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Zheng M, Ma X, Tan J, Zhao H, Yang Y, Ye X, Liu M, Li H. Enhancement of Biocompatibility of High-Transparency Zirconia Abutments with Human Gingival Fibroblasts via Cold Atmospheric Plasma Treatment: An In Vitro Study. J Funct Biomater 2024; 15:200. [PMID: 39057321 PMCID: PMC11277629 DOI: 10.3390/jfb15070200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 07/10/2024] [Accepted: 07/19/2024] [Indexed: 07/28/2024] Open
Abstract
The objective of this study was to explore the effects of cold atmospheric plasma (CAP) treatment on the biological behavior of human gingival fibroblasts (HGFs) cultured on the surface of high-transparency zirconia. Two types of zirconia, 3Y-ZTP and 4Y-PSZ, were subjected to a CAP treatment for various treatment durations. Analyses of the physical and chemical properties of 3Y-ZTP and 4Y-PSZ were conducted using scanning electron microscopy, contact angle measurements, and X-ray photoelectron spectroscopy, both before and after CAP treatment. The biological responses of HGFs on both surfaces were assessed using CCK-8 assay, confocal laser scanning microscopy, and real-time PCR. Initially, the oxygen and hydroxyl contents on the surface of 4Y-PSZ exceeded those on 3Y-ZTP. CAP treatment enhanced the surface hydrophilicity and the reactive oxygen species (ROS) content of 4Y-PSZ, while not altering the surface morphology. After CAP treatment, HGFs' adhesion on 4Y-PSZ was superior, with more pronounced effects compared to 3Y-ZTP. Notably, HGFs counts and the expression of adhesion-related genes on 4Y-PSZ peaked following the CAP exposures for 30 s and 60 s. Consequently, this study demonstrates that, following identical CAP treatments, 4Y-PSZ is more effective in promoting HGFs adhesion compared to traditional 3Y-ZTP zirconia.
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Affiliation(s)
- Miao Zheng
- Department of Stomatology, Peking University Third Hospital, Beijing 100191, China; (M.Z.); (X.M.)
| | - Xinrong Ma
- Department of Stomatology, Peking University Third Hospital, Beijing 100191, China; (M.Z.); (X.M.)
| | - Jianguo Tan
- Department of Prosthodontics, Peking University School and Hospital of Stomatology and National Center for Stomatology and National Clinical Research Center for Oral Diseases and National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China; (J.T.); (Y.Y.); (X.Y.)
| | - Hengxin Zhao
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China;
| | - Yang Yang
- Department of Prosthodontics, Peking University School and Hospital of Stomatology and National Center for Stomatology and National Clinical Research Center for Oral Diseases and National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China; (J.T.); (Y.Y.); (X.Y.)
| | - Xinyi Ye
- Department of Prosthodontics, Peking University School and Hospital of Stomatology and National Center for Stomatology and National Clinical Research Center for Oral Diseases and National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China; (J.T.); (Y.Y.); (X.Y.)
| | - Mingyue Liu
- First Clinical Division, Peking University School and Hospital of Stomatology, Beijing 100034, China
| | - Heping Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China;
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Jiang Y, Bao X, Yu Y, Zhang Y, Liu M, Meng F, Wang B, Chen J. Effects of different plasma treatments on bonding properties of zirconia. Heliyon 2024; 10:e32493. [PMID: 38975209 PMCID: PMC11225731 DOI: 10.1016/j.heliyon.2024.e32493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 07/09/2024] Open
Abstract
This in vitro study was to evaluate the effect of different non-thermal atmospheric pressure plasma (NTP) on shear bond strength (SBS) between yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and self-adhesive resin cement. In this study, The Y-TZP specimens were divided into 4 groups according to the surface treatment methods as follows: Control (no surface treatment), Sb (Sandblasting), AP(argon NTP), and CP(20 % oxygen and 80 % argon combination NTP). Y-TZP specimens were randomly selected from each group to observe and test the following indexes: scanning electron microscope to observe the surface morphology; atomic force microscope to detect the surface roughness; contact angle detector to detect the surface contact angle; energy spectrometer to analyze the surface elements. Then, resin cement (Rely X-U200) was bonded to human isolated teeth with Y-TZP specimens to measure SBS. The results showed that for the SE test, the NTP group was significantly higher than the control group (p < 0.05). The results of the SBS test showed that the SBS values of the NTP group were significantly higher than those of the other groups, regardless of the plasma treatment (p < 0.05). However, there was no significant difference between groups AP and CP in a test of SBS (p > 0.05). This study shows that non-thermal atmospheric pressure plasma can improve the shear bond strength of Y-TZP by increasing the surface energy. The addition of oxygen ratio to argon is more favorable to increase the shear bond strength and is worth further investigation.
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Affiliation(s)
- Yulin Jiang
- Chongqing University Central Hospital, Chongqing Emergency Medical Center, 400014, Chongqing Province, China
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Xudong Bao
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Yang Yu
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Yannan Zhang
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Min Liu
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Fanhao Meng
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Bo Wang
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
| | - Jianfeng Chen
- Department of Stomatology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning Province, China
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Hu B, Qiao W, Cao Y, Fu X, Song J. A sono-responsive antibacterial nanosystem co-loaded with metformin and bone morphogenetic protein-2 for mitigation of inflammation and bone loss in experimental peri-implantitis. Front Bioeng Biotechnol 2024; 12:1410230. [PMID: 38854857 PMCID: PMC11157067 DOI: 10.3389/fbioe.2024.1410230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 05/06/2024] [Indexed: 06/11/2024] Open
Abstract
Background Dental implants have become an increasingly popular option for replacing missing teeth, and the prevalence of peri-implantitis has also increased, which is expected to become a public health problem worldwide and cause high economic and health burdens. This scenario highlights the need for new therapeutic options to treat peri-implantitis. Methods In this study, we proposed a novel sono-responsive antibacterial nanosystem co-loaded with metformin (Met) and bone morphogenetic protein-2 (BMP-2) to promote efficacy in treating peri-implantitis. We introduced the zeolitic imidazolate framework-8 (ZIF-8) as a carrier for hematoporphyrin monomethyl ether (HMME) to enhance the antibacterial effect of sonodynamic antibacterial therapy and tested its reactive oxygen species (ROS) production efficiency and bactericidal effect in vitro. Afterward, HMME-loaded ZIF-8, BMP-2-loaded polylactic acid-glycolic acid (PLGA), and Met were incorporated into gelatin methacryloyl (GelMA) hydrogels to form HMME@ZIF-8/Met/BMP-2@PLGA/GelMA composite hydrogels, and the biocompatibility of which was determined in vitro and in vivo. A bacterial-induced peri-implantitis model in the maxilla of rats was established to detect the effects of the composite hydrogels with adjunctive use of ultrasound on regulating inflammation and promoting bone tissue repair in vivo. Results The results indicated that HMME@ZIF-8 with ultrasound stimulation demonstrated more better ROS production efficiency and antimicrobial efficacy. The composite hydrogels had good biocompatibility. Ultrasound-assisted application of the composite hydrogels reduced the release of the inflammatory factors IL-6 and TNF-α and reduced bone loss around the implant in rats with bacterial-induced peri-implantitis. Conclusion Our observations suggest that HMME@ZIF-8 may be a new good sonosensitizer material for sonodynamic antibacterial therapy. The use of HMME@ZIF-8/Met/BMP-2@PLGA/GelMA composite hydrogels in combination with ultrasound can provide a novel option for treating peri-implantitis in the future.
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Affiliation(s)
- Bo Hu
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Wang Qiao
- Department of Stomatology, Shapingba Hospital Affiliated to Chongqing University, Chongqing, China
| | - Yang Cao
- Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of Ultrasound Imaging, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoming Fu
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Jinlin Song
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
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Canullo L, Donato A, Savadori P, Radovanovic S, Iacono R, Rakic M. Effect of argon plasma abutment activation on soft tissue healing: RCT with histological assessment. Clin Implant Dent Relat Res 2024; 26:226-236. [PMID: 37853303 DOI: 10.1111/cid.13286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 09/27/2023] [Accepted: 09/30/2023] [Indexed: 10/20/2023]
Abstract
OBJECTIVE To assess the peri-implant soft tissue profiles between argon plasma treatment (PT) and non-treated (NPT) healing abutments by comparing clinical and histological parameters 2 months following abutment placement. MATERIALS AND METHODS Thirty participants were randomly assigned to argon-plasma treatment abutments group (PT) or non-treated abutments (NPT) group. Two months after healing abutment placement, soft peri-implant tissues and abutment were harvested, and histological and clinical parameters including plaque index, bleeding on probing, and keratinized mucosa diameter (KM) were assessed. Specialized stainings (hematoxylin-eosin and picrocirious red) coupled with immunohistochemistry (vimentin, collagen, and CK10) were performed to assess soft tissue inflammation and healing, and the collagen content keratinization. In addition to standard statistical methods, machine learning algorithms were applied for advanced soft tissue profiling between the test and control groups. RESULTS PT group showed lower plaque accumulation and inflammation grade (6.71% vs. 13.25%, respectively; p-value 0.02), and more advanced connective tissue healing and integration compared to NPT (31.77% vs. 23.3%, respectively; p = 0.009). In the control group, more expressed keratinization was found compared to the PT group, showing significantly higher CK10 (>47.5%). No differences in KM were found between the groups. SIGNIFICANCE PT seems to be a promising protocol for guided peri-implant soft tissue morphogenesis reducing plaque accumulation and inflammation, and stimulating collagen and soft tissue but without effects on epithelial tissues and keratinization.
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Affiliation(s)
- Luigi Canullo
- Department of Surgical Sciences (DISC), University of Genoa, Genova, Italy
- Department of Periodontology, University of Bern, Bern, Switzerland
| | | | - Paolo Savadori
- Department of Biomedical, Surgical and Dental Sciences, Università Degli Studi di Milano, Milan, Italy
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Maxillo-Facial Surgery and Dental Unit, Milan, Italy
| | - Sandro Radovanovic
- Faculty of Organizational Sciences, University of Belgrade, Belgrade, Serbia
| | - Roberta Iacono
- Department of Oral and Maxillo-facial Sciences, Sapienza University of Rome, Rome, Italy
| | - Mia Rakic
- Facultad de Odontologia, Etiology and Therapy of Periodontal Diseases (ETEP) Research Group, Universidad Complutense de Madrid, Madrid, Spain
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Zhou W, Liang J, Huang X, Weir MD, Masri R, Oates TW, Xu HHK, Cheng L. Novel antibacterial titanium implant healing abutment with dimethylaminohexadecyl methacrylate to combat implant-related infections. Dent Mater 2024; 40:244-253. [PMID: 37981511 DOI: 10.1016/j.dental.2023.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/05/2023] [Accepted: 11/06/2023] [Indexed: 11/21/2023]
Abstract
OBJECTIVE Implant-related infections from the adhesion and proliferation of dental plaque are a major challenge for dental implants. The objectives of this study were to: (1) develop novel antibacterial titanium (Ti) healing abutment; (2) investigate the inhibition of implant infection-related pathogenic bacteria and saliva-derived biofilm, and evaluate the biocompatibility of the new material for the first time. METHODS Dimethylaminohexadecyl methacrylate (DMAHDM) and hydroxyapatite (HAP) were polymerized via polydopamine (PDA) on Ti. Staphylococcus aureus (S. aureus), Streptococcus sanguinis (S. sanguinis) and human saliva-derived biofilms were tested. After 4 weeks of DMAHDM release, the antibacterial efficacy of the DMAHDM remaining on Ti surface and the DMADHM in medium was tested. Biocompatibility was determined using human gingival fibroblasts (HGFs) and periodontal ligament stem cells (PDLSCs). RESULTS The DMAHDM-loaded coating filled into the nano-voids in Ti surfaces. The modified Ti showed potent antibacterial activity, reducing the CFU of S. aureus, S. sanguinis and saliva-derived biofilms by 8, 7 and 4 log, respectively (P < 0.05). After 4 weeks of release, the modified Ti was still able to reduce S. aureus and S. sanguinis biofilm CFU by 1-3 log (P < 0.05). This provided strong antibacterial function for more than 4 weeks, which were the high-risk period for implant infections. The new material showed excellent biocompatibility when compared to control (P > 0.05). CONCLUSION Novel DMAHDM-loaded Ti healing abutment had strong antibacterial effects, reducing biofilm CFUs by orders of magnitude, and lasting for over four weeks to cover the high-risk period for implant infections. The novel antibacterial Ti is promising to combat implant-related infections in dental, craniofacial and orthopedic applications.
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Affiliation(s)
- Wen Zhou
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou 350002, China; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases & Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu 610041, China; Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Jingou Liang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases & Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu 610041, China; Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Xiaoyu Huang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases & Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu 610041, China; Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, China
| | - Michael D Weir
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Radi Masri
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Thomas W Oates
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Hockin H K Xu
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases & Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu 610041, China.
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Hayashi R, Takao S, Komasa S, Sekino T, Kusumoto T, Maekawa K. Effects of Argon Gas Plasma Treatment on Biocompatibility of Nanostructured Titanium. Int J Mol Sci 2023; 25:149. [PMID: 38203320 PMCID: PMC10779263 DOI: 10.3390/ijms25010149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024] Open
Abstract
In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site.
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Affiliation(s)
- Rina Hayashi
- Department of Removable Prosthodontics and Occlusion, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata 573-1121, Osaka, Japan; (R.H.); (S.T.); (K.M.)
| | - Seiji Takao
- Department of Removable Prosthodontics and Occlusion, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata 573-1121, Osaka, Japan; (R.H.); (S.T.); (K.M.)
| | - Satoshi Komasa
- Department of Removable Prosthodontics and Occlusion, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata 573-1121, Osaka, Japan; (R.H.); (S.T.); (K.M.)
| | - Tohru Sekino
- Department of Advanced Hard Materials, SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Osaka, Japan;
| | - Tetsuji Kusumoto
- Department of Oral Health Engineering, Faculty of Health Sciences, Osaka Dental University, 1-4-4, Makino-honmachi, Hirakata 573-1121, Osaka, Japan;
| | - Kenji Maekawa
- Department of Removable Prosthodontics and Occlusion, Osaka Dental University, 8-1 Kuzuha-hanazono-cho, Hirakata 573-1121, Osaka, Japan; (R.H.); (S.T.); (K.M.)
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Fialho L, Costa-Barbosa A, Sampaio P, Carvalho S. Effects of Zn-ZnO Core-Shell Nanoparticles on Antimicrobial Mechanisms and Immune Cell Activation. ACS APPLIED NANO MATERIALS 2023; 6:17149-17160. [PMID: 37772266 PMCID: PMC10526648 DOI: 10.1021/acsanm.3c03241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 08/22/2023] [Indexed: 09/30/2023]
Abstract
The deposition of zinc-zinc oxide nanoparticles (Zn-ZnO NPs) onto porous Ta2O5 surfaces enriched with calcium phosphate by DC magnetron sputtering was investigated to improve the surface antimicrobial activity without triggering an inflammatory response. Different sizes and amounts of Zn NPs obtained by two optimized different depositions and an additional thin carbon (C) layer deposited over the NPs were explored. The deposition of the Zn NPs and the C layer mitigates the surface porosity, increasing the surface hydrophobicity and decreasing the surface roughness. The possible antimicrobial effect and immune system activation of Zn-ZnO NPs were investigated in Candida albicans and macrophage cells, respectively. It was found that the developed surfaces displayed a fungistatic behavior, as they impair the growth of C. albicans between 5 and 24 h of culture. This behavior was more evident on the surfaces with bigger NPs and the highest amounts of Zn. The same trend was observed in both reactive oxygen species (ROS) generation and loss of C. albicans' membrane integrity. After 24 h of culture, cell toxicity was also dependent on the amount of the NPs. Cell toxicity was observed in surfaces with the highest amount of Zn NPs and with the C layer, while cells were able to grow without any signs of cytotoxicity in the porous surfaces with the lowest amount of NPs. The same Zn-dose-dependent behavior was noticed in the TNF-α production. The Zn-containing surfaces show a vastly inferior cytokine secretion than the lipopolysaccharide (LPS)-stimulated cells, indicating that the modified surfaces do not induce an inflammatory response from macrophage cells. This study provides insights for understanding the Zn amount threshold that allows a simultaneous inhibition of the fungi growth with no toxic effect and the main antimicrobial mechanisms of Zn-ZnO NPs, contributing to future clinical applications.
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Affiliation(s)
- Luísa Fialho
- CEMMPRE,
Departamento de Engenharia Mecânica, Universidade de Coimbra, 3030-788 Coimbra, Portugal
| | - Augusto Costa-Barbosa
- CBMA,
Departamento de Biologia, Campus de Gualtar, Universidade do Minho, 4710-057 Braga, Portugal
| | - Paula Sampaio
- CBMA,
Departamento de Biologia, Campus de Gualtar, Universidade do Minho, 4710-057 Braga, Portugal
| | - Sandra Carvalho
- CEMMPRE,
Departamento de Engenharia Mecânica, Universidade de Coimbra, 3030-788 Coimbra, Portugal
- IPN
− LED & MAT − Instituto Pedro Nunes, Rua Pedro Nunes, 3030-199 Coimbra, Portugal
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