Fabrication of Silver Nanoparticles/Chitosan Nanofibers Composite Material Using a High-Pressure Wet-Type Jet Mill and Their Antibacterial Properties

Silver nanoparticles (NPs)/chitosan nanofibers (ChNF) composite material was fabricated using a high-pressure wet-type jet mill. A mixture comprising an aqueous silver nitrate solution and a ChNF suspension was prepared as a starting material. The mixture was then processed using the high-pressure wet-type jet mill at a discharge pressure of 100 MPa. X-ray diffraction analysis of the obtained samples revealed the presence of not only chitosan crystallites, but also silver metal crystallites. According to field-emission scanning electron microscopy observation, many nano-sized silver particles were immobilized and well-dispersed on the surface of ChNF. The silver NPs had a spherical shape with an average particle size of about 20 nm regardless of the number of jet milling cycles. The silver content in the composite materials increased slightly with the number of jet milling cycles. As a result of investigating the antibacterial properties of the silver NPs/ChNF composite material that is processed five times with the high-pressure wet-type jet mill at a discharge pressure of 100 MPa, it was found that the minimum inhibitory concentration (MIC) of that for E. coli was 4.2 mg/L, although raw ChNF had no antibacterial properties.[doi:10.2320/matertrans.MT-Z2022016]