Comparing the Antibacterial Efficiency of Chitosan and Dextran as Nanocomposites against Escherichia Coli

Nanoparticles (NPs) are widely used in many different fields and applications. In this study, Silver (Ag) NPs and Titanium dioxide (TiO2) NPs were generated using the laser ablation method by using Q-switched Nd: YAG laser. In addition, Chitosan (CS) and Dextran nanopolymers were chosen to prepare the nanocomposites by combining the two types of nanopolymers with the generated NPs in different ratios to obtain the samples: CS and Dextran as a control, CS-Ag, CS-TiO2, CS Ag-TiO2, Dextran-Ag, Dextran-TiO2, and Dextran Ag-TiO2. Several tests were carried out on these nanocomposites such as Ultraviolet-Visual (UV-Vis) spectrometry and Atomic Mass Microscopy (AFM) tests. The antimicrobial efficiency of the prepared samples was obtained by testing their antibacterial activity against Escherichia coli (E. coli) thus the comparison between the two nanopoylmers was obtained. The AFM results showed that AgNPs and TiO2 NPs with sizes in the nanometer scale were generated from the laser ablation method. The UV-Vis results showed a reduction in the size of AgNPs when incorporated with CS and Dextran as well as a small reduction in TiO2 NPs size. The findings showed that the detectability of CS Ag-TiO2 had the largest inhibition zone when compared with all of the prepared samples proving that CS has a higher antibacterial activity against the E. coli bacterium than dextran nanocomposites as they showed larger bacterial inhibition zones. To sum up, CS is considered a promising biopolymer when incorporated with metallic NPs for E. coli bacterial inhibition.