EGCG-coated silver nanoparticles self-assemble with selenium nanowires for treatment of drug-resistant bacterial infections by generating ROS and disrupting biofilms

Natural Products from Herbal Medicine Self-Assemble into Advanced Bioactive Materials

Novel biomaterials are becoming more crucial in treating human diseases. However, many materials require complex artificial modifications and synthesis, leading to potential difficulties in preparation, side effects, and clinical translation. Recently, significant progress has been achieved in terms of direct self-assembly of natural products from herbal medicine (NPHM), an important source for novel medications, resulting in a wide range of bioactive supramolecular materials including gels, and nanoparticles. The NPHM-based supramolecular bioactive materials are produced from renewable resources, are simple to prepare, and have demonstrated multi-functionality including slow-release, smart-responsive release, and especially possess powerful biological effects to treat various diseases. In this review, NPHM-based supramolecular bioactive materials have been revealed as an emerging, revolutionary, and promising strategy. The development, advantages, and limitations of NPHM, as well as the advantageous position of NPHM-based materials, are first reviewed. Subsequently, a systematic and comprehensive analysis of the self-assembly strategies specific to seven major classes of NPHM is highlighted. Insights into the influence of NPHM structural features on the formation of supramolecular materials are also provided. Finally, the drivers and preparations are summarized, emphasizing the biomedical applications, future scientific challenges, and opportunities, with the hope of igniting inspiration for future research and applications.

Polyethyleneimine surface-modified silver-selenium nanocomposites for anti-infective treatment of wounds by disrupting biofilms

Bacterial biofilm formation is associated with the pathogenicity of pathogens and poses a serious threat to human health and clinical therapy. Complex biofilm structures provide physical barriers that inhibit antibiotic penetration and inactivate antibiotics via enzymatic breakdown. The development of biofilm-disrupting nanoparticles offers a promising strategy for combating biofilm infections. Hence, polyethyleneimine surface-modified silver-selenium nanocomposites, Ag@Se@PEI (ASP NCs), were designed for synergistic antibacterial effects by destroying bacterial biofilms to promote wound healing. The results ofin vitroantimicrobial experiments showed that, ASP NCs achieved efficient antibacterial effects againstStaphylococcus aureus (S. aureus)andEscherichia coli (E. coli)by disrupting the formation of the bacterial biofilm, stimulating the outbreak of reactive oxygen species and destroying the integrity of bacterial cell membranes. Thein-vivobacterial infection in mice model showed that, ASP NCs further promoted wound healing and new tissue formation by reducing inflammatory factors and promoting collagen fiber formation which efficiently enhanced the antibacterial effect. Overall, ASP NCs possess low toxicity and minimal side effects, coupled with biocompatibility and efficient antibacterial properties. By disrupting biofilms and bacterial cell membranes, ASP NCs reduced inflammatory responses and accelerated the healing of infected wounds. This nanocomposite-based study offers new insights into antibacterial therapeutic strategies as potential alternatives to antibiotics for wound healing.

EGCG-based nanoparticles: synthesis, properties, and applications

(-)-Epigallocatechin-3-gallate (EGCG) is a natural phenolic substance found in foods and beverages (especially tea) that exhibits a broad spectrum of biological activities, including antioxidant, antimicrobial, anti-obesity, anti-inflammatory, and anti-cancer properties. Its potential in cardiovascular and brain health has garnered significant attention. However, its clinical application remains limited due to its poor physicochemical stability and low oral bioavailability. Nanotechnology can be used to improve the stability, efficacy, and pharmacokinetic profile of EGCG by encapsulating it within nanoparticles. This article reviews the interactions of EGCG with various compounds, the synthesis of EGCG-based nanoparticles, the functional attributes of these nanoparticles, and their prospective applications in drug delivery, diagnosis, and therapy. The potential application of nanoencapsulated EGCG in functional foods and beverages is also emphasized. Top-down and bottom-up approaches can be used to construct EGCG-based nanoparticles. EGCG-based nanoparticles exhibit enhanced stability and bioavailability compared to free EGCG, making them promising candidates for biomedical and food applications. Notably, the non-covalent and covalent interactions of EGCG with other substances significantly contribute to the improved properties of these nanoparticles. EGCG-based nanoparticles appear to have a wide range of applications in different industries, but further research is required to enhance their efficacy and ensure their safety.

Polyphenols and their nanoformulations as potential antibiofilm agents against multidrug-resistant pathogens

The emergence of multidrug-resistant (MDR) pathogens is a major problem in the therapeutic management of infectious diseases. Among the bacterial resistance mechanisms is the development of an enveloped protein and polysaccharide-hydrated matrix called a biofilm. Polyphenolics have demonstrated beneficial antibacterial effects. Phenolic compounds mediate their antibiofilm effects via disruption of the bacterial membrane, deprivation of substrate, protein binding, binding to adhesion complex, viral fusion blockage and interactions with eukaryotic DNA. However, these compounds have limitations of chemical instability, low bioavailability, poor water solubility and short half-lives. Nanoformulations offer a promising solution to overcome these challenges by enhancing their antibacterial potential. This review summarizes the antibiofilm role of polyphenolics, their underlying mechanisms and their potential role as resistance-modifying agents.

Bimetallic CoSn nanoparticles anchored on N-doped carbon as antibacterial oxygen reduction catalysts for microbial fuel cells

Sluggish oxygen reduction reaction (ORR) kinetics and biofilm formation limit the power generation and stability of microbial fuel cells (MFCs). Herein, bimetallic CoSn nanoparticles anchored on ZIF-derived N-doped carbon (CoSn@NC) were designed and synthesized as bifunctional catalysts to accelerate the ORR and improve the antibacterial activity. Sn modulated the electronic structure of bimetallic CoSn by drawing electrons from Co. Electron redistribution of CoSn@NC optimized the O2 adsorption at Co sites for rapid ORR kinetics. The up-shifted d-band center of Co sites reduced the energy barrier of the rate-determining step for *O formation, resulting in efficient catalytic activity. Bimetallic CoSn nanoparticles were beneficial for the four-electron transfer process for more ˙OH species production. Sn2+ and ˙OH synergistically improved the antibacterial activity of CoSn@NC to inhibit the growth of the cathode biofilm and accelerate mass-charge transfer. CoSn@NC demonstrated superior oxygen reduction activity with a half-wave potential of 0.84 V and an onset potential of 0.90 V, respectively. The MFCs assembled with the CoSn@NC cathodic catalyst exhibited an excellent power density of 1380 mW m-2 and long-term stability for 105 h. This work provides a strategy for the design of antibacterial ORR catalysts for improved catalytic activity and long-term stability.

Drug delivery strategies for antibiofilm therapy

Although new antibiofilm agents have been developed to prevent and eliminate pathogenic biofilms, their widespread clinical use is hindered by poor biocompatibility and bioavailability, unspecific interactions and insufficient local concentrations. The development of innovative drug delivery strategies can facilitate penetration of antimicrobials through biofilms, promote drug dispersal and synergistic bactericidal effects, and provide novel paradigms for clinical application. In this Review, we discuss the potential benefits of such emerging techniques for improving the clinical efficacy of antibiofilm agents, as well as highlighting the existing limitations and future prospects for these therapies in the clinic.

Mild Heat-Assisted Polydopamine/Alginate Hydrogel Containing Low-Dose Nanoselenium for Facilitating Infected Wound Healing

In clinical practice, it has become urgent to develop multifunctional wound dressings that can combat infection and prompt wound healing simultaneously. In this study, we proposed a polydopamine/alginate/nanoselenium composite hydrogel (Alg-PDA-Se) for the treatment of infected wounds. In particular, polydopamine endows the composite hydrogel with controllable near-infrared photothermal properties, while low-dosage selenium nanoparticles (Se NPs) offer excellent anti-oxidation, anti-inflammatory, pro-proliferative, pro-migration, and pro-angiogenic performances, which are verified by multiple cells, including macrophages, fibroblasts, and endothelial cells. More interestingly, the combination of mild temperature with low-dosage Se NPs produces a synergistic effect on combating both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and promoting the healing of bacteria-infected wounds in vivo. We anticipate that the designed composite hydrogel might be a potential candidate for anti-infection bioactive dressing.