The spread of infections in healthcare environments is a persistent and growing problem in most countries, aggravated by the development of microbial resistance to antibiotics and disinfectants. In addition to indwelling medical devices (e.g. implants, catheters), such infections may also result from adhesion of microbes either to external solid-water interfaces such as shower caps, taps, drains, etc., or to external solid-gas interfaces such as door handles, clothes, curtains, computer keyboards, etc. The latter are the main focus of the present work, where an overview of antimicrobial coatings for such applications is presented. This review addresses well-established and novel methodologies, including chemical and physical functional modification of surfaces to reduce microbial contamination, as well as the potential risks associated with the implementation of such anticontamination measures. Different chemistry-based approaches are discussed, for instance anti-adhesive surfaces (e.g. superhydrophobic, zwitterions), contact-killing surfaces (e.g. polymer brushes, phages), and biocide-releasing surfaces (e.g. triggered release, quorum sensing-based systems). The review also assesses the impact of topographical modifications at distinct dimensions (micrometre and nanometre orders of magnitude) and the importance of applying safe-by-design criteria (e.g. toxicity, contribution for unwanted acquisition of antimicrobial resistance, long-term stability) when developing and implementing antimicrobial surfaces.

Exopolysaccharides (EPSs) are a diverse class of biopolymers synthesized by microorganisms under environmental stress conditions, such as pH, temperature, light intensity, and salinity. They offer biodegradable and environmentally friendly alternatives to synthetic polymers. Their structural versatility and functional properties make them unique in various industries, including food, pharmaceuticals, biomedicine, cosmetics, textiles, petroleum, and environmental remediation. In this way, among the well-known EPSs, homopolysaccharides like dextran, bacterial cellulose, curdlan, and levan, as well as heteropolysaccharides like xanthan gum, alginate, gellan, and kefiran, have found widespread applications in numerous fields. However, recent attention has focused on the potential role of extremophile bacteria in producing EPSs with novel and unusual protective and biological features under extreme conditions. Therefore, this review provides an overview of the functional properties and applications of the commonly employed EPSs. It emphasizes their importance in various industries and scientific endeavors while highlighting the raised interest in exploring EPSs with novel compositions, structures, and properties, including underexplored protective functionalities. Nevertheless, despite the potential benefits of EPSs, challenges persist. Hence, this review discusses these challenges, explores opportunities, and outlines future directions, focusing on their impact on developing innovative, sustainable, and functional materials.

A large group of low molecular weight natural compounds that exhibit antimicrobial activity has been isolated from animals and plants during the past two decades. Among them, peptides are the most widespread resulting in a new generation of antimicrobial agents with higher specific activity. In the present study we have developed a new strategy to obtain antimicrobial wound-dressings based on the incorporation of antimicrobial peptides into polyelectrolyte multilayer films built by the alternate deposition of polycation (chitosan) and polyanion (alginic acid sodium salt) over cotton gauzes. Energy dispersive X ray microanalysis technique was used to determine if antimicrobial peptides penetrated within the films. FTIR analysis was performed to assess the chemical linkages, and antimicrobial assays were performed with two strains: Staphylococcus aureus (Gram-positive bacterium) and Klebsiella pneumonia (Gram-negative bacterium). Results showed that all antimicrobial peptides used in this work have provided a higher antimicrobial effect (in the range of 4 log-6 log reduction) for both microorganisms, in comparison with the controls, and are non-cytotoxic to normal human dermal fibroblasts at the concentrations tested.

The United Nations 2030 Agenda for Sustainable Development has created more pressure on countries and society at large for the development of alternative solutions for synthetic and fossil fuel derived products, thus mitigating climate change and environmental hazards. Food wastes and microalgae have been studied for decades as potential sources of several compounds that could be employed in various fields of application from pharmaceutical to textile and packaging. Although multiple research efforts have been put towards extracting rich compounds (i.e., phenolic compounds, tocopherols, and tocotrienols) from these sources, they still remain overlooked as two major sources of bioactive compounds and pigments, mainly due to inefficient extraction processes. Hence, there is a growing need for the development of optimized extraction methods while employing non-organic solvent options following the main principles of green chemistry. This review will focus on delivering a clear and deep analysis on the existing procedures for obtaining bioactive compounds and pigments from food wastes derived from the most consumed and produced fruit crops in the world such as apples, oranges, cherries, almonds, and mangoes, and microalgal biomass, while giving light to the existing drawbacks in need to be solved in order to take full advantage of the rich properties present in these two major biorefinery sources.