Metal doped silica nanohybrids with extensive bacterial coverage for antibacterial applications exhibit synergistic...

Nanotechnology has triumphantly overcome several barriers that have formed in modern life. Bacterial infections are a critical public health issue. They emphasized the failure of conventional treatments, high mortality and morbidity rates, antibiotic resistance, and other factors leading to the development of novel and affordable antibacterial medications. In this study, three types of metals (Ag, Cu, and Co) were doped separately into a silanol network in silica nanoparticles. The synthesized monometallic nanohybrids were combined in equal proportions to formulate bi and trimetallic nanohybrids. They were characterized structurally and morphologically. Fourier transform infrared (FTIR) and Raman spectroscopy studies were used to investigate the formation of the bonds and the pertinent peak positions. X-ray diffractograms (XRD) validated the crystalline structures of the metal nanohybrids. X-ray photoelectron spectroscopic study (XPS) confirmed the successful addition of metals to the silanol network. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images were used to characterize the morphology of nanohybrids and demonstrate their dimensions are on the nanoscale. The fraction of each metal doped in the silanol network was determined using energy dispersive spectroscopy (EDS) and atomic absorption spectrometry (AAS). To assess activity and confirm antibacterial synergy, the antibacterial activity of all synthesized nanohybrids was examined. The minimum inhibitory concentration-MIC (Ranged from 12.25 to 1560.00 μg/mL), minimum bactericidal concentration-MBC (Ranged from 197.00 to 3125.00 μg/mL), IC₅₀ values (Ranged from 30.56 to 1683.00 μg/mL-) and fractional inhibitory concentration index (FICI) were determined and compared. Well diffusion assay was conducted against both ATCC cultures and clinical samples of gram-positive bacteria; Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 49619), MRSA (ATCC 33591) and gram-negative bacteria; Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC BAA 1706) and Pseudomonas aeruginosa (ATCC 27853). The highest synergistic radical scavenging performance of trimetallic nanohybrid (90.67 ± 0.095 %) was established by the DPPH (2,2 diphenyl-1-picrylhydrazil) experiment. Finally, when compared to monometallic nanohybrids, it was demonstrated that the synthesized multimetallic nanohybrids have a substantial potential as an emerging and cost-effective antibacterial agent.