Morphological and biophysical insights into the gold nanorods binding interaction of haemoglobin/myoglobin by hybrid spectroscopic approaches with bacterial cytotoxicity evaluation

Abstract

Great attempts have been noticed on the examination and invention of nano bioconjugates owing to prospective uses in various areas such as biocatalysis, biosensors, bioanalytical science, biofuel cells and protein supported nanodevices. An essential feature of our insightful of bionanoconjugates was to quantitatively distinguish how biomacromolecules interface with nanostructured materials. In this paper, bovine haemoglobin (BHb)/equine skeletal myoglobin (EMb) and gold nanorods (AuNRs) are chosen for the investigation of nanostructured materials and biomacromolecules interaction. Absorption spectroscopy, high resolution transmission electron microscope (HR-TEM) together with Zeta potential measurements were first explored for the morphological changes of AuNRs-BHb/EMb interactions. Absorption spectral profiles and molecular docking results of AuNRs with BHb/EMb were clearly suggesting that BHb/EMb molecules adsorbed on the surface of AuNRs. Then, biophysical interaction and conformational changes of BHb/EMb with AuNRs were investigated by using hybrid spectroscopic approaches. Fluorescence nature of BHb/EMb is drastically quenched after the successive addition of AuNRs. This binding interactions of BHb/EMb followed static quenching process. Absorption, FT-IR, synchronous emission, three dimensional emission and red edge excitation shift (REES) studies were applied to investigate the conformational changes of BHb/EMb with AuNRs. In addition, AuNRs and its bionanoconjugates were further evaluated for the bacterial cells of B. subtilis and E. coli.