Permanent, Antimicrobial Coating to Rapidly Kill and Prevent Transmission of Bacteria, Fungi, Influenza, and SARS-CoV-2

Antimicrobial Biphasic Polymer Coatings Enabled by Fast Diffusion of Active Compounds

The recent COVID-19 pandemic and the prospect of future global pandemics highlight the long-standing need to passively eliminate viruses and bacteria on surfaces. Conventional antimicrobial surfaces and coatings are typically constrained by a trade-off between antimicrobial efficacy and physical durability. A biphasic polyurethane coating has been developed that breaks this trade-off by incorporating a durability-imparting polycarbonate (PC) discrete phase with a continuous poly(ethylene glycol) (PEG) transport phase that absorbs, stores, and releases antimicrobial active compounds for extended microbial inactivation. The biphasic polymer was shown to absorb carboxylic acid and quaternary ammonium antimicrobial active compounds, maintained their levels after five years of simulated cleaning, and inactivated up to 99.99% of Human Coronavirus 229E and Influenza A H1N1. Furthermore, the levels of antimicrobial active compounds on the biphasic coating could be augmented by cleaning the substrate with a disinfectant. The practicality of biphasic coatings for automotive and commercial aerospace environments was demonstrated by showing control of hardness and stain resistance through biphasic composition, showing environmental durability through heat, humidity, and light exposure, and passing flammability protocols.

Functional Zwitterionic Polyurethanes: State-of-the-Art Review

Recent advancements in bioengineering and medical devices have been greatly influenced and dominated by synthetic polymers, particularly polyurethanes (PUs). PUs offer customizable mechanical properties and long-term stability, but their inherent hydrophobic nature poses challenges in practically biological application processes, such as interface high friction, strong protein adsorption, and thrombosis. To address these issues, surface modifications of PUs for generating functionally hydrophilic layers have received widespread attention, but the durability of generated surface functionality is poor due to irreversible mechanical wear or biodegradation. As a result, numerous researchers have investigated bulk modification techniques to incorporate zwitterionic polymers or groups onto the main or side chains of PUs, thereby improving their hydrophilicity and biocompatibility. This comprehensive review presents an extensive overview of notable zwitterionic PUs (ZPUs), including those based on phosphorylcholine, sulfobetaine, and carboxybetaine. The review explores their wide range of biomedical applications, from blood-contacting devices to antibacterial coatings, fouling-resistant marine coatings, separation membranes, lubricated surfaces, and shape memory and self-healing materials. Lastly, the review summarizes the challenges and future prospects of ZPUs in biological applications.

Multifunctional Suture Coating for Combating Surgical Site Infections and Mitigating Associated Complications

Despite advancements in preventive measures and hospital protocols, surgical site infections (SSIs) remain a significant concern following surgeries. Sutures, commonly used for wound closure, can serve as a platform for microbial adherence and contamination, leading to extensive debridement and recurrent antibiotic therapy. The emergence of drug resistance and the formation of biofilms on sutures have further complicated the management of SSIs. Drug-eluting sutures incorporating biocides like triclosan have limitations due to uncontrolled release and associated toxicity. Therefore, there is a need for alternative approaches to impart antimicrobial properties to sutures. In this study, we present a one-step covalent cross-linking method to coat surgical sutures with an antimicrobial small molecule, quaternary benzophenone-based antimicrobial (QSM). Additionally, the sutures are dip-coated with ibuprofen, a nonsteroidal anti-inflammatory drug with analgesic properties. The coated sutures maintained their morphological and tensile properties after in vivo implantation. The antimicrobial coating demonstrated efficacy against a broad-spectrum pathogens, including drug-resistant bacteria and fungi. The optimized formulation retained its biodegradability in vivo. Furthermore, the coated sutures exhibited ∼3 log reduction in methicillin-resistant Staphylococcus aureus (MRSA) burden in a subcutaneous implantation mouse model. Overall, this multifunctional coating provides antimicrobial properties to surgical sutures while preserving their mechanical integrity and biodegradability. These coated sutures have the potential to address the challenge of SSIs and contribute to improved surgical outcomes.

Facile Construction of Antimicrobial Surface via One-Step Co-Deposition of Peptide Polymer and Dopamine

The infections associated with implantable medical devices can greatly affect the therapeutic effect and impose a heavy financial burden. Therefore, it is of great significance to develop antimicrobial biomaterials for the prevention and mitigation of healthcare-associated infections. Here, a facile construction of antimicrobial surface via one-step co-deposition of peptide polymer and dopamine is reported. The co-deposition of antimicrobial peptide polymer DLL60 BLG40 with dopamine (DA) on the surface of thermoplastic polyurethane (TPU) provides peptide polymer-modified TPU surface (TPU-DLL60 BLG40 ). The antimicrobial test shows that the TPU-DLL60 BLG40 surfaces of the sheet and the catheter both exhibit potent killing of 99.9% of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). In addition, the TPU-DLL60 BLG40 surface also exhibits excellent biocompatibility. This one-step antimicrobial modification method is fast and efficient, implies promising application in surface antimicrobial modification of implantable biomaterials and medical devices.

Robust and Transparent Silver Oxide Coating Fabricated at Room Temperature Kills Clostridioides difficile Spores, MRSA, and Pseudomonas aeruginosa

Antimicrobial coatings can inhibit the transmission of infectious diseases when they provide a quick kill that is achieved long after the coating application. Here, we describe the fabrication and testing of a glass coating containing Ag2O microparticles that was prepared from sodium silicate at room temperature. The half-lives of both methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa on this coating are only 2-4 min. The half-life of Clostridioides difficile spores is about 9-12 min, which is extremely short for a spore. Additional tests on MRSA demonstrate that the coating retains its antimicrobial activity after abrasion and that an increased loading of Ag2O leads to a shorter half-life. This coating combines the properties of optical transparency, robustness, fast kill, and room temperature preparation that are highly desirable for an antimicrobial coating.

Structurally Heterogeneous Amphiphilic Conetworks of Poly(vinyl imidazole) Derivatives with Potent Antimicrobial Properties and Cytocompatibility

We report the construction of amphiphilic conetwork (APCN)-based surfaces with potent antimicrobial activity and biofilm inhibition ability. The construction strategy is based on the separation of lipophilic alkyl groups (>C6) from the cationic network to obtain good antibacterial properties. The reaction of partially alkylated poly(vinyl imidazole) with the activated halide compounds followed by coating a glass or poly(dimethylsiloxane) (PDMS) sheet leads to the formation of the APCN surface. The dangling alkyl chains, crosslinking junctions, and unreacted vinyl imidazole groups are heterogeneously distributed in the APCNs. The swelling, mechanical property, and phase morphology of the APCN films have been evaluated. Bacterial cell disrupting potency of the APCN coatings increases with increasing alkyl chain length from C6 to C18 with somewhat more of an effect on Escherichia coli as compared to Bacillus subtilis bacteria. The minimum inhibitory amount of the APCNs on glass and a hydrophobic PDMS surface is in the range of 0.02-0.04 mg/cm2 depending on the chain length of the alkyl and the degree of quaternization. The effect of the type of crosslinker for the construction of the conetwork on the antimicrobial property has been evaluated to elucidate the exclusive design of the APCNs. The APCN-based coatings provide potent biocidal activity without much negatively affecting the hemocompatibility and cytocompatibility. These APCNs provide a good model system for comparative evaluation of the biocidal property and structural effect on the biocidal activity.

Electrospun Metal-Organic Framework-Fabric Nanocomposites as Efficient Bactericides

In this work, we utilized electrospinning to develop advanced composite membranes of polyvinyl chloride (PVC) loaded with postmetalated metal-organic frameworks (MOFs), specifically UiO-66(COOH)₂-Ag and ZIF-8-Ag. This innovative technique led to the creation of highly stable PVC/MOFs-Ag membrane composites, which were thoroughly characterized using various analytical techniques, including scanning electron microscopy, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, porosity analysis, and water contact angle measurement. The results verified the successful integration of MOF crystals within the nanofibrous PVC membranes. The obtained composites exhibited larger fiber diameters for 5 and 10% MOF loadings and a smaller diameter for 20% loading. Additionally, they displayed greater average pore sizes than traditional PVC membranes across most MOF loading percentages. Furthermore, we examined the antibacterial properties of the fabricated membranes at different MOFs-Ag loadings. The findings revealed that the membranes demonstrated significant antibacterial activity up to 95% against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria as the MOFs-Ag loading increased, even when maintaining a constant silver concentration. This indicates a contact-based inhibition mechanism. The outcomes of this study have crucial implications for the development of novel, stable, and highly effective antibacterial materials, which could serve as superior alternatives for face masks and be integrated into materials requiring regular decontamination, as well as potential water filtration systems.

Engineering Photo-Crosslinked Antimicrobial Coating to Tackle Catheter-Associated Infections In Vivo

Microbial colonization on urinary and intravascular catheter surfaces results in steeply rising cases of catheter-associated infections as well as blood stream infections. Currently marketed efforts include impregnation and loading of antimicrobials and antiseptics that leach out into the local environment and inactivate microbes. However, they suffer from uncontrolled release, induction of resistance, and undesired toxicity. Here, in this manuscript, we have developed a photocurable, covalent coating on catheters using quaternary benzophenone-based amide (QSM-1). The coating was found to be active against drug-resistant bacteria and fungi. The coating inactivated stationary and persister cells of superbug MRSA and inhibited the formation of biofilms with retained activity against broad-spectrum bacteria when challenged in realistic urinary conditions. The coating was seen to be biocompatible in vitro and in vivo. Remarkably, the coated catheters showed reduced fouling and >99.9% reduction in bacterial burden when implanted in vivo in a mice model of subcutaneous implantation. We conceive the possibility of application of QSM-1-coated catheters in the healthcare settings to tackle the notorious catheter-associated nosocomial infections.

Advancements of Nanotechnology and Nanomaterials in Environmental and Human Protection for Combatting the COVID-19 During and Post-pandemic Era: A Comprehensive Scientific Review

In December 2019, an outbreak of unknown pneumonia emerged in Wuhan City, Hubei Province, China. It was later identified as the SARS-CoV-2 virus and has since infected over 9 million people in more than 213 countries worldwide. Massive papers on the topic of SARS-CoV-2 that have already been published are necessary to be analyzed and discussed. This paper used the combination of systematic literature network analysis and content analysis to develop a comprehensive discussion related to the use of nanotechnology and materials in environmental and human protection. Its is shown that various efforts have been made to control the transmission of this pandemic. Nanotechnology plays a crucial role in modern vaccine design, as nanomaterials are essential tools for antigen delivery, adjuvants, and mimics of viral structures. In addition, nanomaterials and nanotechnology also reported a crucial role in environmental protection for defence and treating the pandemic. To eradicate pandemics now and in the future, successful treatments must enable rapid discovery, scalable manufacturing, and global distribution. In this review, we discuss the current approaches to COVID-19 development and highlight the critical role of nanotechnology and nanomaterials in combating the virus in the human body and the environment.

Controlled Iodine Phase Transfer of Covalent Organic Framework Membranes for Instant but Sustained Disinfection

Freestanding membranes of CuCl₂-implanted TpPa covalent organic frameworks (COFs) were mechanochemically produced. The resulting membrane had a high I₂ adsorption capacity (566.78 g·mol^-1) in cyclohexane, which corresponds to 2.2I₂ per unit cell with 1.3I₂ immobilized on 3Cl^- ions (60%) and 0.9 on 3N atoms (40%). Upon being placed in aqueous media, the membrane released 61.1% of its loaded I₂ mainly by its Cl^- ions within 10 min and the remaining 38.9% mainly from its N atoms within about 5 h. Thanks to that, the COF membranes loaded with 1.5 mg of I₂ could be repetitively utilized to kill about 10⁸ CFU/mL E. coli in 0.5-3 min at least five times, after which the membranes could retain their bactericidal activity for 4 h against 10⁸ CFU/mL E. coli. This highlights the promising application of I₂-loaded TpPa-CuCl₂ COF membranes for instant and sustained disinfection.