Phage-Based antibacterial hydrogels for bacterial targeting and Ablation: Progress and perspective.

The emergence of drug-resistant bacteria makes antibiotics inadequate to treat bacterial infections, which is now a global problem. Phage as a virus with specific recognition ability can effectively kill the bacteria, which is an efficacious antibacterial material to replace antibiotics. Phage-based hydrogels have good biocompatibility and antibacterial effect at the site of infection. Phage hydrogels have remarkable antibacterial effects on targeted bacteria because of their specific targeted bactericidal ability, but there are few reports and reviews on phage hydrogels. This paper discusses the construction method of phage-based antibacterial hydrogels (PAGs), summarizes the advantages related to PAGs and their applications in the direction of wound healing, treating bone bacterial infections, gastrointestinal infection treatment and other application, and finally gives an outlook on the development and research of PAGs.

Biological regulation on iodine using nano-starch for preventing thyroid dysfunction.

The growing incidence of thyroid disease triggered by excess iodine uptake poses a severe health threat throughout the world. Extracellular interference therapies impede iodine transport across the sodium-iodide symporter (NIS) membrane protein and thus prevent excessive iodine uptake by thyroid cells, which may lessen the occurrence of disease. Herein, we for the first time utilized nano-starch particles (St NPs) to regulate iodine transport across the NIS protein of thyroid cells by using extracellular interference therapy. By precisely encapsulating iodine within the cavity of a glucan α-helix via hydrogen bonding, extracellular St NPs prevented excess iodine uptake by thyroid cells in vitro and in vivo; this down-regulated the expression of NIS protein (0.06-fold) and autophagy protein LC3B-II (0.35-fold). We also found that St NPs regulated the metabolic pathway of iodine in zebrafish. We believe this proposed strategy offers a novel insight into controlling iodine uptake by the thyroid and indicates a new direction for preventing iodine-induced thyroid disease.

AIEgens for Bacterial Imaging and Ablation.

Accurate and sensitive diagnosis of pathogenic bacterial infection is a fundamental first step for correct bacteria management, helping to avoid the development of drug-resistant bacteria caused by the inappropriate use and overuse of antibiotics. Fluorescence probes as a promising visual tool can help identify pathogens rapidly and reliably. However, rigidly structured traditional fluorescence probes generally suffer from the drawback of aggregation-caused quenching (ACQ) effect, which greatly undermines their advantages with respect to sensitivity. Luminogens with aggregation-induced emission properties, namely AIEgens, can overcome the ACQ effect and certain AIEgen-based materials are capable of generating reactive oxygen species (ROS) in the aggregate states. Hence, they have become powerful tools for imaging and killing bacteria. This review summarizes the recent advances in AIEgens for the diagnosis and treatment of pathogen infections. Special attention has been paid to the molecular design, the application in bacterial imaging and ablation in vitro and in vivo, and the biocompatibility of AIEgens. Finally, the challenges and prospects are discussed in terms of using AIEgens to advance precision therapies for pathogen infections.

Cow dung-derived biochars engineered as antibacterial agents for bacterial decontamination.

Disposal of the pollutants arising from farming cattle and other livestock threatens the environment and public safety in diverse ways. Herein, we report on the synthesis of engineered biochars using cow dung as raw material, and investigating these biochars as antibacterial agents for water decontamination. By coating the biochars with N-halamine polymer and loading them with active chlorine (i.e., Cl+), we were able to regulate them on demand by tuning the polymer coating and bleaching conditions. The obtained N-halamine-modified biochars were found to be extremely potent against Escherichia coli and Staphylococcus aureus. We also investigated the possibility of using these N-halamine-modified biochars for bacterial decontamination in real-world applications. Our findings indicated that a homemade filter column packed with N-halamine-modified biochars removed pathogenic bacteria from mining sewage, dairy sewage, domestic sewage, and artificial seawater. This proposed strategy could indicate a new way for utilizing livestock pollutants to create on-demand decontaminants.

Design of nanoengineered antibacterial polymers for biomedical applications.

Pathogenic bacteria have become global threats to public health. Since the advent of antibiotics about 100 years ago, their use has been embraced with great enthusiasm because of their effective treatment of bacterial infections. However, the evolution of pathogenic bacteria with resistance to conventional antibiotics has resulted in an urgent need for the development of a new generation of antibiotics. The use of antimicrobial polymers offers the promise of enhancing the efficacy of antimicrobial agents. Of the various antibacterial polymers that effectively eradicate pathogenic bacteria, those that are nanoengineered have garnered significant research interest in their design and biomedical applications. Because of their high surface area and high reactivity, these polymers show greater antibacterial activity than conventional antibacterial agents, by inhibiting the growth or destroying the cell membrane of pathogenic bacteria. This review summarizes several strategies for designing nanoengineered antibacterial polymers, explores the factors that affect their antibacterial properties, and examines key features of their design. It then comments briefly on the future prospects for nanoengineered antibacterial polymers. This review thus provides a feasible guide to developing nanoengineered antibacterial polymers by presenting both broad and in-depth bench research, and it offers suggestions for their potential in biomedical applications.

Pyrrolidone-based polymers capable of reversible iodine capture for reuse in antibacterial applications.

Numerous emerging and re-emerging advanced materials have been successful in capturing iodine pollutants that pose an unprecedented global challenge to public health. However, little attention has been paid to the reutilization of the captured iodine. Herein, we report on a pyrrolidone-based polymer capable of reversible iodine capture for reutilization in antibacterial applications. The pyrrolidone-based polymer poly(N-vinyl-2-pyrrolidone-co-vinyl acetate), denoted as P(VAc-NVP), was synthesized facilely via a one-step radical copolymerization strategy, and the synthesis was regulated by step-by-step optimization, specifically by tuning the feed ratio of NVP to VAc. The as-synthesized P(VAc-NVP) copolymer functioned as an adsorbent for iodine in various solutions, including water/ethanol, cyclohexane, and petroleum ether, in addition to having the special capability of releasing iodine in the presence of starch or bacteria. This opens up a new horizon for its functional practical use as a flexible adsorbent to capture iodine for safe disposal. Interestingly, the P(VAc-NVP) copolymer, after adsorbing iodine, showed antibacterial ability against pathogenic bacteria, including Staphylococcus aureus and Escherichia coli, when a series of simulated and practical antibacterial assays were conducted. It is believed that this proposed strategy based on the synergism of iodine capture and antibacterial use should have great potential for environmental remediation and public healthcare.

Povidone-iodine-functionalized fluorinated copolymers with dual-functional antibacterial and antifouling activities.

Biomaterial-associated infections caused by bacterial contamination and the subsequent formation of biofilms on the surfaces are challenges faced by our healthcare system. In this work, povidone-iodine-functionalized fluorinated copolymers with stable antibacterial, antibiofilm, and antifouling activities were designed and prepared by a two-step synthesis. First, a series of poly(hexafluorobutyl methacrylate-co-N-vinyl-2-pyrrolidone), i.e., P(HFBMA-NVP), were synthesized by radical copolymerization at different feed ratios to acquire water insoluble and antifouling copolymers. At the second step, the NVP segments in the copolymer were complexed with iodine to obtain the objective antibacterial and antifouling copolymer P(HFBMA-NVP)-I. The chemical and physical characteristics of the copolymers were investigated using 1H NMR, FTIR, XPS, EDX, UV-Vis, SEM, TEM, elemental analysis, and contact angle measurement. P(HFBMA-NVP)-I exhibited excellent antibacterial activity against both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus), as well as good biocompatibility towards human hepatocyte cells (L02) and Caenorhabditis elegans. Using the electrospinning or spraying technique, P(HFBMA-NVP)-I was coated on polystyrene slides, medical stainless steel sheets, and cotton fabric, allowing the surfaces to have stable antibacterial and antibiofilm activities against pathogenic bacteria and antifouling capability against foulants and blood, and exhibit excellent self-cleaning properties.

Antibacterial Povidone-Iodine-Conjugated Cross-Linked Polystyrene Resin for Water Bacterial Decontamination.

Bacterial contamination in water purification systems is generating significant concern as a global health issue. In this paper, we describe fabricating antibacterial povidone-iodine-conjugated cross-linked polystyrene resins (i.e., P(St-DVB-NVP)-I2) and investigating them as antimicrobial agents for water decontamination. Comprehensive antibacterial tests showed that the addition of povidone-iodine to polystyrene resins resulted in strong antibacterial activity against pathogenic bacteria. In addition, the as-synthesized P(St-DVB-NVP)-I2 was confirmed to have hydrophobicity and favorable biocompatibility. We then examined the possibility of using P(St-DVB-NVP)-I2 as an antibacterial filter for water treatment and found that it could efficiently remove bacteria from water. An analog experiment demonstrated that the capability of P(St-DVB-NVP)-I2 for water bacterial decontamination was not influenced by the presence of mineral ions in the water. Most significantly, we confirmed the potential reusability of P(St-DVB-NVP)-I2 through a recycling test. This method of creating an antibacterial resin by building a conjugation of cross-linked polystyrene with povidone-iodine is safe, cost-effective, and environmentally friendly, and the resin shows promise for use in water purification filters.