Probiotic bacteria Bacillus licheniformis mediated sustainable green synthesis of nanoparticles and its multifaceted mechanisms to control dermal pathogens

Abstract

Nanotechnology is advancing at a remarkable pace, has gained significant attention for its applications in healthcare, especially through the development of nanoparticles with unique physicochemical properties. Among various metal nanoparticles, silver nanoparticles (AgNPs) have emerged as potent agents due to their broad-spectrum antimicrobial, anti-inflammatory, and wound-healing properties. The research emphasizes a sustainable approach to synthesize nanoparticles by using probiotic bacteria Bacillus licheniformis (BlNps) and to evaluate their potential in dermatophytic fungal pathogens, especially for acne treatment. The synthesis of BlNps was confirmed using UV–Visible spectroscopy, with peak observed at 430 nm. Additional characterizations were performed using Dynamic Light Scattering (DLS), Zeta Potential analysis, Fourier Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and X-ray Diffraction (XRD). Dynamic light scattering (DLS) analysis showed an average particle size of 255.0 nm with the zeta potential value of −20.8 mV. XRD analysis confirmed FCC crystalline framework of BlNps. FESEM results confirmed the predominant presence of spherical shaped nanoparticles with small proportion of polymorphs with the size ranging between 30 and 50 nm confirming the synthesis of nanosized particles. EDAX analysis confirms the presence of silver. Toxicity assessment was performed in zebrafish to determine the biocompatibility and safety of the nanoparticles and confirms a dose-dependent toxic effect in zebrafish embryos. Antifungal efficacy of BlNps was examined by treating two dermatophytic fungi, namely Microsporum canis and Trichophyton rubrum strains with the synthesized nanoparticles. Results revealed a significant reduction in fungal growth, with inhibition rates of 68 % and 69 % for strain 1 and strain 2 at concentration of 250 μg/ml, respectively. Antibacterial efficacy was examined in Staphylococcus aureus strains and results revealed a strong growth inhibition at 25 μg/ml and 12.5 μg/ml of BlNps. These findings suggest that probiotic bacteria mediated BlNps hold promising potential for safe and effective dermal applications, particularly for the control of skin infections caused by microbes.