Enhanced antibacterial activity of pulsed laser-synthesized silver and gold nanoparticles combined with methylene blue.

The photosensitizing synthesizing agents are crucial against multidrug-resistant bacteria and treating tumors. In this study, silver nanoparticles (Ag NPs) and gold nanoparticles (Au NPs) were synthesized by pulsed laser ablation in different mediums. Later, methylene blue (MB) were attached each nanoparticle to improve their antimicrobial efficiency. Ag and Au NPs with different sizes were obtained and their characterization were performed using transmission electron microscopy (TEM), UV-vis, and photoluminescence spectra. The cytotoxicity measurement was also performed using different cell lines. The average size distribution of Ag NPs in citrate, PVP, and PVA at 1064 nm was discovered to be 6 nm, 10 nm, and 12 nm, respectively. The Au NPs with 6 nm size were obtained with picosecond laser pulses. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were both deactivated using these Ag NPs in combination with MB. MB and Ag NPs combination showed stronger antibacterial activity due to higher singlet oxygen generation and deactivated the entire 10^8 CFU/mL concentrated S. aureus and E. coli bacteria within 6 minutes of the 660 nm LED irradiation period. The use of MB/Ag NPs in PDT may be useful in treating cancer in vivo, infections of prosthetic joints, open wounds with bacterial pathogens, and tumors. the ongoing study on the laser ablation synthesis of Au NPs and its efficacy as an antimicrobial agent with methylene blue against different strains of bacteria will also be presented.