open Research Fund from Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University (202001), Youth Science Foundation of Guangxi Medical University (GXMUYSF201824).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u0026nbsp;\u003c/strong\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u0026nbsp;\u003c/strong\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by\u0026nbsp;Qian Long, Sheng-bin He, Jian Sun, Quan-zhi Chen, Hao-dong Bao, Teng-yue Liang, Bao-yue Liang and Lan-yu Cui. The first draft of the manuscript was written by\u0026nbsp;Lan-yu Cui , Qian Long and Sheng-bin He,\u0026nbsp;and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u0026nbsp;\u003c/strong\u003eThe datasets generated during and/or analyzed during the current study are not publicly available\u0026nbsp;as the data also forms part of an ongoing study,\u0026nbsp;but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval:\u0026nbsp;\u003c/strong\u003eThis is an observational study. The \u0026ldquo;Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area\u0026rdquo; Research Ethics Committee has confirmed that no ethical approval is required.\u0026rdquo;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003e\u003cspan\u003eRayman MP (2000) The importance of selenium to human health. 356:233\u0026ndash;241\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003e\u003cspan\u003eZhang L, Zeng H, Cheng WH (2018) Beneficial and paradoxical roles of selenium at nutritional levels of intake in healthspan and longevity. 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J Mater Chem B 4:2351\u0026ndash;2358. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1039/c5tb02710a\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Se nanoparticles, Paenibacillus motobuensis, Green synthesis","lastPublishedDoi":"10.21203/rs.3.rs-1866177/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1866177/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSelenium is an essential micronutrient element. For the extremely biotoxic of selenite, Selenium nanoparticles (SeNPs) is gaining increasing interest. In this work, a selenium-enriched strain with highly selenite-resistant (up to 173 mmol/L) was isolated from the local specialty food of longevity area and identified as \u003cem\u003ePaenibacillus motobuensis \u003c/em\u003e(\u003cem\u003eP. motobuensis\u003c/em\u003e) LY5201. Most of the SeNPs is accumulated extracellular. SeNPs were around spherical with a diameter of approximately 100 nm. The X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy showed that the purified SeNPs consisted of selenium and proteins. Our results suggested that \u003cem\u003eP. motobuensis\u003c/em\u003e LY5201could be a suitable and robust biocatalyst for SeNPs synthesis. In addition, the cytotoxicity effect and the anti-invasive activity of SeNPs on the HepG2 showed an inhibitory effect on HepG2, indicating that SeNPs could be used as a potential anticancer drug.\u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Preparation, characteristics and cytotoxicity of green synthesized selenium nanoparticles using Paenibacillus motobuensis LY5201 isolated from the local specialty food of longevity area","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-08-08 20:12:29","doi":"10.21203/rs.3.rs-1866177/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-11-07T05:52:20+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-10-03T12:33:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"54b79a88-2a82-4180-b2a2-7909c3bb67a4","date":"2022-09-30T15:11:45+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-09-29T14:27:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-09-29T14:20:30+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2022-08-03T12:21:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-08-03T12:08:13+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2022-07-17T07:46:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fc1f9bed-0006-4793-8c76-8e666bcc4d9f","owner":[],"postedDate":"August 8th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T18:20:35+00:00","versionOfRecord":{"articleIdentity":"rs-1866177","link":"https://doi.org/10.1038/s41598-022-26396-4","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2023-01-02 18:14:11","publishedOnDateReadable":"January 2nd, 2023"},"versionCreatedAt":"2022-08-08 20:12:29","video":"","vorDoi":"10.1038/s41598-022-26396-4","vorDoiUrl":"https://doi.org/10.1038/s41598-022-26396-4","workflowStages":[]},"version":"v1","identity":"rs-1866177","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1866177","identity":"rs-1866177","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}