The Effect of Molecular Weight on the Antimicrobial Activity of Chitosan from Loligo opalescens for Food Packaging Applications

Bioactive and biodegradable cotton fabrics produced via synergic effect of plant extracts and essential oils in chitosan coating system

Functional antibacterial textile materials are in great demand in the medical sector. In this paper, we propose a facile, eco-friendly approach to the design of antibacterial biodegradable cotton fabrics. Cotton fiber fabrics were enhanced with a chitosan coating loaded with plant extracts and essential oils. We employed Fourier-transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometry, optical microscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) to characterize the color, structure, and thermal properties of the modified fabrics. The fabrics were found to effectively induce growth inhibition of Gram-positive and Gram-negative bacteria, especially when a synergic system of aloe vera extract and cinnamon essential oil was applied in the coating formulation. Additionally, we observed significant color and weight changes after 5, 10, and 20 days in soil biodegradability tests. Given the straightforward modification process and the use of non-toxic natural materials, these innovative bio-based and biodegradable cotton fabrics show great promise as protective antimicrobial textiles for healthcare applications.

Advancements in coating technologies: Unveiling the potential of chitosan for the preservation of fruits and vegetables

Post-harvest losses of fruits and vegetables pose a significant challenge to the agriculture industry worldwide. To address this issue, researchers have turned to natural and eco-friendly solutions such as chitosan coatings. Chitosan, a biopolymer derived from chitin, has gained considerable attention due to its unique properties such as non-toxicity, biodegradability, biocompatibility and potential applications in post-harvest preservation. This review article provides an in-depth analysis of the current state of research on chitosan coatings for the preservation of fruits and vegetables. Moreover, it highlights the advantages of using chitosan coatings, including its antimicrobial, antifungal, and antioxidant properties, as well as its ability to enhance shelf-life and maintain the quality attributes of fresh product. Furthermore, the review discusses the mechanisms by which chitosan interacts with fruits and vegetables, elucidating its antimicrobial activity, modified gas permeability, enhanced physical barrier and induction of host defense responses. It also examines the factors influencing the effectiveness of chitosan coatings, such as concentration, molecular weight, deacetylation degree, pH, temperature, and application methods.

A comprehensive review of chitosan applications in paper science and technologies

Using environmentally friendly biomaterials in different aspects of human life has been considered extensively. In this respect, different biomaterials have been identified and different applications have been found for them. Currently, chitosan, the well-known derivative of the second most abundant polysaccharide in the nature (i.e., chitin), has been receiving a lot of attention. This unique biomaterial can be defined as a renewable, high cationic charge density, antibacterial, biodegradable, biocompatible, non-toxic biomaterial with high compatibility with cellulose structure, where it can be used in different applications. This review takes a deep and comprehensive look at chitosan and its derivative applications in different aspects of papermaking.

Assessment of the Antibiofilm Performance of Chitosan-Based Surfaces in Marine Environments

Marine biofouling is a natural process often associated with biofilm formation on submerged surfaces, creating a massive economic and ecological burden. Although several antifouling paints have been used to prevent biofouling, growing ecological concerns emphasize the need to develop new and environmentally friendly antifouling approaches such as bio-based coatings. Chitosan (CS) is a natural polymer that has been widely used due to its outstanding biological properties, including non-toxicity and antimicrobial activity. This work aims to produce and characterize poly (lactic acid) (PLA)-CS surfaces with CS of different molecular weight (Mw) at different concentrations for application in marine paints. Loligo opalescens pens, a waste from the fishery industry, were used as a CS source. The antimicrobial activity of the CS and CS-functionalized surfaces was assessed against Cobetia marina, a model proteobacterium for marine biofouling. Results demonstrate that CS targets the bacterial cell membrane, and PLA-CS surfaces were able to reduce the number of culturable cells up to 68% compared to control, with this activity dependent on CS Mw. The antifouling performance was corroborated by Optical Coherence Tomography since PLA-CS surfaces reduced the biofilm thickness by up to 36%, as well as the percentage and size of biofilm empty spaces. Overall, CS coatings showed to be a promising approach to reducing biofouling in marine environments mimicked in this work, contributing to the valorization of fishing waste and encouraging further research on this topic.

Recent Advances in PLA-Based Antibacterial Food Packaging and Its Applications

In order to reduce environmental pollution and resource waste, food packaging materials should not only have good biodegradable ability but also effective antibacterial properties. Poly(lactic acid) (PLA) is the most commonly used biopolymer for food packaging applications. PLA has good physical properties, mechanical properties, biodegradability, and cell compatibility but does not have inherent antibacterial properties. Therefore, antibacterial packaging materials based on PLA need to add antibacterial agents to the polymer matrix. Natural antibacterial agents are widely used in food packaging materials due to their low toxicity. The high volatility of natural antibacterial agents restricts their application in food packaging materials. Therefore, appropriate processing methods are particularly important. This review introduces PLA-based natural antibacterial food packaging, and the composition and application of natural antibacterial agents are discussed. The properties of natural antibacterial agents, the technology of binding with the matrix, and the effect of inhibiting various bacteria are summarized.

Nanoparticles of Lignins and Saccharides from Fishery Wastes as Sustainable UV-Shielding, Antioxidant, and Antimicrobial Biofillers

Lignin nanoparticles containing saccharides from fishery wastes were prepared as sustainable biofillers for advanced materials. Organosolv lignin and Kraft lignin were used as polyphenol components in association with chitosan and chitooligosaccharides. The chemophysical and biological activities of lignin/saccharide nanoparticles, such as UV-shielding, antioxidant, and antimicrobial activities, were found to be dependent on both molecular weight and deacetylation degree of saccharides, with the best performance being obtained in the presence of low-molecular-weight and highly deacetylated chitooligosaccharides. In addition, chitooligosaccharides showed a synergistic antioxidant effect with lignins, associated with antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive).

Antimicrobial adhesive films by plasma-enabled polymerisation of m-cresol

This work reveals a versatile new method to produce films with antimicrobial properties that can also bond materials together with robust tensile adhesive strength. Specifically, we demonstrate the formation of coatings by using a dielectric barrier discharge (DBD) plasma to convert a liquid small-molecule precursor, m-cresol, to a solid film via plasma-assisted on-surface polymerisation. The films are quite appealing from a sustainability perspective: they are produced using a low-energy process and from a molecule produced in abundance as a by-product of coal tar processing. This process consumes only 1.5 Wh of electricity to create a 1 cm² film, which is much lower than other methods commonly used for film deposition, such as chemical vapour deposition (CVD). Plasma treatments were performed in plain air without the need for any carrier or precursor gas, with a variety of exposure durations. By varying the plasma parameters, it is possible to modify both the adhesive property of the film, which is at a maximum at a 1 min plasma exposure, and the antimicrobial property of the film against Escherichia coli, which is at a maximum at a 30 s exposure.