Antibacterial Coatings Research Articles

Silver-Treated Silk Fibroin Scaffolds for Prevention of Critical Wound Infections

The risk of infections in chronic wounds represents a serious issue, particularly in aged people and in patients affected by diseases such as diabetes and obesity. Moreover, the growing resistance demonstrated by many bacterial strains has significantly reduced the therapeutic options for clinicians and has become a great challenge for the researchers in the definition of novel approaches that promote the wound healing process and reduce the healing time. Tissue engineering approaches based on biomaterials and three-dimensional scaffolds have demonstrated huge potential in supporting cell proliferation; among them, Bombyx mori-derived silk fibroin is a very appealing possibility for the development of devices with regenerative properties for wound healing applications. However, due to the high risk of infections in chronic wounds, an antibacterial treatment is also strongly encouraged for preventing bacterial proliferation at the wound site. In this work, to develop a device with regenerative and antibacterial properties, antibacterial silver coatings were deposited onto silk fibroin scaffolds, and the effect of the treatment in terms of chemical–physical and microbiological properties was investigated. The results demonstrated that the silver treatment improved the mechanical properties of the protein scaffold and provided good antibacterial efficacy against representative bacterial strains in wound infection, namely Escherichia coli and antibiotic-resistant Pseudomonas aeruginosa.

The effect of coating chitosan from cuttlefish bone (Sepia Sp.) on the surface of orthodontic mini-screw

IntroductionPeri-implantitis is a significant complication resulting from the failure of orthodontic mini-screws. Recent strategies to address this issue include the application of natural antibacterial coatings to prevent bacterial colonization. Notably, cuttlefish (Sepia sp.) bones are rich in chitosan, which is recognized for its antibacterial effectiveness and biocompatibility. ObjectivesTo evaluate the effects of a chitosan coating derived from cuttlefish bone (Sepia sp.) on mini-screws against Aggregatibacter actinomycetemcomitans bacteria frequently linked to peri‑implantitis. Materials and MethodsThe surface functional groups, phase composition, and crystal morphology of chitosan were analyzed using conventional analytic techniques alongside energy-dispersive X-ray analysis. These prepared were tested for antibacterial activity against A. actinomycetemcomitans by disk diffusion assay; minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) were determined. Stainless steel mini-screws were coated with chitosan, and their surfaces were characterized using scanning electron microscopy (SEM). ResultsThe investigation revealed that chitosan exhibited a MIC value of 8 ppm against A. actinomycetemcomitans with MBCs recorded at 16 ppm. Zones of inhibition varied based on concentration; notably, concentrations at 0.4 %, 0.6 %, and 0.8 % produced zones averaging 16.17 ± 1.64 mm collectively while increasing to a mean zone size of 20.99 ± 3.63 mm at the highest tested concentration (0.8 %). SEM analyses further confirmed the successful adhesion of the chitosan compound onto immersed mini-screw surfaces. ConclusionThe prepared chitosan from cuttlefish bone (Sepia sp.) has antibacterial activity against the bacteria A. actinomycetemcomitans in vitro and can successfully coat SS mini-screws to enhance their efficiency.

Bacterial Binding to Polydopamine-Coated Magnetic Nanoparticles.

In medical infections such as blood sepsis and in food quality control, fast and accurate bacteria analysis is required. Using magnetic nanoparticles (MNPs) for bacterial capture and concentration is very promising for rapid analysis. When MNPs are functionalized with the proper surface chemistry, they have the ability to bind to bacteria and aid in the removal and concentration of bacteria from a sample for further analysis. This study introduces a novel approach for bacterial concentration using polydopamine (pDA), a highly adhesive polymer often purported to create antibacterial and antibiofouling coatings on medical devices. Although pDA has been generally studied for its ability to coat surfaces and reduce biofilm growth, we have found that when coated on magnetic nanoclusters (MNCs), more specifically iron oxide nanoclusters, it effectively binds to and can remove from suspension some types of bacteria. This study investigated the binding of pDA-coated MNCs (pDA-MNCs) to various Gram-negative and Gram-positive bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and several E. coli strains. MNCs were successfully coated with pDA, and these functionalized MNCs bound a wide variety of bacterial strains. The efficiency of removing bacteria from a suspension can range from 0.99 for S. aureus to 0.01 for an E. coli strain. Such strong capture and differential capture have important applications in collecting bacteria from dilute samples found in medical diagnostics, food and water quality monitoring, and other industries.

Machine Learning Aided Design and Optimization of Antifouling Surfaces.

Antifouling surfaces, renowned for their strong surface resistance to proteins, cells, or tissues in various biological and environmental conditions, have broad applications in implanted devices, antibacterial coatings, biosensors, responsive materials, water treatment, and lab-on-a-chip. While extensive experimental research exists on antifouling surfaces, machine learning studies on this topic are relatively few. This perspective specifically focuses on exploring the complex relationships between the composition, structure, and properties of antifouling surfaces, examining how these factors correlate with surface hydration and protein adsorption. Different machine learning models have been developed to analyze and predict single and multiple protein adsorptions on various types of surfaces, ranging from structureless surfaces to well-ordered and rigid self-assembled monolayers, dynamically ordered polymer brushes, and complex filtration membranes. These models not only identify key descriptors or functional groups critical for antifouling performance (surface hydration, protein adsorption) but also predict the antifouling properties for a specific surface. Recognizing current challenges, this perspective delineates future research directions in the antifouling field. By leveraging and comparing current machine learning approaches, it aims to advance both the design and fundamental understanding of antifouling surfaces, thereby pushing the boundaries of innovation in this critical field.

Tripartite synergy: Photodegradation of congo red and bromothymol blue with concurrent bacterial photoinhibition using ZnCe/Bi2Mn2O6/rGO nanocomposites

The present research studies show the multidimensional characteristics of ZnCe/Bi2Mn2O6/rGO nanostructures for photocatalytic degradation of bromothymol blue (BTB), Congo red (CR) and photoinhibition of E. coli and S. aureus. A new solvothermal protocol was applied for the synthesis of ZnCe/Bi2Mn2O6/rGO nanomaterial. Important analytical techniques were applied for the characterization of the said nanomaterials. When allowed to visible light, the said nanostructure demonstrated excellent photocatalytic degradation of both the said dyes. The findings revealed that almost 99 % of both dyes were eliminated in just 30 min. In the absence of light, there was less than 60 % decline in both dyes even after 100 min. The ZnCe/Bi2Mn2O6/rGO was tested multiple times against the said dyes, and after seven cycles, its efficiency was reduced by only 15 %. Moreover, the nanostructures exhibited promising antibacterial properties by inducing photoinhibition of both E. coli and S. aureus bacteria. The inhibition zones of ZnCe/Bi2Mn2O6/rGO under visible light irradiation were measured to be approximately 17 ± 0.2 mm against E. coli and 19 ± 0.3 mm against S. aureus. These nanostructures effectively impeded bacterial growth and viability, underscoring their potential for applications in water disinfection and as antibacterial coatings. They are promising options for a variety of applications, especially as catalysts in many industries, due to their non-toxic nature and thermal stability. This work presents fascinating avenues for further investigation into the application of nanocomposites in healthcare and environmental preservation.

Electrostatic Spraying of Zinc Carbonate Hydroxide-Infused Ethylene-tetrafluoroethylene Powders: A Thermally-Induced, VOC-Free Antibacterial Superhydrophobic Coating

This study introduces an environmentally friendly method to create a superhydrophobic antibacterial coating using electrostatic powder spraying. The process utilizes ethylene-tetrafluoroethylene copolymer (ETFE) and zinc carbonate hydroxide (ZCH) powders and no organic solvent was used. The resulting coating takes advantage of ETFE's hydrophobic properties and the microstructure generated from ZCH's thermal decomposition, producing a micrometer-scale porous structure with a water contact angle of 165°. It demonstrates strong adhesion to substrates, fulfilling grade 0 standards as per GB/T 9286-2021 / ISO 2409:2020. Following 3 cycles of the falling-sand test, as outlined by ISO/TS 10689:2023, the contact angle impressively remains above 150°, underscoring its extraordinary resistance in contrast to coatings described in literature that typically endure just about 1 cycle. Even after 10 cycles of high-speed water jet impacts following ISO/TS 10689:2023, it maintains a water contact angle of 145°, equivalent to resisting ten years of continuous rainfall based on ISO/TS 10689:2023. The coating's antibacterial effectiveness, stemming from its superhydrophobic characteristics and the antibacterial properties of ZnO produced by ZCH decomposition, achieves inhibition rates of 99.6% and 99.8% against E. coli (ATCC 25922) and S. aureus (ATCC 6538) respectively, highlighting its significant potential for practical applications.

Innovative pH-triggered antibacterial nanofibrous coatings for enhanced metallic implant properties

Metallic stainless steel bone implants are widely used due to their excellent mechanical properties, low cost, and ease of fabrication. Nanofibrous composite polymers have been proposed as coatings to promote biocompatibility and osseointegration, thanks to their biomimetic morphology that resembles the extracellular matrix. However, critical practical issues are often overlooked in the literature. For instance, applying coatings to implants with different shapes presents a significant technological challenge, as does evaluating viable sterilization procedures for hybrid devices containing electrospun polymers. In addition, infections pose a risk in any surgical procedure and can lead to implant failure, there is a need for antimicrobial prevention during surgery as well as in the short term afterward. In this work, we propose a new and straightforward method for manufacturing nanofibrous composite coatings directly on thin cylindrical-shaped metallic implants. Poly(ε-caprolactone) (PCL) nanofibers containing bioactive glass microparticles were electrospun onto stainless steel wires and then post-treated using two different strategies to achieve both hydrophilicity and surface disinfection. To address antimicrobial properties, amoxicillin-loaded Eudragit®E nanofibers were co-electrospun to impart pH-selective release behavior in event of a potential infection. The resulting composite hybrid coatings were characterized morphologically, physically, chemically, and electrochemically. The antibacterial behavior was evaluated at different media, confirming the release of the antibiotic in the pH range where infection is likely to occur. The impact of this study lies in its potential to significantly enhance the safety and efficacy of orthopedic implants by offering a novel, adaptable solution to combat infection. By integrating a pH-responsive drug delivery system with antimicrobial coatings, this approach not only provides a preventive measure during and after surgery but also addresses the growing issue of antibiotic resistance by targeting specific infection conditions.

Antibacterial cationic porous organic polymer coatings via an adsorption-contact-photodynamic inactivation strategy for treatment of drug-resistant bacteria

Although photodynamic therapy (PDT) has great potential for treating severely infected wounds, it is restricted by the short lifetime, limited diffusion distance of reactive oxygen species (ROS), and incomplete contact with bacteria. Herein, we report a novel nanosized ionic porous organic polymer (TPAPy-IPOP) based on the triphenylamine (TPA) moiety. Strong electron-deficient cationic groups were introduced into TPA to construct the donor–acceptor (D–A) system, in which the photoelectric effect of TPAPy-IPOP was greatly enhanced, and it was easily excited to produce ROS under irradiation with visible light. The introduction of cations not only facilitated bacterial adsorption by TPAPy-IPOP via electrostatic attraction, which was more conducive to killing bacteria by ROS, but also inactivated bacteria by the cations directly. The nanosized TPAPy-IPOP remained suspended in water for several months and could be sprayed onto various substrates to form a durable coating with excellent antibacterial properties. The in vivo results proved that the silk fibroin/polyvinyl alcohol non-woven fabric (SF/PVA) coated with TPAPy-IPOP could create and maintain a sterile microenvironment at a wound site. The rapid reduction in inflammation resulting from its bactericidal action accelerated the wound healing rate. Collectively, this design is expected to offer a generalizable approach for developing novel antibacterial therapeutic photosensitizers, especially for infected wound treatment.

Long-Lasting, Transparent Antibacterial Shield: A Durable, Broad-Spectrum Anti-Bacterial, Non-Cytotoxic, Transparent Nanocoating for Extended Wear Contact Lenses.

The increasing incidence of serious bacterial keratitis, a sight-threatening condition often exacerbated by inadequate contact lens (CLs) care, highlights the need for innovative protective technology. This study introduces a long-lasting antibacterial, non-cytotoxic, transparent nanocoating for CLs via a solvent-free polymer deposition method, aiming to prevent bacterial keratitis. The nanocoating comprises stacked polymer films, with poly(dimethylaminomethyl styrene-co-ethylene glycol dimethacrylate) (pDE) as a biocompatible, antibacterial layer atop poly(2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane) (pV4D4) as an adhesion-promoting layer. The pD6E1-grafted (g)-pV4D4 film shows non-cytotoxicity toward two human cell lines and antibacterial activity of >99% against four bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), an antibiotic-resistant bacteria and Pseudomonas aeruginosa, which causes ocular diseases. Additionally, the film demonstrates long-lasting antibacterial activity greater than 96% against MRSA for 9 weeks in phosphate-buffered saline. To the best knowledge, this duration represents the longest reported long-term stability with less than 5% decay of antibacterial performance among contact-killing antibacterial coatings. The film exhibits exceptional mechanical durability, retaining its antibacterial activity even after 15 washing cycles. The pD6E1-g-pV4D4-coated CL maintains full optical transmittance compared to that of pristine CL. It is expected that the unprecedentedly prolonged antibacterial performance of the coating will significantly alleviate the risk of infection for long-term CL users.

Advanced catalytic and biomedical applications of silver functionalized SnCuO3 nanocomposites synthesized through novel surfactant mediated chemical approach

In the current contribution, silver impregnated and un impregnated bimetallic oxide nanocomposites of SnCuO3 were synthesized by a novel surfactant mediated chemical approach. The tween-80 was used as a surfactant to effectively modulate the morphological features of the nanocomposites. The synthesized nanocomposites were characterized by XRD, HRTEM, SEM, EDX, FTIR and XPS. The results revealed the rod-shaped surface morphology of the nanocomposites with length and diameter of 245 nm and 66 nm respectively. The synthesized nanocomposites were tested for catalytic and biomedical applications. The rate of catalytic degradation reaction of methylene blue by the SnCuO3 and Ag/SnCuO3 nanocomposites were found to be 10.2 and 8.5 respectively. Only in 10 min all the dye molecules were degraded. The synthesized nanomaterials SnCuO3 and Ag/SnCuO3 are potent antileishmanial agents having CC50 value 12728.03 and 3001.70 µg/mL respectively that were found to be biocompatible with very low toxicity as revealed by their hemolytic activity results. Moreover, the nanostructures exhibited promising antibacterial properties by effectively inhibiting the growth of both E. coli and S. aureus bacteria through photoinhibition. When subjected to visible light irradiation, the growth inhibition zone of Ag/SnCuO3 against E. coli and S. aureus was measured at (15 ± 0.4 mm) and (17 ± 0.3 mm), respectively. These nanostructures demonstrated the ability to impede bacterial proliferation and viability, underscoring their potential for use in water disinfection and as antibacterial coatings utilizing Ag/SnCuO3.

Smart Antibacterial Coatings with On‐Demand Drug Release and Real‐Time Monitoring

AbstractSmart antibacterial coatings with surface‐independent methods, on‐demand antibiotic release, and real‐time drug loading monitoring capabilities have attracted increasing interest in the fields of medical devices, antibiotics delivery platforms, and implantable devices. Addressing the complexity inherent in existing methods, this work innovates by simplifying the synthesis process and integrating aminoglycosides with metallosupramolecules to develop versatile and effective coatings. These coatings not only exhibit exceptional biological activity and efficient antibacterial properties both in vitro and in vivo, but also enable high drug loading and controlled release. Significantly, their application across various devices has demonstrated profound therapeutic effects in treating implant infections and promoting bacterial wound healing. A key advancement of these coatings is the integration of color‐changing indicators for real‐time monitoring of drug levels, enhancing the precision of wound care, and facilitating timely clinical interventions. This research marks a significant stride in the development of more accessible, bioactive, and smart antibacterial materials, opening new avenues in the field of smart medical coatings.

Innovative Ag@Cu/white sand and polysaccharide based nanocomposites: A simple route to conductive and antibacterial paper coatings

In this work, we presented a simple method for preparing nanocomposite pigments via doping the naturally occurring white sand pigment using silver (Ag) and copper (Cu). The nanocomposites (Ag@WS, Cu@WS, and Ag&Cu@WS) were produced in two suspensions at 25 % and 50 % w/v concentrations, utilizing casein (Cas) and nanostarch (NanoSt) as bio-friendly binders. The prepared nanocomposite pigments were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction crystallography (XRD), and dynamic light scattering (DLS), as well as topographical analysis including scanning electron microscopy (SEM), EDX, and transmission electron microscopy (TEM). The coated paper sheets were characterized using topographical analysis and mechanical, optical, physical, and electrical properties. The antimicrobial activity assay was carried out on the coated paper sheets using the most infectious microbial pathogens. FTIR and XRD analyses confirmed the presence of Cas and NanoSt in the samples. The addition of white sand (WS) and doped nano-metals influenced the crystallographic structure of the polysaccharides. A small amount of Ag, Cu, and Ag&Cu nanoparticles was investigated through EDX. The white sand was a plate structure decorated with spherical Ag, Cu, and Ag&Cu nanoparticles, with an average size of about 147, 105, and 78 nm, as observed from TEM images and DLS. The antimicrobial activity assays revealed that nanocomposite pigment embedded with bimetallic Ag&Cu nanoparticles exhibited a synergistic effect, resulting in enhanced broad-spectrum antibacterial and antifungal activities. The electrical performance of the coated paper was enhanced by using Ag&Cu@WS nanocomposite pigment. Incorporating 50 % Cu@WS into the coating resulted in significant improvements in the mechanical properties of the paper. Specifically, tensile strength increased by 6.3 N/mm, tensile index by 69.06 N m/g, stretching by 1.68 %, tensile energy absorption by 71.4 J/m2, burst strength by 257.75 kPa, and burst index by 2.83 kPa m2/g. Furthermore, incorporating 50 % Ag&Cu@WS increased the opacity to 93.2 % and reduced the roughness of the coated paper by 36 % compared to using 50 % Ag@WS or 50 % Cu@WS alone.

A Review of the Development of Titanium-Based and Magnesium-Based Metallic Glasses in the Field of Biomedical Materials.

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young's modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young's modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes.

3D-printed porous titanium rods equipped with vancomycin-loaded hydrogels and polycaprolactone membranes for intelligent antibacterial drug release

Implant-related infections pose significant challenges to orthopedic surgeries due to the high risk of severe complications. The widespread use of bioactive prostheses in joint replacements, featuring roughened surfaces and tight integration with the bone marrow cavity, has facilitated bacterial proliferation and complicated treatment. Developing antibacterial coatings for orthopedic implants has been a key research focus in recent years to address this critical issue. Researchers have designed coatings using various materials and antibacterial strategies. In this study, we fabricated 3D-printed porous titanium rods, incorporated vancomycin-loaded mPEG750-b-PCL2500 gel, and coated them with a PCL layer. We then evaluated the antibacterial efficacy through both in vitro and in vivo experiments. Our coating passively inhibits bacterial biofilm formation and actively controls antibiotic release in response to bacterial growth, providing a practical solution for proactive and sustained infection control. This study utilized 3D printing technology to produce porous titanium rod implants simulating bioactive joint prostheses. The porous structure of the titanium rods was used to load a thermoresponsive gel, mPEG750-b-PCL2500 (PEG: polyethylene glycol; PCL: polycaprolactone), serving as a novel drug delivery system carrying vancomycin for controlled antibiotic release. The assembly was then covered with a PCL membrane that inhibits bacterial biofilm formation early in infection and degrades when exposed to lipase solutions, mimicking enzymatic activity during bacterial infections. This setup provides infection-responsive protection and promotes drug release. We investigated the coating’s controlled release, antibacterial capability, and biocompatibility through in vitro experiments. We established a Staphylococcus aureus infection model in rabbits, implanting titanium rods in the femoral medullary cavity. We evaluated the efficacy and safety of the composite coating in preventing implant-related infections using imaging, hematology, and pathology. In vitro experiments demonstrated that the PCL membrane stably protects encapsulated vancomycin during PBS immersion. The PCL membrane rapidly degraded at a lipase concentration of 0.2 mg/mL. The mPEG750-b-PCL2500 gel ensured stable and sustained vancomycin release, inhibiting bacterial growth. We investigated the antibacterial effect of the 3D-printed titanium material, coated with PCL and loaded with mPEG750-b-PCL2500 hydrogel, using a rabbit Staphylococcus aureus infection model. Imaging, hematology, and histopathology confirmed that our composite antibacterial coating exhibited excellent antibacterial effects and infection prevention, with good safety in trials. Our results indicate that the composite antibacterial coating effectively protects vancomycin in the hydrogel from premature release in the absence of bacterial infection. The outer PCL membrane inhibits bacterial growth and prevents biofilm formation. Upon contact with bacterial lipase, the PCL membrane rapidly degrades, releasing vancomycin for antibacterial action. The mPEG750-b-PCL2500 gel provides stable and sustained vancomycin release, prolonging its antibacterial effects. Our composite antibacterial coating demonstrates promising potential for clinical application.

As-deposited and dewetted Cu layers on plasma treated glass: Adhesion study and its effect on biological response

Improving the adhesion of nanosized copper films to a glass substrate is vital for their application in electronics and medicine, as it enhances their overall reliability. For this purpose, we employed Ar plasma etching (240 s) and magnetron sputtering to create copper layers on a glass substrate. Furthermore, we investigated the effect of subsequent solid state dewetting (at 300 °C) of Cu nanolayers on the interface stability. Increasing the sputtering time resulted in elevated copper concentration, UV-Vis absorption, conductivity, and surface roughness. The as-deposited and dewetted samples exhibited very good wettability with water contact angles below 60°. Importantly, plasma treatment improved the adhesion of the Cu layers to the glass. Subsequent dewetting accelerated surface diffusion and the oxidation of Cu atoms, causing structural and morphological changes. The presence of CuO after dewetting caused loss of the surface plasmon resonance (SPR) band in the UV-Vis spectrum and a decrease in sample conductivity due to the transformation of the copper layer from a metal to an oxide. Biological testing revealed a more pronounced bactericidal effect for the as-deposited Cu layer against E. coli and S. epidermidis on contrary to dewetted samples. The similar cytotoxic trend was observed for human dermal fibroblasts and hepatocytes. Nonetheless, biological testing confirmed better cell adhesion on dewetted Cu layers compared to the as-deposited ones. Therefore, our copper nanostructured samples could find application as antibacterial coatings of biomedical devices.

Screening of Lithium Substituted Ag-TiO2 Nanoparticle Coating for Antibiofilm Application.

Bacterial infections and biofilm growth are common mishaps associated with medical devices, and they contribute significantly to ill health and mortality. Removal of bacterial deposition from these devices is a major challenge, resulting in an immediate necessity for developing antibacterial coatings on the surfaces of medical implants. In this context, we developed an innovative coating strategy that can operate at low temperatures (80 °C) and preserve the devices' integrity and functionality. An innovative Ag-TiO2 based coating was developed by ion exchange between silver nitrate (AgNO3) and lithium titanate (Li4Ti5O12) on glass substrates for different periods, ranging from 10 to 60 min. The differently coated samples were tested for their antibacterial and antibiofilm efficacy.

Antibacterial mechanism of water-soluble CeO2 nanoflowers and its product design in antibacterial application

Antibacterial surface coatings have attracted growing attention in the textile industry. In this study, water-soluble CeO2 nanoflowers were synthesized by a modified critical micelle antisolvent method, displaying the potential for mass production at a low cost. The structure and electronic states of CeO2 were investigated deeply. Moreover, the antibacterial mechanism of CeO2 was studied in depth. The results revealed that CeO2 nanoflowers with abundant oxygen vacancies can adsorb O2 and produce amounts of reactive oxygen species (ROS) by the electron transfer of Ce4+ and Ce3+. These compounds can destroy cell walls, resulting in the leakage of bacterial nucleic acids and proteins, leading to bacterial death. The CeO2 nanoflowers exhibited broad-spectrum antimicrobial properties and biological safety. The antibacterial cotton fabric was prepared by the impregnation method. Considering the material impregnation amounts and impregnation time, a new washing machine was designed to prepare the antibacterial fabric. In this work, fabrics were modified using CeO2 nanoflowers with a simple method suitable for mass production, showing great application potential in antimicrobial cotton fabric. In addition, in order to further expand the application field of CeO2 nanoflowers, antibacterial elevator button patches, antibacterial coatings and other products were designed.

Expanding Our Horizons: AIE Materials in Bacterial Research.

Bacteria share a longstanding and complex relationship with humans, playing a role in protecting gut health and sustaining the ecosystem to cause infectious diseases and antibiotic resistance. Luminogenic materials that share aggregation-induced emission (AIE) characteristics have emerged as a versatile toolbox for bacterial studies through fluorescence visualization. Numerous research efforts highlight the superiority of AIE materials in this field. Recent advances in AIE materials in bacterial studies are categorized into four areas: understanding bacterial interactions, antibacterial strategies, diverse applications, and synergistic applications with bacteria. Initial research focuses on visualizing the unseen bacteria and progresses into developing strategies involving electrostatic interactions, amphiphilic AIE luminogens (AIEgens), and various AIE materials to enhance bacterial affinity. Recent progress in antibacterial strategies includes using photodynamic and photothermal therapies, bacterial toxicity studies, and combined therapies. Diverse applications from environmental disinfection to disease treatment, utilizing AIE materials in antibacterial coatings, bacterial sensors, wound healing materials, etc., are also provided. Finally, synergistic applications combining AIE materials with bacteria to achieve enhanced outcomes are explored. This review summarizes the developmental trend of AIE materials in bacterial studies and is expected to provide future research directions in advancing bacterial methodologies.

A Facile and Green Approach for the Preparation of Silver Nanoparticles on Graphene Oxide with Favorable Antibacterial Activity.

Herein, we introduce a simple precipitation method for preparing graphene oxide-silver nanoparticle (GO/AgNP) composites, utilizing Calendula officinalis (C. officinalis) seed extract as both a reducing and stabilizing agent. Our research combines the sustainable preparation of graphene oxide (GO) with the green synthesis of silver nanoparticles (AgNPs), aiming to explore the potential of the obtained composite as a novel antibacterial material. To establish a benchmark, the synthesis was also performed using sodium citrate, a conventional reducing agent. The resultant GO/AgNP composites were characterized through several analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD), infrared (IR) spectroscopy, and ultraviolet-visible (UV-vis) spectroscopy, confirming the successful functionalization of GO with AgNPs. The antibacterial effectiveness of the composites was systematically assessed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with nanoparticle concentrations spanning from 0 to 250 µg/mL, utilizing mostly disk diffusion and colony-forming unit (CFU) count assays. The AgNPs were characterized by a size range of 15-50 nm. Notably, the GO/AgNP composite prepared using C. officinalis seed extract demonstrated superior antibacterial activity at all tested concentrations, outperforming both pure GO and the GO/AgNP composite prepared with sodium citrate. The most pronounced antibacterial effect was observed at a concentration of 32.0 µg/mL. Therefore, this innovative synthesis approach may offer a valuable contribution to the development of new therapeutic agents to combat bacterial infections, suggesting further exploration into antibacterial coatings or potential drug development.

Antibacterial and Anticorrosive Hydrogel Coating Based on Complementary Functions of Sodium Alginate and g-C3N4.

Graphitic carbon nitride (g-C3N4, CN) has emerged as a promising photocatalytic material due to its inherent stability, antibacterial properties, and eco-friendliness. However, its tendency to aggregate and limited dispersion hinder its efficacy in practical antibacterial applications. To address these limitations, this study focuses on developing a composite hydrogel coating, in which sodium alginate (SA) molecules interact electrostatically and through hydrogen bonding to anchor CN, thereby significantly improving its dispersion. The optimal CN loading of 35% results in a hydrogel with a tensile strength of 120 MPa and an antibacterial rate of 99.87% within 6 h. The enhanced mechanical properties are attributed to hydrogen bonding between the -NH2 groups of CN and the -OH groups of SA, while the -OH groups of SA facilitate the attraction of photogenerated holes from CN, promoting carrier transfer and separation, thereby strengthening the antibacterial action. Moreover, the hydrogel coating exhibits excellent antibacterial and corrosion resistance capabilities against Pseudomonas aeruginosa on 316L stainless steel (316L SS), laying the foundation for advanced antimicrobial and anticorrosion hydrogel systems.