Ipsita Chakravarty and Subir Kundu* Pages 707 - 718 ( 12 )
Background Multidrug-resistant pathogenic strain of Staphylococcus aureus is associated with hospital acquired infectious diseases. Due to the unselective use of antibiotics for a long time multidrug resistant bacteria and extensively drug-resistant, this is now posing a new challenge to the medical community.
Objectives The present study was focused on mycogenic synthesis of gold, silver and bimetallic gold and silver nanoparticles through bioreduction of noble metal salt using fungal biomass of Aspergillus niger NCIM 1025.
Methods An efficient approach for fungal growth was discussed wherein the biomass was cultivated under non-limiting conditions, followed by addition of gold salt, silver salt and bimetallic (Gold and silver) solution. The metal salt reduction efficacy was evaluated using Cyclic Voltammetry. Formation of nanoparticles was observed by visual color changes and confirmed by UV–visible characteristic peaks. The Mycosynthesized metallic and bimetallic nanoparticles were characterized by various advanced analytical methods and its antimicrobial activity was investigated against an MRSA strain associated with burn infections.
Results Formation of nanoparticles was observed by visual color changes and confirmed by UV–visible characteristic peaks. XRD spectra revealed crystalline nature of nanoparticles whereas TEM confirmed the presence of spherical nanoparticles. The bio fabricated nanoparticles were characterized using ICP-MS, XRD and TEM. UV-Visible spectrum of the gold, silver, bimetallic nanoparticles showed characteristic peak at 550nm, 450nm, and 480nm respectively. ICP-MS of the residual salt concentration depicted more than 75% percentage of bioconversion of metal salt to metal nanoparticles. TEM showed the formation of uniform, spherical monometallic nanoparticles. XRD results were in sync with the dynamic light scattering experiments which determined that the gold, silver, bimetallic nanoparticles ranged between 10-20 nm, 5-30nm, and 20-40nm respectively and were crystalline in nature with the face centered cubic symmetry.
Conclusions Topical gels were formulated using the synthesized nanoparticles and modern day antibiotic Daptomycin to combat burn infection. The synergistic Oligodynamic effect of topical gel containing nanoparticles along with Daptomycin showed enhanced antimicrobial activity against methicillin-resistant Staphylococcus aureus.
Topical gel, Drug resistance, Nanoparticles, Daptomycin, Fungi, Cyclic VoltammetrTopical gel, Cyclic Voltammetry
School of Biochemical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi - 221005, School of Biochemical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi - 221005