Green antimicrobial coating based on quaternised chitosan/organic montmorillonite/Ag NPs nanocomposites

Abstract

This work is aimed at developing a green antimicrobial coating. First, a green antimicrobial agent, quaternised chitosan (QCS)/organic montmorillonite (OMMT)/silver nanoparticles (Ag NPs) (QOMA) nanocomposite was fabricated through an environmental-friendly one-step approach. Morphological and structural characteristics of QOMA were investigated, and good antimicrobial activity was proved. QOMA was then incorporated into powder coating formulations to form a homogeneous coating on steel plates, which was studied by scanning electron images. Besides, the physical and mechanical properties as well as the antimicrobial performances of the coatings were discussed. The results showed that the addition of QOMA imparted good antimicrobial capacity to the powder coating, but did not affect its physical and mechanical properties. The coatings were able to effectively inactivate Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus) and fungi (Aspergillus niger, Penicillium funiculosum, Chaetomium globasum, Paecilomyces varioti, Asp. terreus and Aureobasidium pullulans). Our findings demonstrate the possibilities of green antimicrobial coating containing QOMA for practical applications in medical devices, domestic appliances and other solid surfaces concerning bacterial infection and contamination.

A Review on Montmorillonite-Based Nanoantimicrobials: State of the Art

“…Another study was dedicated to synthesizing quaternized chitosan (QCS)/(OMMT)/(AgNPs)(QOMA) nanocomposite by the one-step approach, and to investigate the antibacterial activity of QOMA coating on steel plates towards E. coli, S. aureus, and fungi. Moreover, physical and mechanical investigation revealed no negative effect of QOMA coating on steel plates; instead, hydroxyl groups in QOMA act as adhesive [39]. Later, migration of cetylpyridinium bromide (CPB) from the low density polyethylene/MMT/CPB composite to aqueous food simulant was studied, proposing MMT as potential surfactant carrier [132].…”

“…MMT can be exfoliated into nanosheets used in a wide range of applications as two dimensional (2D) material. Metal NP-clay-polymer composite find potential applications in food packaging and biomedical fields, due to the formation of exfoliated nanocomposite heterostructures with a random dispersion of bioactive metal NPs on the polymer matrix, limiting the diffusion of metal ions, and slowing down their release, reducing water and oxygen permeability, and modifying antimicrobial activity [38][39][40]. In particular, the bacterial cell wall contains lipoprotein, which exhibits a net negative charge under physiological conditions because of the presence of functional groups such as phosphate, carboxyl, and hydroxyl.…”

Nanostructured Colloids in Food Science

“…For example, colloidal AgNPs have been for long known to be effective antibacterials. They are reported by several authors [30,31] Other nanocolloidal systems (e.g. TiO 2 -NPs, SiO 2 -NPs, nanoclays) can ensure good food preservation by blocking the UV radiation, improving mechanical and heat-resistance properties, reducing the permeability of foils, deodorizing, antimicrobials [32].…”

Combinations of Antimicrobial Polymers with Nanomaterials and Bioactives to Improve Biocidal Therapies

“…It works as an ion capping agent to control the growth of NPs and avoids their aggregation. Several studies reported the synthesis of composites based on a combination of AgNPs [110,111,112,113,114] and AuNPs [115] with CS, in which the biocidal action is exclusively attributed to nanomaterials, preventing a synergistic effect. This phenomenon may be attributed to CS as it loses its positive charges via a neutralization process or chemical modifications, which limit its antibacterial properties.…”