Hydrophilic Quaternary Trimethyl Chitosan Stabilized Silver Nanoparticles: Synthesis, Characterization and Antimicrobial Activity.

Abstract

Antimicrobial resistance (AMR) endangers the effective management of an increasing range of bacterial and fungal infections, alternative antimicrobial drugs are thus, expedient. In this study, Quaternary Trimethyl Chitosan (QTMC) was prepared by improved two step reductive methylation of Chitosan (CTS) employed as a capping agent for the synthesis of silver nanoparticles (QTMC-AgNPs). The hydrophilic QTMC and QTMC-AgNPs were characterized using various analytical and spectroscopic techniques. The Proton Nuclear Magnetic Resonance ( 1 HNMR) was used to determine the degree of quaternization (DQ) and degree of dimethylation (DT) of QTMC as 63.33 and 11.75 % respectively. The Ultraviolet-Visible (Uv-Vis), Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR), X-ray Diffraction (XRD), Energy Dispersive X-ray (EDS) and X-ray Photoelectron (XPS) Spectroscopic results evidently indicated high degree of quaternization of CTS and configured QTMC-AgNPs. Thermogravimetric Analysis/Derivative Thermogravimetry (TGA/DTG) were used to study the decomposition process of QTMC and QTMC-AgNPs. The surface morphological difference of QTMC and QTMC-AgNPs was explored via Scanning Electron and High-Resolution Transmission Electron Microscopies (SEM and HR-TEM) whereas particle size distribution was analyzed using Dynamic Light Scattering. Furthermore, HR-TEM indicated QTMC stabilized AgNPs with average nanoparticulate size of 10 nm while DLS revealed 12.5 nm. This well-tailored QTMC-AgNPs exhibited strong antibacterial and antifungal activities against the tested bacteria and fungi infections.