Antibacterial Coatings Research Articles

Efficacy of Zinc Pyrithione as A Novel Anti-Bacterial Coating Agent

Zinc pyrithione (ZPT) is used to prevent microbial degradation and deterioration of manufacturing starting materials such as plastics, polymers, and latexes. The main objective of this study was to evaluate the anti-bacterial properties of ZPT. Currently, there is insufficient data on the effect of ZPT on viability of commonly encountered bacterial pathogens. We tested the efficacy of ZPT manufactured in the form of film rolls as an anti-bacterial protective layer by using the ASTM–recommended protocol on growth of <em>Enterococcus faecalis</em> and <em>Escherichia coli. </em>The bacterial cultures were added to three materials provided by Cao Inc. containing either the base with no active ingredient, ZPT-A, or different amounts of active ingredient, ZPT-B (2.5%) and ZPT-C (5%). Following overnight incubation, bacterial growth was assessed by counting their colony forming units (CFUs). Growth of both <em>E. faecalis</em> and <em>E. coli</em> were strongly inhibited by ZPT-B and ZPT-C relative to growth on the control ZPT-A. Inhibition of <em>E. faecalis</em> was close to complete by ZPT-B and ZPT-C while <em>E. coli</em> growth was inhibited by greater than 95% in a dose dependent manner. This is the first report of zinc pyrithione, here in the form of thin film, inhibiting growth of common bacterial pathogens. ZPT rolls therefore show promise as an effective antibacterial layer for use as a protective barrier, for example on door handles and counters, from clinical to global public health settings.

Biocidal Coatings against Gram-Positive Bacteria from Linear and Branched Polycations: The Decisive Role of the Diffusion Coefficients of Macromolecules

Positively charged polyelectrolytes hold significant potential as materials for creating antibacterial coatings. We examined the physicochemical and mechanical properties of the macromolecules in water solutions and in coatings for the series of branched polyethyleneimine (PEI) and linear polydiallyldimethylammonium chloride (PDADMAC) with different molecular weights. The microbiological study was conducted to analyze the biocidal activity of the polycation solutions and coatings towards foodborne bacteria. While the moisture saturation of the polycationic coatings and biocidal activity did not significantly depend on the chemical nature of charged groups or the molecular weight or architecture of macromolecules, the lowering of the molecular weight of polymers resulted in the loss of cohesive forces in the coatings and to a dramatic loss of stability when being washed off with water. The diffusion coefficient (D0) of macromolecules was identified as a key parameter for the wash-off mechanism. Films formed by molecules with a D0 below 1 × 10−7 cm2/s demonstrated a high resistance to wash-off procedures. We demonstrated that PEI and PDADMAC samples with high molecular weights showed high antimicrobial activity towards L. monocytogenes. Our results highlight the importance of macromolecule characteristics in the development of new biocidal coatings based on polycations.

Antibacterial coatings for electroceutical devices based on PEDOT decorated with gold and silver particles

The continuous progression in the field of electrotherapies implies the development of multifunctional materials exhibiting excellent electrochemical performance and biocompatibility, promoting cell adhesion, and possessing antibacterial properties. Since the conditions favouring the adhesion of mammalian cells are similar to conditions favouring the adhesion of bacterial cells, it is necessary to engineer the surface to exhibit selective toxicity, i.e., to kill or inhibit the growth of bacteria without damaging mammalian tissues. The aim of this paper is to introduce a surface modification approach based on a subsequent deposition of silver and gold particles on the surface of a conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT). The resulting PEDOT-Au/Ag surface is found to possess optimal wettability, roughness, and surface features making it an excellent platform for cell adhesion. By depositing Ag particles on PEDOT surface decorated with Au particles, it is possible to reduce toxic effects of Ag particles, while maintaining their antibacterial activity. Besides, electroactive and capacitive properties of PEDOT-Au/Ag account for its applicability in various electroceutical therapies.

Built-up sodium alginate/chlorhexidine multilayer coating on dental implants with initiating anti-infection and cyto-compatibility sequentially for soft-tissue sealing

Soft-tissue sealing at transmucosal sites is very important for preventing the invasion of pathogens and maintaining the long-term stability and function of dental implants. However, the colonization of oral pathogens on the implant surface and surrounding soft tissues can disturb the early establishment of soft-tissue sealing and even induce peri-implant infection. The purpose of this study was to construct two antibacterial coatings with 5 or 10 sodium alginate/chlorhexidine bilayers on titanium surfaces using layer-by-layer self-assembly technology to promote soft-tissue sealing. The corresponding chemical composition, surface topography, wettability and release behaviour were investigated to prove that the resultant coating of sodium alginate and chlorhexidine was coated on the porous titanium surface. In-vitro and in-vivo antibacterial results showed that both prepared coatings inhibited or killed the bacteria on their surfaces and the surrounding areas to prevent plaque biofilm formation, especially the coating with 10 bilayers. Although both coatings inhibited the initial adhesion of fibroblasts, the cytocompatibility gradually improved with coating degradation. More importantly, both coatings achieved cell adhesion and proliferation in an in-vitro bacterial environment and effectively alleviated bacteria-induced subcutaneous inflammation in-vivo. Therefore, this study demonstrated that the multilayered coating could prevent implant-related infections in the initial stage of implant surgery and then improve soft-tissue integration with implant devices.

ATOMIC FORCE MICROSCOPY OF ANTIBACTERIAL COATINGS PRODUCED FROM POLYCATION AND ITS WATER-SOLUBLE COMPLEX WITH POLYANION

In this work, the morphology and stability of coatings formed from polydiallyldimethylammonium chloride, as well as its complex with sodium polystyrenesulfonate, on the surface of glass and polycarbonate were studied. It has been established that the modifi cation of a polycation with a polyanion makes it possible to increase the resistance of the formed coatings to washing off with water, ensuring the creation of effective antibacterial coatings on various surfaces.

Antibacterial coatings for medical use using in-situ silver nanoparticles in a micro-arc oxidation process

Antibacterial coatings for medical use using in-situ silver nanoparticles in a micro-arc oxidation process

Atomic Force Microscopy of Antibacterial Coatings Produced from Polycation and Its Water-Soluble Complex with Polyanion

Atomic Force Microscopy of Antibacterial Coatings Produced from Polycation and Its Water-Soluble Complex with Polyanion

Flame-retardant, antibacterial and hydrophobic multifunctional coatings on cotton fabrics via layer-by-layer self-assembly

Flame-retardant, antibacterial and hydrophobic multifunctional coatings on cotton fabrics via layer-by-layer self-assembly

Graphene oxide reinforced chitosan/polyvinyl alcohol antibacterial coatings on stainless steel surfaces exhibit superior bioactivity without human cell cytotoxicity

The study proposes an alternative therapeutics to diminish bacterial attachment in biomedical implants by modifying their surface with passive coatings. A uniform, thin-film of chitosan/polyvinyl alcohol/graphene oxide (CS/PVA/GO) was coated on 316 L stainless steel (SS) surface through spread casting followed by solvent evaporation. The abundant anchoring sites available at macromolecular interfaces of chitosan/PVA matrix facilitated a smooth, dense loading of GO. The effect of GO content on physicochemical features, antibacterial potential, and biocompatibility of coatings was thoroughly studied. The hybrid films displayed good adhesion behavior, and UV-protection ability with desired mechanical and thermal stability when coated on SS surface. Coatings manifested a 1.5–1.7 fold rise in antibacterial efficacy against Staphylococcus epidermidis and Staphylococcus aureus and exhibited a permanent biocidal response after 6 h of contact-active behaviour. We investigated a 3-fold generation of reactive oxygen species as the predominant antibacterial mechanism, which diminishes bacterial integrity by inducing protein leakage (8.5–9 fold higher) and suppressing respiratory chain activity as two secondary mechanisms. All coatings with varying GO content appeared non-haemolytic (<2%) with ultra-low cytotoxicity (<29.08%) against human hepatocellular carcinoma (HepG2) and peripheral blood mononuclear cells. The degradation rate of coatings in simulated body fluid exhibited a higher stability, indicated by a lower weight loss (69–78%) and a decrease in pH values as the GO content in coatings increased from 0.05 to 0.15 wt%. Such anti-infective coating is a step forward in inhibiting bacterial colonization on SS surfaces to extend its lifespan.

One-step preparation of novel Ti–Cl bifunctional microstructured surfaces with excellent stem cell compatibility and antibacterial activity

Poor osseointegration of the implant and the occurrence of infection are important causes of endosseous implant failure. The ideal implant material should have excellent osteogenic and antibacterial properties to reduce the time to osseointegration and to prevent the occurrence of infection. Surface microstructures and antibacterial coatings have been successful in improving the biocompatibility of implants. However, due to the limitations of microfabrication techniques and the complexity of material-cell interactions, it is challenging to prepare implants with bifunctional effects.In this study, we prepared a new bifunctional surface containing Ti–Cl microstructure on a titanium alloy substrate by anodic oxidation using an economical and efficient sodium chloride solution as the electrolyte, and then investigated its antibacterial effect and its influence on the biological behavior of human mesenchymal stem cells (hMSCs). The results showed that the anodized surface was distributed with irregular microstructures, and the roughness and wettability of the surface increased compared to the smooth control TC4. The anodized surface can promote the proliferation, adhesion and spreading of hMSCs as well as the secretion of ALP, suggesting a better potential to promote cell osteogenic differentiation. In addition, the chloride formed on the surface after anodic oxidation makes the titanium alloy have a certain antibacterial effect on Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli). This research could set the groundwork for the study of micro-manufacturing technology and pave the way for future implant surface design.

Synthesis of Chitosan-Silver Nanocomposite and Its Evaluation as an Antibacterial Coating for Mobile Phone Glass Protectors.

An easy and environment-friendly route for antibacterial coating suited for mobile phone glass protectors was successfully demonstrated. In this route, freshly prepared chitosan solution in 1% v/v acetic acid was added with 0.1 M silver nitrate solution and 0.1 M sodium hydroxide solution and incubated with agitation at 70 °C to form chitosan-silver nanoparticles (ChAgNPs). Varied concentrations of chitosan solution (i.e., 0.1, 0.2, 0.4, 0.6, and 0.8% w/v) were used to investigate its particle size, size distribution, and later on, its antibacterial activity. Transmission electron microscope (TEM) imaging revealed that the smallest average diameter of silver nanoparticles (AgNPs) was 13.04 nm from 0.8% w/v chitosan solution. Further characterizations of the optimal nanocomposite formulation using UV-vis spectroscopy and Fourier transfer infrared spectroscopy were also performed. Using a dynamic light scattering zetasizer, the average ζ-potential of the optimal ChAgNP formulation was at +56.07 mV, showing high aggregative stability and an average ChAgNP size of 182.37 nm. The ChAgNP nanocoating on glass protectors shows antibacterial activity against Escherichia coli (E. coli) at 24 and 48 h of contact. However, the antibacterial activity decreased from 49.80% (24 h) to 32.60% (48 h).

Electrophoretic Deposition, Microstructure, and Selected Properties of Poly(lactic-co-glycolic) Acid-Based Antibacterial Coatings on Mg Substrate.

There is an urgent need to develop biodegradable implants that can degrade once they have fulfilled their function. Commercially pure magnesium (Mg) and its alloys have the potential to surpass traditional orthopedic implants due to their good biocompatibility and mechanical properties, and most critically, biodegradability. The present work focuses on the synthesis and characterization (microstructural, antibacterial, surface, and biological properties) of poly(lactic-co-glycolic) acid (PLGA)/henna (Lawsonia inermis)/Cu-doped mesoporous bioactive glass nanoparticles (Cu-MBGNs) composite coatings deposited via electrophoretic deposition (EPD) on Mg substrates. PLGA/henna/Cu-MBGNs composite coatings were robustly deposited on Mg substrates using EPD, and their adhesive strength, bioactivity, antibacterial activity, corrosion resistance, and biodegradability were thoroughly investigated. Scanning electron microscopy and Fourier transform infrared spectroscopy studies confirmed the uniformity of the coatings' morphology and the presence of functional groups that were attributable to PLGA, henna, and Cu-MBGNs, respectively. The composites exhibited good hydrophilicity with an average roughness of 2.6 μm, indicating desirable properties for bone forming cell attachment, proliferation, and growth. Crosshatch and bend tests confirmed that the adhesion of the coatings to Mg substrates and their deformability were adequate. Electrochemical Tafel polarization tests revealed that the composite coating adjusted the degradation rate of Mg substrate in a human physiological environment. Incorporating henna into PLGA/Cu-MBGNs composite coatings resulted in antibacterial activity against Escherichia coli and Staphylococcus aureus. The coatings stimulated the proliferation and growth of osteosarcoma MG-63 cells during the initial incubation period of 48 h (determined by the WST-8 assay).

Smart multifunctional coatings for antibacterial and self-cleaning applications

The contamination of healthcare and industrial surfaces by microbes, particularly antibiotic-resistant strains, has stimulated more excellent studies into creating effective antibacterial coatings. This work presents the rapid synthesis of metal nitrate (Ag) doped methyltrimethoxysilane (MTMS) coatings and the quick assessment of their antibacterial activity. The coatings were challenged with Gram-positive and Gram-negative bacterial cultures. The surface roughness of the modified coatings increases from 23.15 nm to 51.17 nm, and the corresponding water contact angle increases from 97° to 154°. Electron micrographs of the Ag/SiO2 coatings revealed a highly porous network of silica particles on the glass surface. The Ag/SiO2 coatings showed moderate antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus) whereas strong antibacterial properties against Gram-negative bacteria (Escherichia coli).

In Vitro and In Vivo Studies of Antibacterial Coatings on Titanium Alloy Implants for Veterinary Application.

The aim of this work was the evaluation of biological properties of hybrid coatings modified with Ag, Cu, and Zn nanoparticles (NPs) applied on TPLO medical implants by the sol-gel process. The implant coatings enriched with various concentrations of metallic NPs were investigated in the in vitro bactericidal efficacy tests against Gram+ and Gram- bacteria and pathogenic yeast. Next, the designed materials were tested on human osteosarcoma cell lines. The cells adhesion, proliferation, viability, and differentiation were investigated. The cell growth wasevaluated using SEM, and the metallic ion release was measured. The results revealed that the NPs concentration in the hybrid layers decreased with the incubation time. In the last stage, the implants were tested in vivo on six canine patients. Three months after the operation, the radiological evaluation of the performed anastomosis was carried out as well as the histopathological evaluation of tissue regeneration. The strongest bactericidal efficacy was observed for the layers containing AgNPs. Along with an increased concentration of metallic additives, a growing toxic effect was clearly observed. The most pronounced toxic effect was especially evident with the AgNPs concentration exceeding 1 mol %. In all the operated patients, no deviations were found during the follow-up examinations in the postoperative period. The low dose of AgNPs in the hybrid layer facilitated the tissue healing process. It was proven that silver nanoparticles may accelerate the bone healing process. The correct tissue reparation was observed.

Ion-Doped Calcium Phosphate-Based Coatings with Antibacterial Properties.

Ion-substituted calcium phosphate (CP) coatings have been extensively studied as promising materials for biomedical implants due to their ability to enhance biocompatibility, osteoconductivity, and bone formation. This systematic review aims to provide a comprehensive analysis of the current state of the art in ion-doped CP-based coatings for orthopaedic and dental implant applications. Specifically, this review evaluates the effects of ion addition on the physicochemical, mechanical, and biological properties of CP coatings. The review also identifies the contribution and additional effects (in a separate or a synergistic way) of different components used together with ion-doped CP for advanced composite coatings. In the final part, the effects of antibacterial coatings on specific bacteria strains are reported. The present review could be of interest to researchers, clinicians, and industry professionals involved in the development and application of CP coatings for orthopaedic and dental implants.

Tetrapodal ZnO nanomaterial synthesis for antibacterial fluoroethylene vinyl ether polymer coating

Antibacterial coatings can be nanofabricated to provide antimicrobial persistence, nanostructural tailoring, and superhydrophobicity. This study presents a method for preparing an effective antibacterial coating by introducing tetrapodal ZnO (T-ZnO) nanomaterials on a fluoroethylene vinyl ether polymer (FEVE). T-ZnO nanomaterials were as-synthesized by flame transport synthesis and characterized. The T-ZnO exhibited a tetrapodal micro- and nanostructure with four legs of ∼43 μm diameter, comprising 86.67 and 12.90 wt% of Zn and O, respectively. High-resolution images of a single leg with sharp whiskers exhibited well-developed crystallinity. The antibacterial capabilities of T-ZnO functional coatings were determined using a reaction solution consisting of FEVE directly soaked in various wt% of T-ZnO with ethyl acetate. The 10 wt% T-ZnO nanocomplex coating exhibited the best surface hydrophobicity, with a water contact angle of 155°. The proposed T-ZnO on a fluoroethylene polymer-based coating exhibited higher antibacterial efficacy toward Gram-positive S. Aureus and -negative E. Coli compared with a standard polymer-based coating. In examining cellular toxicity, no harm was found to NIH/3T3 cells using the CCK-8 assay. Hence, this study provides a simple method for preparing safe and effective antibacterial coatings for practical applications.

Antibacterial-Based Hydrogel Coatings and Their Application in the Biomedical Field—A Review

Hydrogels exhibit excellent moldability, biodegradability, biocompatibility, and extracellular matrix-like properties, which make them widely used in biomedical fields. Because of their unique three-dimensional crosslinked hydrophilic networks, hydrogels can encapsulate various materials, such as small molecules, polymers, and particles; this has become a hot research topic in the antibacterial field. The surface modification of biomaterials by using antibacterial hydrogels as coatings contributes to the biomaterial activity and offers wide prospects for development. A variety of surface chemical strategies have been developed to bind hydrogels to the substrate surface stably. We first introduce the preparation method for antibacterial coatings in this review, which includes surface-initiated graft crosslinking polymerization, anchoring the hydrogel coating to the substrate surface, and the LbL self-assembly technique to coat crosslinked hydrogels. Then, we summarize the applications of hydrogel coating in the biomedical antibacterial field. Hydrogel itself has certain antibacterial properties, but the antibacterial effect is not sufficient. In recent research, in order to optimize its antibacterial performance, the following three antibacterial strategies are mainly adopted: bacterial repellent and inhibition, contact surface killing of bacteria, and release of antibacterial agents. We systematically introduce the antibacterial mechanism of each strategy. The review aims to provide reference for the further development and application of hydrogel coatings.

Construction of ZnO/PCL Antibacterial Coating Potentially for Dental Unit Waterlines

The formation of bacterial biofilms and the contamination of treatment water within dental unit waterlines can lead to a risk of secondary bacterial infections in immunocompromised patients. Although chemical disinfectants can reduce the contamination of treatment water, they can also cause corrosion damage to dental unit waterlines. Considering the antibacterial effect of ZnO, a ZnO-containing coating was prepared on the surface of polyurethane waterlines using polycaprolactone (PCL) with a good film-forming capacity. The ZnO-containing PCL coating improved the hydrophobicity of polyurethane waterlines, thus inhibiting the adhesion of bacteria. Moreover, the continuous slow release of Zn ions endowed polyurethane waterlines with antibacterial activity, thus effectively preventing the formation of bacterial biofilms. Meanwhile, the ZnO-containing PCL coating had good biocompatibility. The present study suggests that ZnO-containing PCL coating can realize a long-term antibacterial effect on the polyurethane waterlines by itself, providing a novel strategy for the manufacture of autonomous antibacterial dental unit waterlines.

Hydroxyapatite/poly(vinyl alcohol)/chitosan coating with gentamicin for orthopedic implants

Electrophoretic deposition (EPD) was employed to fabricate composite coatings aimed for orthopedic implants. Hydroxyapatite (HAP), poly(vinyl alcohol) (PVA) and chitosan (CS) coatings, with or without antibiotic gentamicin (Gent) were deposited in a single-step process from aqueous suspension, using EPD. Polymer/mineral composite coatings were formed with the aim to mimic the natural composition of bone tissue, along with improved coatings antibacterial properties, at the same time serving as a drug carrier, allowing local administration of antibiotic. Structural and morphological characterization of HAP/PVA/CS and HAP/PVA/CS/Gent coatings was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), and scanning electron microscopy (SEM) proving carbonate-substituted HAP. The presence of gentamicin contributed to the bactericidal activity of composite HAP/PVA/CS/Gent coating against Staphylococcus aureus and Escherichia coli. Cytotoxicity studies were performed towards human MRC-5 and mice L929 fibroblast cell lines, and both investigated samples (HAP/PVA/CS and HAP/PVA/CS/Gent) expressed good biocompatibility, without causing toxic effect on tested cells. Biomineralization potential was investigated by measuring the alkaline phosphatase activity, demonstrating high potential of HAP/PVA/CS/Gent to induce the growth of new HAP layer. Therefore, the present investigation proposes the production of composite coatings from non-toxic (aqueous) suspensions, consisting of biocompatible and bioactive components, along with antibiotic gentamicin, improving the antibacterial coatings' properties.

Multifunctional cotton fabrics with novel antibacterial coatings based on chitosan nanocapsules and polyacrylate.

The online version contains supplementary material available at 10.1007/s11998-023-00761-y.