Melanin-Mediated Synthesis of Silver Nanoparticles and Their Affinity Towards Tyrosinase

Resumo

The bacterial strain Pseudomonas sp. SSA has capacity to produce extracellular melanin that sequesters heavy metals. The brown-black melanin pigment was observed in the culture liquid and mediated synthesis of silver nanoparticles (AgNPs). The AgNPs were characterized using UV–visible, dynamic light scattering, energy dispersive X-ray, Fourier transform infrared and surface plasmon resonance spectroscopy, scanning electron and transmission electron microscopy and selected area electron diffraction analysis. The synthesized nanoparticles were found to be spherical in shape with size in the range of 14–30 nm and showed high antimicrobial activity against pathogenic bacteria and fungi. These nanoparticles revealed binding affinity towards fungal and human tyrosinases with K_D 4.601 × 10^–10 and 2.816 × 10^–5 M, respectively. In addition, produced nanoparticles did not show any toxic effect towards HeLa cells up to 20 μg/mL. These nanoparticles could find application in medicine and cosmetics due to their enzyme inhibition and antimicrobial activities.