Preparation and characterization studies of chitosan encapsulated ZnO nanoparticles modified with folic acid and their antibacterial activity against selected bacterial species

This artic deals with the preparation of Chitosan (CS) coated Zinc Oxide (ZnO) nanoparticles modified with Folic Acid (FA) via the simple solvothermal method. The physicochemical properties were evaluated through characterization studies such as X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDAX), UV-Visible spectroscopy (UV-Vis), and Thermogravimetric and differential thermal analysis (TG/DTA). The crystalline size of the nanoparticles examined was 21.45 nm and 16.57 nm. The samples were subjected to antibacterial test (Gram-positive S. aureus, B. subtilis, and Gram-negative E. coli, P. aerugenosa) by the modified Kirby- Bauer well diffusion method and minimum inhibitory concentration (MIC) by using the broth dilution method in 96-well microtiter plate. This method was used to test the susceptibility of microorganisms. At high concentrations, CS-ZnO nanoparticles were found to have the highest zone of inhibition against S. aureus (20 mm) and B. subtilis (20 mm) and the lowest against E. coli (18 mm) and P. aeruginosa (10 mm). The MIC results were determined to be in the order CS-ZnO < FA-CS-ZnO. The zeta potential of nanoparticles was estimated to be -19.1 +/- 6.60 mV (CS-ZnO) and -29.3 +/- 5.56 mV (FA-CS-ZnO), respectively.