Precisely modulated 2D PdCu alloy nanodendrites as highly active peroxidase mimics for the elimination of biofilms

Advanced nanozymes possess peroxidase-like catalytic activities in biomedical and antibacterial fields: review and progress

Infectious diseases caused by bacterial invasions have imposed a significant global health and economic burden. More worryingly, multidrug-resistant (MDR) pathogenic bacteria born under the abuse of antibiotics have further escalated the status quo. Nowadays, at the crossroads of multiple disciplines such as chemistry, nanoscience and biomedicine, nanozymes, as enzyme-mimicking nanomaterials, not only possess excellent bactericidal ability but also reduce the possibility of inducing resistance. Thus, nanozymes are promising to serve as an alternative to traditional antibiotics. Nanozymes that mimic peroxidase (POD) activity are also known as POD nanozymes. In recent years, POD nanozymes have become one of the most frequently reported and effective nanozymes due to their broad-spectrum bactericidal properties and unique sterilization mechanism. In this review, we introduce the mechanism as well as the classification of POD nanozymes. More importantly, to further improve the antibacterial efficacy of POD nanozymes, we elaborate on three aspects: (1) improving the physicochemical properties; (2) regulating the catalytic microenvironment; and (3) designing multimodel POD nanozymes. In addition, we review the nanosafety of POD nanozymes for discussing their potential toxicity. Finally, the remaining challenges of POD nanozymes and possible future directions are discussed. This work provides a systematic summary of POD nanozymes and hopefully contributes to the early clinical translation.

Recent Advances of Composite Nanomaterials for Antibiofilm Application

A biofilm is a microbial community formed by bacteria that adsorb on the surface of tissues or materials and is wrapped in extracellular polymeric substances (EPS) such as polysaccharides, proteins and nucleic acids. As a protective barrier, the EPS can not only prevent the penetration of antibiotics and other antibacterial agents into the biofilm, but also protect the bacteria in the biofilm from the attacks of the human immune system, making it difficult to eradicate biofilm-related infections and posing a serious threat to public health. Therefore, there is an urgent need to develop new and efficient antibiofilm drugs. Although natural enzymes (lysozyme, peroxidase, etc.) and antimicrobial peptides have excellent bactericidal activity, their low stability in the physiological environment and poor permeability in biofilms limit their application in antibiofilms. With the development of materials science, more and more nanomaterials are being designed to be utilized for antimicrobial and antibiofilm applications. Nanomaterials have great application prospects in antibiofilm because of their good biocompati-bility, unique physical and chemical properties, adjustable nanostructure, high permeability and non-proneness to induce bacterial resistance. In this review, with the application of composite nanomaterials in antibiofilms as the theme, we summarize the research progress of three types of composite nanomaterials, including organic composite materials, inorganic materials and organic-inorganic hybrid materials, used as antibiofilms with non-phototherapy and phototherapy modes of action. At the same time, the challenges and development directions of these composite nanomaterials in antibiofilm therapy are also discussed. It is expected we will provide new ideas for the design of safe and efficient antibiofilm materials.

Application of f-FeNC@GOx cascade enzyme nanomaterials in the healing of infected wounds

AIMS

Bacterial infection is a significant factor contributing to the deterioration of wounds, and the misuse of antibiotics has exacerbated bacterial resistance. Therefore, there is an urgent need to develop a novel antibacterial strategy to replace conventional therapies. This study aims to construct a self-activated cascade reaction nanozyme, f-FeNC@GOx, which triggers a cascade reaction in the presence of glucose. This cascade reaction generates highly toxic hydroxyl radicals (OH), thereby achieving the goal of eliminating bacteria and promoting wound healing.

MATERIAL AND METHODS

In vitro antibacterial experiments, bacterial spread plate method, Live/Dead staining, and crystal violet staining were conducted to analyze the antibacterial ability and mechanism of f-FeNC@GOx. In vivo experiments, a mouse wound model was established, and H&E and Masson staining of wound tissues were performed to assess the antibacterial activity of the f-FeNC@GOx in vivo.

KEY FINDINGS

The in vivo and in vitro experiments confirmed that f-FeNC@GOx exhibited significant antibacterial effect against both Staphylococcus aureus and Escherichia coli in the presence of glucose. Furthermore, it showed optimal wound healing performance in the wound models.

SIGNIFICANCE

These findings suggested that f-FeNC@GOx was a novel and effective antibacterial nanomaterial, which provided a promising antibacterial strategy using nanoenzyme based cascade reaction.