In vitro evaluation of nanoantibiotics

Abstract

The discovery of antibiotics made a significant difference in human mortality by considerably reducing the number of deaths caused by infections. Over the years, the bacteria gradually developed resistance against available antibacterial agents, mainly due to the misuse and overuse of these agents. Nanoparticles, used as carriers for antibiotics, represent a promising approach of combating resistant bacteria. This study is focusing on assessing the antibacterial effects of nanoantibiotics specifically against planktonic Escherichia coli and Staphylococcus aureus biofilm. The nanoantibiotic structure used in this study is a nanocomposite that is a combination of different nanomaterial constructs in one particle. It includes a cerium oxide core as an antibacterial compound, mesoporous silica shell as a drug reservoir, capsaicin as an antibiotic drug molecule, and chitosan as an antibacterial coating. The effects of the nanoantibiotic and its constructs against planktonic strains of Escherichia coli were evaluated by using the Bioscreen C Microbiology Reader which is an automated microbiology growth curve analysis system. Furthermore, the permeability of the nanoantibiotic into Staphylococcus aureus biofilm was imaged by using confocal microscopy, and the effects of the nanoantibiotic against the biofilm were assessed by using the Resazurin cell viability assay. Comparatively, the in vitro evaluation results suggest that the nanoantibiotic inhibits Escherichia coli growth the most compared to its constructs separately, due to the combinatorial antibacterial activity of the nanocomposite structure. Moreover, the nanoantibiotic is permeating into the Staphylococcus aureus biofilm and inhibiting its growth. Further research can be conducted by loading antibacterial agents in this nanosystem and assess their effects.