Study of Physical Interactions of Silver Nanoparticles with Human Insulin for its Diabetes Related Wound Healing Activity

Abstract

Green synthesis of AgNPs was done at pH 7.4 by aqueous extract of tulsi leaves (TAE) under sunlight. Thereafter insulin coating of the AgNPs were done by incubating with recombinant human insulin at physiological conditions (temperature 37⁰C and pH 7.4) for an hour. The physical interactions of AgNPs with insulin was studied by using UV-visible spectroscopy, Dynamic Light Scattering (DLS), Zeta potential measurement, Tyrosine intrinsic fluorescence, far UV Circular Dichroism (far UV-CD), Fourier Transform Infrared spectroscopy (FTIR), Raman spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and Transmission electron microscope (TEM). The Thermodynamic kinetics was studied from time and concentration dependent fluorescence spectra shows the reaction was most favourable at 37⁰C with ΔG -7.48 kcal/mole and ΔS 0.76 kcal/mole K-1 indicates that the reaction is endothermic with activation energy 3.84 Kcal mole-1and rate constant 604,500 s-1. The wound healing activity was checked out by cell migration of lung epithelial cell line in presence of 3.0 pM and 60 pM insulin protected AgNPs (IAgNPs), in media containing different glucose concentration (100, 180 and 360 mg/dl), shows the effective migration takes place in the presence of nanoparticles and after 24 hours the cell culture containing 60 pM IAgNPs healed up completely.