Bionanocomposite of Au decorated MnO2 via in situ green synthesis route and antimicrobial activity evaluation

Green synthesis gaining a significant importance for the preparation of nanoparticles (NPs) and NPs-based biocomposites gained much attention in biological applications. In the current study, gold (Au) nanoparticles were prepared via green approach using cinnamon extract. The Au nanocomposite (NC) was prepared with MnO2 nanofiber mesh structure. The NC was characterized by XRD, SEM, FT-IR, EDX, UV–visible and DLS techniques. The MnO2 nanofibers diameter was in 10–25 nm range, which was arranged in a mesh form and Au NPs was combined with nanofibers randomly. The MnO2-Au NC antimicrobial activity was measured against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus strains. The antimicrobial activity of MnO2-Au NC was highly promising against tested microorganisms in comparison to control (ciprofloxacin, a standard drug). The antimicrobial activity of MnO2-Au NC was found in following order; > S. aureus > E. coli > P. aeruginosa with the zones inhibition of 22, 18 and 15 (mn), respectively. The MIC (minimum inhibitory concentration) values were 316, 342 and 231 (µg/mL) for E. coli, P. aeruginosa and S. aureus, respectively. In view of promising antimicrobial activity, the MnO2-Au NC prepared via green approach could have potential applications in medical field and future study can be engrossed on the biocompatibility evaluation of MnO2-Au NC using bioassays.