Antibacterial activity of silver nanoparticles (AgNP) confined to mesostructured silica against methicillin-resistant Staphylococcus aureus (MRSA)

Prosthetic joint infection (PJI) is one of the main factors that causes joint replacement surgery failure, of which hip joint infection is the most serious. Staphylococcus aureus accounts for more than 50% of the infections caused by pathogenic microorganisms. Unfortunately, antibiotics have long been used to kill bacteria, but increasingly, multiple drug resistant pathogens (MDRP), such as methicillin-resistant Staphylococcus aureus (MRSA), have appeared and are causing a significant reduction in the efficacy of traditional antibiotics. In this study, silver nanoparticles (AgNP) confined to mesostructured silica (MS-Ag) powders were prepared to evaluate their antibacterial activity against MRSA. According to the results of thermogravimetric analysis (TGA), there was no weight loss when the temperature was greater than 600 degrees C. This result showed that the water, alcohol, non-ionic surfactant F127 and PUF in the silicone-containing colloid were completely removed. These results indicated that the calcination temperature for total dehydration was at least 600 degrees C. The as-synthesized precursor samples of MS-Ag1 were calcined directly at 400 degrees C, 500 degrees C, 550 degrees C and 600 degrees C for 2 h. The specific surface area increased over the range of 400-500 degrees C, and the non-ionic surfactant F127 and PUF were removed over this temperature range. Further, a transition occurred from an amorphous state to a crystalline state, and the thickness of the pore wall increased with the increasing calcination temperature over the range of 500-600 degrees C. Thus, the specific surface area and pore volume decreased from 526.7 m(2)/g and 0.84 cm(3)/g to 384.7 m(2)/g and 0.67 cm(3)/g, respectively. The antibacterial activity of MS-Ag powders against MRSA was verified by the disk diffusion method and time-killing curves. The minimum inhibitory concentrations (MIC) of the MS-Ag powders against MRSA were between 2.5 mg/mL and 5 mg/mL. (C) 2018 Elsevier B.V. All rights reserved.