Morphological Analysis of the Antibacterial Action of Chitosan on Gram-Negative Bacteria Using Atomic Force Microscopy

Abstract

Chitosan, as a cationic natural polymer, has been widely used as antibacterial, nontoxic, biocompatible and biodegradable properties. The main objective of this study was to elucidate the antibacterial effect of chitosan upon Serratia marcescens and   Enterobacter aerogenes, which are food contaminated an important organism in food production. Atomic force microscopy (AFM) was used to study effect of chitosan on the bacterial morphology.

The use of AFM imaging studies helped us to understand how chitosan act differently upon Serratia marcescens and   Enterobacter aerogenes.

Chitosan thus appeared to bind to the outer membrane, explaining the loss of the barrier function. This property makes chitosan a potentially useful indirect antimicrobial for food protection. Analysis of surface topography by atomic force microscopy (AFM) showed a significant increase in roughness of all blends relative to chitosan. Observed antibacterial properties of chitosan could be primarily attributed to surface topographical changes.

Finally, both length and diameter of the microorganisms decreased after contact with chitosan.

Keywords: Atomic force microscopy; Chitosan; Antibacterial