Antibacterial electrospun chitosan‐based nanofibers: A bacterial membrane perforator

Abstract

This study investigates the antibacterial action of chitosan‐based nanofibers (CNFs) obtained by the electrospinning process on the permeability of bacterial membranes. The bactericidal efficiency of CNFs was first determined against Gram‐negative Escherichia coli and Salmonella Typhimurium, and Gram‐positive Staphylococcus aureus and Listeria innocua bacteria as a baseline. The results strongly suggest that CNFs interact with the negatively charged bacterial cell wall causing membrane rupture and inducing leakage of intracellular components among which are proteins and DNA. Results clearly indicate that the release of such components after contact with CNFs is an indication of membrane permeabilization and perforation, as pore formation was observed in transmission electron microscopy (TEM). This work suggests a plausible antibacterial mechanism of action of CNFs and also provides clear evidence in favor of chitosan as a bacterial membrane disruptor and perforator. As a result, CNFs can find promising applications as bioactive food packaging materials capable to extend shelf life of food products while inhibiting the spread of alteration flora and foodborne pathogens.

Chitosan‐based nanofibers as bioactive meat packaging materials

“…Figure S1 in the Supporting Information illustrates morphological differences (Gram‐type, means of motility, presence of flagella) among the tested bacteria. More details regarding the mechanism of action and the effect of CNFs on membrane integrity have been reported in another study …”

“…More details regarding the mechanism of action and the effect of CNFs on membrane integrity have been reported in another study. 49…”

Electrospinning of nanofibers: Potentials and perspectives for active food packaging

“…The electrospinability of chitosan was enhanced by the assistance of PEO as a result of strong hydrogen bonds formed between hydroxyl and amino groups in chitosan and ether groups in PEO, which provided a new approach to develop chitosan‐based electrospun fibers for antibacterial film packaging. Arkoun, Daigle, Heuzey, and Ajji () studied the antibacterial action of the chitosan‐based electrospun nanofibers on the permeability of bacterial membranes, and found that the interactions between the negatively charged bacterial cell walls and the positively charged nanofibers resulted in the membrane rupture and the leakage of intracellular components among which were proteins and DNA, indicating the promising applications of chitosan‐based electrospun nanofibers for active food packaging to extend the shelf life of food products by inhibiting the spread of foodborne pathogens and flora alteration.…”

Nanostructured Antimicrobials in Food Packaging—Recent Advances

“…Chitosan nanoparticles (CSNPs) are usually formed by electrostatic interactions of cationic NH 3 + groups with polyanions such as tripolyphosphate, while chitosan whiskers are produced from deacetylation of chitin whiskers formed by acid hydrolysis of chitin . The antimicrobial activity of chitosan is mediated by electrostatic interactions between its protonated amino groups at C‐2 (below its pKa at pH 6.3) and negative groups on microbial membranes, culminating in membrane rupture . This effect depends then on a relatively low pH, and explains why smaller particles (with higher specific surface and higher charge density) are more effective …”

“…[89] The antimicrobial activity of chitosan is mediated by electrostatic interactions between its protonated amino groups at C-2 (below its pKa at pH 6.3) and negative groups on microbial membranes, [90] culminating in membrane rupture. [91] This effect depends then on a relatively low pH, [92] and explains why smaller particles (with higher specific surface and higher charge density) are more effective. [93] The effectiveness of CSNPs has been demonstrated against G(+) and G(−) bacteria.…”