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Hernández-Escobar D, Pajares-Chamorro N, Chatzistavrou X, Hankenson KD, Hammer ND, Boehlert CJ. Tailored Coatings for Enhanced Performance of Zinc-Magnesium Alloys in Absorbable Implants. ACS Biomater Sci Eng 2024; 10:338-354. [PMID: 38109649 DOI: 10.1021/acsbiomaterials.3c01255] [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] [Indexed: 12/20/2023]
Abstract
Absorbable metals exhibit potential for next-generation temporary medical implants, dissolving safely in the body during tissue healing and regeneration. Their commercial incorporation could substantially diminish the need for additional surgeries and complications that are tied to permanent devices. Despite extensive research on magnesium (Mg) and iron (Fe), achieving the optimal combination of mechanical properties, biocompatibility, and controlled degradation rate for absorbable implants remains a challenge. Zinc (Zn) and Zn-based alloys emerged as an attractive alternative for absorbable implants, due to favorable combination of in vivo biocompatibility and degradation behavior. Moreover, the development of suitable coatings can enhance their biological characteristics and tailor their degradation process. In this work, four different biodegradable coatings (based on zinc phosphate (ZnP), collagen (Col), and Ag-doped bioactive glass nanoparticles (AgBGNs)) were synthesized by chemical conversion, spin-coating, or a combination of both on Zn-3Mg substrates. This study assessed the impact of the coatings on in vitro degradation behavior, cytocompatibility, and antibacterial activity. The ZnP-coated samples demonstrated controlled weight loss and a decreased corrosion rate over time, maintaining a physiological pH. Extracts from the uncoated, ZnP-coated, and Col-AgBGN-coated samples showed higher cell viability with increasing concentration. Bacterial viability was significantly impaired in all coated samples, particularly in the Col-AgBGN coating. This study showcases the potential of a strategic material-coating combination to effectively tackle multiple challenges encountered in current medical implant technologies by modifying the properties of absorbable metals to tailor patient treatments.
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Affiliation(s)
- David Hernández-Escobar
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Natalia Pajares-Chamorro
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Xanthippi Chatzistavrou
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Kurt D Hankenson
- Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan 48104, United States
| | - Neal D Hammer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824, United States
| | - Carl J Boehlert
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
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2
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Harrop ACF, Tupally KR, Pandey P, Parekh HS. Opportunities for Bioactive Glass in Gastrointestinal Conditions: A Review of Production Methodologies, Morphology, Composition, and Performance. Mol Pharm 2023; 20:5954-5980. [PMID: 37962352 DOI: 10.1021/acs.molpharmaceut.3c00188] [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] [Indexed: 11/15/2023]
Abstract
Bioactive glasses (BGs) are widely used in orthopedic and dental applications for their ability to stimulate endogenous bone formation and regeneration. BG applications more recently broadened to include soft tissue conditions, based on their ability to stimulate angiogenesis, soft tissue regeneration, and wound healing. Sol-gel synthesis has helped facilitate this expansion, allowing formulators to tailor the morphological characteristics of the BG matrix. The effectiveness of BGs in skin wound healing is viewed as a gateway for their use as both a therapeutic and drug delivery platform in other soft tissue applications, notably gastrointestinal (GI) applications, which form the focus of this review. Recent changes in international guidelines for GI conditions shifted clinical objectives from symptom management to mucosal wound healing. The additional scrutiny of proton pump inhibitor (PPI) safety, increasing burden of disease, and financial costs associated with gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), and inflammatory bowel disease (IBD) open new clinical possibilities for BG. This narrative literature review intersects materials engineering, formulation science, and clinical practice, setting it apart from prior literature. Broadly, current evidence for BG applications in GI conditions is sparse and under-developed, which this review directly addresses. It explores and synthesizes evidence that supports the potential use of sol-gel-derived BG for the efficacious treatment of soft tissue applications, with specific reference to GI conditions. An overview with comparative analysis of current BG synthesis techniques and associated challenges is presented, and influences of composition, biologically active ions, and morphological characteristics in soft tissue applications are explored. To contextualize this, sol-gel-derived BGs are proposed as a dual, tailorable therapeutic and drug delivery platform for upper and lower GI conditions. Future directions for this largely untapped area of translational research are also proposed, based on extant literature.
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Affiliation(s)
- Angus C F Harrop
- The University of Queensland, School of Pharmacy, The Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, Queensland 4102, Australia
| | - Karnaker R Tupally
- The University of Queensland, School of Pharmacy, The Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, Queensland 4102, Australia
| | - Preeti Pandey
- The University of Queensland, School of Pharmacy, The Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, Queensland 4102, Australia
| | - Harendra S Parekh
- The University of Queensland, School of Pharmacy, The Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, Queensland 4102, Australia
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3
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Pajares-Chamorro N, Hernández-Escobar S, Wagley Y, Acevedo P, Cramer M, Badylak S, Hammer ND, Hardy J, Hankenson K, Chatzistavrou X. Silver-releasing bioactive glass nanoparticles for infected tissue regeneration. BIOMATERIALS ADVANCES 2023; 154:213656. [PMID: 37844416 DOI: 10.1016/j.bioadv.2023.213656] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/30/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023]
Abstract
Bacterial infections represent a formidable challenge, often leaving behind significant bone defects post-debridement and necessitating prolonged antibiotic treatments. The rise of antibiotic-resistant bacterial strains further complicates infection management. Bioactive glass nanoparticles have been presented as a promising substitute for bone defects and as carriers for therapeutic agents against microorganisms. Achieving consistent incorporation of ions into BGNs has proven challenging and restricted to a maximum ion concentration, especially when reducing the particle size. This study presents a notable achievement in the synthesis of 10 nm-sized Ag-doped bioactive glass nanoparticles (Ag-BGNs) using a modified yet straightforward Stöber method. The successful incorporation of essential elements, including P, Ca, Al, and Ag, into the glass structure at the intended concentrations (i.e., CaO wt% above 20 %) was confirmed by EDS, signifying a significant advancement in nanoscale biomaterial engineering. While exhibiting a spherical morphology and moderate dispersity, these nanoparticles tend to form submicron-sized aggregates outside of a solution state. The antibacterial effectiveness against MRSA was established across various experimental conditions, with Ag-BGNs effectively sterilizing planktonic bacteria without the need for antibiotics. Remarkably, when combined with oxacillin or fosfomycin, Ag-BGNs demonstrated a potent synergistic effect, restoring antibacterial capabilities against MRSA strains resistant to these antibiotics when used alone. Ag-BGNs exhibited potential in promoting human mesenchymal stromal cell proliferation, inducing the upregulation of osteoblast gene markers, and significantly contributing to bone regeneration in mice. This innovative synthesis protocol holds substantial promise for the development of biomaterials dedicated to the regeneration of infected tissue.
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Affiliation(s)
- Natalia Pajares-Chamorro
- Department of Chemical Engineering and Material Science, College of Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Sandra Hernández-Escobar
- Department of Chemical Engineering and Material Science, College of Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Yadav Wagley
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Parker Acevedo
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Madeline Cramer
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen Badylak
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Neal D Hammer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Jonathan Hardy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA; Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI 48824, USA
| | - Kurt Hankenson
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Xanthippi Chatzistavrou
- Department of Chemical Engineering and Material Science, College of Engineering, Michigan State University, East Lansing, MI 48824, USA; Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
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Leveque M, Bekhouche M, Farges JC, Aussel A, Sy K, Richert R, Ducret M. Bioactive Endodontic Hydrogels: From Parameters to Personalized Medicine. Int J Mol Sci 2023; 24:14056. [PMID: 37762359 PMCID: PMC10531297 DOI: 10.3390/ijms241814056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Regenerative endodontic procedures (REPs) aim at recreating dental pulp tissue using biomaterials such as hydrogels. Their bioactivity is mostly related to the nature of biomolecules or chemical compounds that compose the endodontic hydrogel. However, many other parameters, such as hydrogel concentration, bioactive molecules solubility, and apex size, were reported to influence the reciprocal host-biomaterial relationship and hydrogel behavior. The lack of knowledge regarding these various parameters, which should be considered, leads to the inability to predict the clinical outcome and suggests that the biological activity of endodontic hydrogel is impossible to anticipate and could hinder the bench-to-bedside transition. We describe, in this review, that most of these parameters could be identified, described, and studied. A second part of the review lists some challenges and perspectives, including development of future mathematical models that are able to explain, and eventually predict, the bioactivity of endodontic hydrogel used in a clinical setting.
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Affiliation(s)
- Marianne Leveque
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR 5305 CNRS/UCBL, 69007 Lyon, France; (M.L.); (M.B.); (J.-C.F.)
| | - Mourad Bekhouche
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR 5305 CNRS/UCBL, 69007 Lyon, France; (M.L.); (M.B.); (J.-C.F.)
| | - Jean-Christophe Farges
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR 5305 CNRS/UCBL, 69007 Lyon, France; (M.L.); (M.B.); (J.-C.F.)
- Faculté d’Odontologie, Université Claude Bernard Lyon 1, Université de Lyon, 69008 Lyon, France; (K.S.); (R.R.)
- Service d’Odontologie, Hospices Civils de Lyon, 69007 Lyon, France
| | - Audrey Aussel
- BIOTIS—Laboratory for the Bioengineering of Tissues (UMR Inserm 1026), University of Bordeaux, Inserm, 33076 Bordeaux, France;
- UFR d’Odontologie, Université de Bordeaux, 33600 Bordeaux, France
- CHU de Bordeaux, Pôle de Médecine et Chirurgie Bucco-Dentaire, 33076 Bordeaux, France
| | - Kadiatou Sy
- Faculté d’Odontologie, Université Claude Bernard Lyon 1, Université de Lyon, 69008 Lyon, France; (K.S.); (R.R.)
- Service d’Odontologie, Hospices Civils de Lyon, 69007 Lyon, France
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Claude Bernard Lyon 1, 69622 Villeurbanne, France
| | - Raphaël Richert
- Faculté d’Odontologie, Université Claude Bernard Lyon 1, Université de Lyon, 69008 Lyon, France; (K.S.); (R.R.)
- Service d’Odontologie, Hospices Civils de Lyon, 69007 Lyon, France
| | - Maxime Ducret
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR 5305 CNRS/UCBL, 69007 Lyon, France; (M.L.); (M.B.); (J.-C.F.)
- Faculté d’Odontologie, Université Claude Bernard Lyon 1, Université de Lyon, 69008 Lyon, France; (K.S.); (R.R.)
- Service d’Odontologie, Hospices Civils de Lyon, 69007 Lyon, France
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Yang TY, Chern GI, Wang WH, Shih CJ. Synthesis, Characterization, and Bioactivity of Mesoporous Bioactive Glass Codoped with Zinc and Silver. Int J Mol Sci 2023; 24:13679. [PMID: 37761992 PMCID: PMC10531463 DOI: 10.3390/ijms241813679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 08/30/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
Due to the overconsumption of antimicrobials, antibiotic-resistant bacteria have become a critical health issue worldwide, especially methicillin-resistant S. aureus (MRSA) and vancomycin-resistant E. faecalis (VRE). Recently, many efforts have been made to load metals into bioactive glasses to enhance the multifunctionality of materials, such as antibacterial and osteoinductive functions. Zinc has been documented to stimulate the gene expression of various regulatory factors in bone cells. Meanwhile, previous studies have reported that silver and zinc could be a promising antibacterial combination with synergistic antimicrobial effects. Here, we sought to develop a biomaterial coreleasing zinc and silver, designated 80S-ZnAg, and to evaluate its antibacterial activity and biocompatibility. The textural analyses demonstrated different coreleasing patterns of zinc and silver for the materials. The chemical characterization revealed that the zinc in 80S-ZnAg could be the network modifier when its molar ratio was high, releasing more zinc; zinc could also be the network former when its molar ratio was low, showing an extremely low rate of release. However, the ICP results for 80S-Zn3Ag2 demonstrated up to 7.5 ppm of zinc and 67.6 ppm of silver. Among all the 80S-ZnAg materials, 80S-Zn3Ag2 demonstrated more marked antibacterial activity against MRSA and VRE than the others, with inhibition zones of 11.5 and 13.4 mm, respectively. The cytotoxicity assay exhibited nearly 90% cell viability at 20 mg/mL of 80-Zn3Ag2. Further clinical study is needed to develop an innovative biomaterial to address the issue of antibiotic resistance.
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Affiliation(s)
- Tsung-Ying Yang
- Department of Medical Laboratory Science, I-Shou University, Kaohsiung 84001, Taiwan;
- Research Organization for Nano and Life Innovation, Future Innovation Institute, Waseda University, Tokyo 162-0041, Japan
- Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan
- School of Education, Waseda University, Tokyo 169-8050, Japan
| | - Guann-In Chern
- Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Wei-Hsun Wang
- Department of Orthopedic Surgery, Changhua Christian Hospital, Changhua 50006, Taiwan
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung 40227, Taiwan
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Chemical Engineering, National United University, Miaoli 36063, Taiwan
- Department of Golden-Ager Industry Management, Chaoyang University of Technology, Taichung 41349, Taiwan
- Department of Medical Imaging and Radiology, Shu-Zen Junior College of Medicine and Management, Kaohsiung 82144, Taiwan
| | - Chi-Jen Shih
- Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
- Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
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6
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Zareei A, Kasi V, Thornton A, Rivera UH, Sawale M, Maruthamuthu MK, He Z, Nguyen J, Wang H, Mishra DK, Rahimi R. Non-destructive processing of silver containing glass ceramic antibacterial coating on polymeric surgical mesh surfaces. NANOSCALE 2023; 15:11209-11221. [PMID: 37345366 PMCID: PMC10552273 DOI: 10.1039/d3nr01317k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
Surgical meshes composed of bioinert polymers such as polypropylene are widely used in millions of hernia repair procedures to prevent the recurrence of organ protrusion from the damaged abdominal wall. However, post-operative mesh infection remains a significant complication, elevating hernia recurrence risks from 3.6% to 10%, depending on the procedure type. While attempts have been made to mitigate these infection-related complications by using antibiotic coatings, the rise in antibiotic-resistant bacterial strains threatens their effectiveness. Bioactive glass-ceramics featuring noble metals, notably silver nanoparticles (AgNPs), have recently gained traction for their wide antibacterial properties and biocompatibility. Yet, conventional methods of synthesizing and coating of such materials often require high temperatures, thus making them impractical to be implemented on temperature-sensitive polymeric substrates. To circumvent this challenge, a unique approach has been explored to deposit these functional compounds onto temperature-sensitive polypropylene mesh (PP-M) surfaces. This approach is based on the recent advancements in cold atmospheric plasma (CAP) assisted deposition of SiO2 thin films and laser surface treatment (LST), enabling the selective heating and formation of functional glass-ceramic compounds under atmospheric conditions. A systematic study was conducted to identify optimal LST conditions that resulted in the effective formation of a bioactive glass-ceramic structure without significantly altering the chemical and mechanical properties of the underlying PP-M (less than 1% change compared to the original properties). The developed coating with optimized processing conditions demonstrated high biocompatibility and persistent antibacterial properties (>7 days) against both Gram-positive and Gram-negative bacteria. The developed process is expected to provide a new stepping stone towards depositing a wide range of functional bioceramic coatings onto different implant surfaces, thereby decreasing their risk of infection and associated complications.
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Affiliation(s)
- Amin Zareei
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA.
- Birck Nanotechnology Canter, Purdue University, West Lafayette, IN 47907, USA
| | - Venkat Kasi
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA.
- Birck Nanotechnology Canter, Purdue University, West Lafayette, IN 47907, USA
| | - Allison Thornton
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA.
- Birck Nanotechnology Canter, Purdue University, West Lafayette, IN 47907, USA
| | - Ulisses Heredia Rivera
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA.
- Birck Nanotechnology Canter, Purdue University, West Lafayette, IN 47907, USA
| | - Manoj Sawale
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA
| | - Murali Kannan Maruthamuthu
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Zihao He
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Juliane Nguyen
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Haiyan Wang
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA.
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Dharmendra K Mishra
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA
| | - Rahim Rahimi
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA.
- Birck Nanotechnology Canter, Purdue University, West Lafayette, IN 47907, USA
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA
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Pajares-Chamorro N, Lensmire JM, Hammer ND, Hardy JW, Chatzistavrou X. Unraveling the mechanisms of inhibition of silver-doped bioactive glass-ceramic particles. J Biomed Mater Res A 2022; 111:975-994. [PMID: 36583930 DOI: 10.1002/jbm.a.37482] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/31/2022]
Abstract
Infections are a major concern in orthopedics. Antibacterial agents such as silver ions are of great interest as broad-spectrum biocides and have been incorporated into bioactive glass-ceramic particles to control the release of ions within a therapeutic concentration and provide tissue regenerative properties. In this work, the antibacterial capabilities of silver-doped bioactive glass (Ag-BG) microparticles were explored to reveal the unedited mechanisms of inhibition against methicillin-resistant Staphylococcus aureus (MRSA). The antibacterial properties were not limited to the delivery of silver ions but rather a combination of antibacterial degradation by-products. For example, nano-sized debris punctured holes in bacteria membranes, osmotic effects, and reactive oxygen species causing oxidative stress and almost 40% of the inhibition. Upon successive Ag-BG treatments, MRSA underwent phenotypic and genomic mutations which were not only insufficient to develop resistance but instead, the clones became more sensitive as the treatment was re-delivered. Additionally, the unprecedented restorative functionality of Ag-BG allowed the effective use of antibiotics that MRSA resists. The synergy mechanism was mainly identified for combinations targeting cell-wall activity and their action was proven in biofilm-like and virulent conditions. Unraveling these mechanisms may offer new insights into how to tailor healthcare materials to prevent or debilitate infections and join the fight against antibiotic resistance in clinical cases.
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Affiliation(s)
- Natalia Pajares-Chamorro
- Department of Chemical Engineering and Material Science, College of Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Josh M Lensmire
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Neal D Hammer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Jonathan W Hardy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA.,Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, Michigan, USA
| | - Xanthippi Chatzistavrou
- Department of Chemical Engineering and Material Science, College of Engineering, Michigan State University, East Lansing, Michigan, USA.,Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece
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8
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Pajares-Chamorro N, Hammer ND, Chatzistavrou X. Materials for restoring lost Activity: Old drugs for new bugs. Adv Drug Deliv Rev 2022; 186:114302. [PMID: 35461913 DOI: 10.1016/j.addr.2022.114302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 04/04/2022] [Accepted: 04/12/2022] [Indexed: 11/01/2022]
Abstract
The escalation of bacterial resistance to conventional medical antibiotics is a serious concern worldwide. Improvements to current therapies are urgently needed to address this problem. The synergistic combination of antibiotics with other agents is a strategic solution to combat multi-drug-resistant bacteria. Although these combinations decrease the required high dosages and therefore, reduce the toxicity of both agents without compromising the bactericidal effect, they cannot stop the development of further resistance. Recent studies have shown certain elements restore the ability of antibiotics to destroy bacteria that have acquired resistance to them. Due to these synergistic activities, organic and inorganic molecules have been investigated with the goal of restoring antibiotics in new approaches that mitigate the risk of expanding resistance. Herein, we summarize recent studies that restore antibiotics once thought to be ineffective, but have returned to our armamentarium through innovative, combinatorial efforts. A special focus is placed on the mechanisms that allow the synergistic combinations to combat bacteria. The promising data that demonstrated restoration of antimicrobials, supports the notion to find more combinations that can combat antibiotic-resistant bacteria.
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9
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Synergistic Antibacterial Effect of Casein-AgNPs Combined with Tigecycline against Acinetobacter baumannii. Polymers (Basel) 2021; 13:polym13091529. [PMID: 34068784 PMCID: PMC8126194 DOI: 10.3390/polym13091529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 01/23/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) is a common and challenging pathogen of nosocomial infections, due to its ability to survive on inanimate objects, desiccation tolerance, and resistance to disinfectants. In this study, we investigated an antibacterial strategy to combat A. baumannii via the combination of antibiotics and silver protein. This strategy used a functional platform consisting of silver nanoparticles (AgNPs) resurrected from silver-based calcium thiophosphate (SSCP) through casein and arginine. Then, the silver protein was combined with tigecycline, the first drug in glycylcycline antibiotic, to synergistically inhibit the viability of A. baumannii. The synergistic antibacterial activity was confirmed by the 96-well checkerboard method to determine their minimum inhibitory concentrations (MIC) and calculated for the combination index (CI). The MIC of the combination of silver protein and tigecycline (0.31 mg/mL, 0.16 µg/mL) was significantly lower than that of the individual MIC, and the CI was 0.59, which indicates a synergistic effect. Consequently, we integrated the detailed synergistic antibacterial properties when silver protein was combined with tigecycline. The result could make for a promising approach for the treatment of A. baumannii.
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Zheng K, Sui B, Ilyas K, Boccaccini AR. Porous bioactive glass micro- and nanospheres with controlled morphology: developments, properties and emerging biomedical applications. MATERIALS HORIZONS 2021; 8:300-335. [PMID: 34821257 DOI: 10.1039/d0mh01498b] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In recent years, porous bioactive glass micro/nanospheres (PBGSs) have emerged as attractive biomaterials in various biomedical applications where such engineered particles provide suitable functions, from tissue engineering to drug delivery. The design and synthesis of PBGSs with controllable particle size and pore structure are critical for such applications. PBGSs have been successfully synthesized using melt-quenching and sol-gel based methods. The morphology of PBGSs is controllable by tuning the processing parameters and precursor characteristics during the synthesis. In this comprehensive review on PBGSs, we first overview the synthesis approaches for PBGSs, including both melt-quenching and sol-gel based strategies. Sol-gel processing is the primary technology used to produce PBGSs, allowing for control over the chemical compositions and pore structure of particles. Particularly, the influence of pore-forming templates on the morphology of PBGSs is highlighted. Recent progress in the sol-gel synthesis of PBGSs with sophisticated pore structures (e.g., hollow mesoporous, dendritic fibrous mesoporous) is also covered. The challenges regarding the control of particle morphology, including the influence of metal ion precursors and pore expansion, are discussed in detail. We also highlight the recent achievements of PBGSs in a number of biomedical applications, including bone tissue regeneration, wound healing, therapeutic agent delivery, bioimaging, and cancer therapy. Finally, we conclude with our perspectives on the directions of future research based on identified challenges and potential new developments and applications of PBGSs.
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Affiliation(s)
- Kai Zheng
- Institute of Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
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11
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Pajares-Chamorro N, Wagley Y, Maduka CV, Youngstrom DW, Yeger A, Badylak SF, Hammer ND, Hankenson K, Chatzistavrou X. Silver-doped bioactive glass particles for in vivo bone tissue regeneration and enhanced methicillin-resistant Staphylococcus aureus (MRSA) inhibition. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 120:111693. [PMID: 33545854 PMCID: PMC8168684 DOI: 10.1016/j.msec.2020.111693] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 11/18/2022]
Abstract
Infection is a significant risk factor for failed healing of bone and other tissues. We have developed a sol-gel (solution-gelation) derived bioactive glass doped with silver ions (Ag-BG), tailored to provide non-cytotoxic antibacterial activity while significantly enhancing osteoblast-lineage cell growth in vitro and bone regeneration in vivo. Our objective was to engineer a biomaterial that combats bacterial infection while maintaining the capability to promote bone growth. We observed that Ag-BG inhibits bacterial growth and potentiates the efficacy of conventional antibiotic treatment. Ag-BG microparticles enhance cell proliferation and osteogenic differentiation in human bone marrow stromal cells (hBMSC) in vitro. Moreover, in vivo tests using a calvarial defect model in mice demonstrated that Ag-BG microparticles induce bone regeneration. This novel system with dual biological and advanced antibacterial properties is a promising therapeutic for combating resistant bacteria while triggering new bone formation.
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Affiliation(s)
- Natalia Pajares-Chamorro
- Department of Chemical Engineering and Materials Science, College of Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Yadav Wagley
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Chima V Maduka
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA; Institute for Quantitative Health Sciences and Technology, Michigan State University, East Lansing, MI 48824, USA; Comparative Medicine and Integrative Biology, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Daniel W Youngstrom
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Alyssa Yeger
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Stephen F Badylak
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Neal D Hammer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Kurt Hankenson
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI 48103, USA
| | - Xanthippi Chatzistavrou
- Department of Chemical Engineering and Materials Science, College of Engineering, Michigan State University, East Lansing, MI 48824, USA.
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12
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Marsh AC, Zhang Y, Poli L, Hammer N, Roch A, Crimp M, Chatzistavrou X. 3D printed bioactive and antibacterial silicate glass-ceramic scaffold by fused filament fabrication. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111516. [PMID: 33255072 DOI: 10.1016/j.msec.2020.111516] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/28/2020] [Accepted: 09/01/2020] [Indexed: 01/14/2023]
Abstract
The fused filament fabrication (FFF) technique was applied for the first time to fabricate novel 3D printed silicate bioactive and antibacterial Ag-doped glass-ceramic (Ag-BG) scaffolds. A novel filament consisting primarily of polyolefin and Ag-BG micro-sized particles was developed and its thermal properties characterized by thermogravimetric analysis (TGA) to define the optimum heat treatment with minimal macrostructural deformation during thermal debinding and sintering. Structural characteristics of the Ag-BG scaffolds were evaluated from macro- to nanoscale using microscopic and spectroscopic techniques. The compressive strength of the Ag-BG scaffolds was found to be in the range of cancellous bone. Bioactivity of the 3D printed Ag-BG scaffolds was evaluated in vitro through immersion in simulated body fluid (SBF) and correlated to the formation of an apatite-like phase. Methicillin-resistant Staphylococcus aureus (MRSA) inoculated with the Ag-BG scaffolds exhibited a significant decrease in viability underscoring a potent anti-MRSA effect. This study demonstrates the potential of the FFF technique for the fabrication of bioactive 3D silicate scaffolds with promising characteristics for orthopedic applications.
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Affiliation(s)
- Adam C Marsh
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA
| | - Yaozhong Zhang
- Electrical & Computer Engineering, Michigan State University, East Lansing, MI, USA
| | - Lucrezia Poli
- Fraunhofer USA Center for Coatings and Diamond Technologies CCD, East Lansing, MI, USA
| | - Neal Hammer
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Aljoscha Roch
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA; Electrical & Computer Engineering, Michigan State University, East Lansing, MI, USA
| | - Martin Crimp
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA
| | - Xanthippi Chatzistavrou
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI, USA.
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13
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Sugiura Y, Obika H, Horie M, Niitsu K, Makita Y. Aesthetic Silver-Doped Octacalcium Phosphate Powders Exhibiting Both Contact Antibacterial Ability and Low Cytotoxicity. ACS OMEGA 2020; 5:24434-24444. [PMID: 33015459 PMCID: PMC7528307 DOI: 10.1021/acsomega.0c02868] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/19/2020] [Indexed: 05/11/2023]
Abstract
Since the introduction of biomaterials, infection has been a serious problem in clinical operations. Although several studies have introduced hybrid materials of calcium phosphate and Ag0 nanoparticles (NPs) that exhibit antibacterial activity, released Ag+ ions and Ag0 NPs are highly cytotoxic and the materials require complex fabrication techniques such as laser irradiation. In this study, we introduce a simple one-pot synthesis method based on crystal-engineering techniques to prepare Ag+-substituted octacalcium phosphate (OCP-Ag) powder that simultaneously exhibits antibacterial activity, little change in color, and low cytotoxicity, thereby overcoming the shortcomings of calcium phosphate as a biomaterial. We used AgNO3-containing (NH4)2HPO4 aqueous solutions as reaction solutions in which Ag+ forms soluble complex [Ag(NH3)2]+ ions that are stable at Ag+ concentrations less than ∼30 mmol/L. Hydrolysis of soluble calcium phosphate in this solution led to pure OCP-Ag when the Ag+ concentration was less than ∼30 mmol/L. Crystallographic analysis showed that Ag+ substituted at the P5 PO4-conjugated sites and was uniformly distributed. When the concentration of Ag+ in the reaction solution was varied, the Ag+ content of the OCP-Ag could be controlled. The obtained OCP-Ag exhibited little color change or Ag+ release when immersed in various media; however, it exhibited contact antibacterial ability toward resident oral bacteria. The prepared OCP-Ag showed no substantial cytotoxicity toward undifferentiated and differentiated MC3T3-E1 cells in assays. Notably, when the Ag+ content in OCP-Ag was optimized (Ag: ∼1 at %), it simultaneously exhibited contact antibacterial ability, little color change, and low cytotoxicity.
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Affiliation(s)
- Yuki Sugiura
- Health
and Medical Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu 761-0895, Kagawa, Japan
| | - Hideki Obika
- Health
and Medical Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu 761-0895, Kagawa, Japan
| | - Masanori Horie
- Health
and Medical Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu 761-0895, Kagawa, Japan
| | - Kodai Niitsu
- Department
of Material Science and Engineering, Kyoto
University, Yoshida-honcho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoji Makita
- Health
and Medical Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu 761-0895, Kagawa, Japan
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14
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Soule LD, Pajares Chomorro N, Chuong K, Mellott N, Hammer N, Hankenson KD, Chatzistavrou X. Sol-Gel-Derived Bioactive and Antibacterial Multi-Component Thin Films by the Spin-Coating Technique. ACS Biomater Sci Eng 2020; 6:5549-5562. [PMID: 33320549 DOI: 10.1021/acsbiomaterials.0c01140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although metallic alloys commonly used as prosthetics are durable and mechanically strong, they are often bioinert and lack antibacterial properties. Implementing a bioactive glass material with antibacterial properties as a coating on a metallic substrate provides mechanical strength and bioactivity, as well as antibacterial properties. Many coating methods have been extensively investigated; however, most of them can be expensive, are difficult to scale up, or do not form thin films, which could prevent their translation to clinical practice. The formation of thin films by spin-coating multi-component solution-gelation (sol-gel)-derived glass with antibacterial and bioactive properties has not been achieved previously. For this study, stainless steel 316L substrates were spin-coated with a sol-gel-derived bioactive and antibacterial glass coating in SiO2 58.3-P2O5 7.1-CaO 25.6-Al2O5 5.4-Ag2O 2.1-Na2O 1.5 wt% system (Ag-BG). A sol-gel processing condition that avoids elemental separation upon spin-coating when sintering happens at below the calcination temperature (500 °C) has been developed. This work demonstrates that silver reduction occurs when the concentrations of other cations such as Ca2+ and Na+ in the solution increase. Increasing the stirring duration time prior to the increase of cations, Ag+ ions are stabilized by aluminum tetrahedra, and their reduction to metallic silver does not occur. This study also shows that large dilution ratios (water:tetraethyl orthosilicate) greater than 25:1, accompanied by long stirring durations, produce morphologically homogeneous coatings. Using this strategy, thin films were formed with antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) biofilm and biological responses that promote eukaryotic cell adhesion and proliferation. In total, the improved synthesis strategy opens new avenues for the development of novel bioactive and antibacterial thin-film coatings, as it reveals the processing characteristics that control the physicochemical and morphological properties of the formed films.
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Affiliation(s)
- Logan D Soule
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Natalia Pajares Chomorro
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Kayla Chuong
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Nathan Mellott
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Neal Hammer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48823, United States
| | - Kurt D Hankenson
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Xanthippi Chatzistavrou
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
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15
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Wang W, Meng Q, Li Q, Liu J, Zhou M, Jin Z, Zhao K. Chitosan Derivatives and Their Application in Biomedicine. Int J Mol Sci 2020; 21:E487. [PMID: 31940963 PMCID: PMC7014278 DOI: 10.3390/ijms21020487] [Citation(s) in RCA: 337] [Impact Index Per Article: 84.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 12/12/2022] Open
Abstract
Chitosan is a product of the deacetylation of chitin, which is widely found in nature. Chitosan is insoluble in water and most organic solvents, which seriously limits both its application scope and applicable fields. However, chitosan contains active functional groups that are liable to chemical reactions; thus, chitosan derivatives can be obtained through the chemical modification of chitosan. The modification of chitosan has been an important aspect of chitosan research, showing a better solubility, pH-sensitive targeting, an increased number of delivery systems, etc. This review summarizes the modification of chitosan by acylation, carboxylation, alkylation, and quaternization in order to improve the water solubility, pH sensitivity, and the targeting of chitosan derivatives. The applications of chitosan derivatives in the antibacterial, sustained slowly release, targeting, and delivery system fields are also described. Chitosan derivatives will have a large impact and show potential in biomedicine for the development of drugs in future.
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Affiliation(s)
- Wenqian Wang
- Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, College of Chemistry Engineering and Materials, Heilongjiang University, Harbin 150080, China; (W.W.); (Q.M.); (Q.L.); (J.L.)
| | - Qiuyu Meng
- Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, College of Chemistry Engineering and Materials, Heilongjiang University, Harbin 150080, China; (W.W.); (Q.M.); (Q.L.); (J.L.)
| | - Qi Li
- Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, College of Chemistry Engineering and Materials, Heilongjiang University, Harbin 150080, China; (W.W.); (Q.M.); (Q.L.); (J.L.)
| | - Jinbao Liu
- Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, College of Chemistry Engineering and Materials, Heilongjiang University, Harbin 150080, China; (W.W.); (Q.M.); (Q.L.); (J.L.)
| | - Mo Zhou
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China;
- Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin 150080, China
| | - Zheng Jin
- Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Heilongjiang Province, College of Chemistry Engineering and Materials, Heilongjiang University, Harbin 150080, China; (W.W.); (Q.M.); (Q.L.); (J.L.)
| | - Kai Zhao
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150080, China;
- Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin 150080, China
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16
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Zirconium Carboxyaminophosphonate Nanosheets as Support for Ag Nanoparticles. MATERIALS 2019; 12:ma12193185. [PMID: 31569365 PMCID: PMC6804208 DOI: 10.3390/ma12193185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/22/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022]
Abstract
A layered insoluble inorganic-organic solid, namely zirconium phosphate glycine-N,N-bismethylphosphonate, was used to prepare dispersions of nanosheets to support active metals such as metallic silver nanoparticles and zinc ions. Zr phosphate-phosphonate microcrystals were first exfoliated with methylamine to produce a stable colloidal dispersion and then the methylamine was removed by treatment with hydrochloric acid. The obtained colloidal dispersion of Zr phosphate-phosphonate nanosheets was used to immobilize silver or zinc cations, via ion exchange, with the acidic protons of the sheets. The layered matrix showed a great affinity for the metal cations up taking all the added cations. The treatment of the dispersions containing silver ions with ethanol yielded metal silver nanoparticles grafted on the surface of the layered host. The samples were characterized by X-ray powder diffraction, elemental analysis transmission electron microscopy, and selected samples were submitted to antimicrobial tests. The nanocomposites based on Ag nanoparticles showed good bactericidal properties against the bacterial reference strain Staphylococcus epidermidis (S. epidermidis).
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17
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Antibacterial Properties of a Novel Zirconium Phosphate-Glycinediphosphonate Loaded with Either Zinc or Silver. MATERIALS 2019; 12:ma12193184. [PMID: 31569362 PMCID: PMC6804034 DOI: 10.3390/ma12193184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/22/2019] [Accepted: 09/24/2019] [Indexed: 12/23/2022]
Abstract
A novel compound consisting of a zirconium phosphate-glycinediphosphonate (ZPGly) has recently been introduced. This 2D-structured material forming nanosheets was exfoliated under appropriate conditions, producing colloidal aqueous dispersions (ZPGly-e) which were then loaded with zinc (Zn/ZPGly) or silver ions. Silver ions were subsequently reduced to produce metallic silver nanoparticles on exfoliated ZPGly nanosheets (Ag@ZPGly). In the search for new anti-infective materials, the present study investigated the properties of colloidal dispersions of ZPGly-e, Zn/ZPGly, and Ag@ZPGly. Ag@ZPGly was found to be a bactericidal material and was assayed to define its minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) on the five most prevalent pathogens of orthopaedic implant infections, namely: Staphylococcus aureus ATCC25923, Staphylococcus epidermidis RP62A, Enterococcus faecalis ATCC29212, Escherichia coli ATCC51739, and Pseudomonas aeruginosa ATCC27853. MIC and MBC were in the range of 125–250 μg/mL and 125–1000 μg/mL, respectively, with E. coli being the most sensitive species. Even colloidal suspensions of exfoliated ZPGly nanosheets and Zn/ZPGly exhibited some intrinsic antibacterial properties, but only at greater concentrations. Unexpectedly, Zn/ZPGly was less active than ZPGly-e.
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