Background:
Fe3O4nanoparticles have great potential in different biomedical applications. Study of interaction of bare, and capped Fe3O4 nanoparticles with common blood proteins is a field of interest for understanding the underlying mechanism and biocompatibility.
Objective:
This work is aimed at studying the nature of binding of bare, citrate functionalised and bovine serum albumin coated Fe3O4 nanoparticles (Fe3O4NPs, CFe3O4NPs and BFe3O4NPs) with human hemoglobin (Hb), their instantaneous effect on amino acid group, heme group and secondary structure of Hb.
Methods:
Nanoparticles were prepared by chemical route and characterised by TEM, XRD and UV-Visible and FTIR spectroscopy. UV-Visible absorbance and fluorescence emission/excitation spectroscopy and circular dichroism were done to study the interaction of nanoparticles with Hb.
Results:
UV-Visible absorbance spectroscopy shows no blue or red shift of absorption peaks; Benesi-Hildebrand curves for amino acid band and soret band of Hb absorbance spectrum are straight lines with positive intercepts; apparent binding constants and Gibbs free energy change are within moderate level; they are larger for amino acid band in presence of CFe3O4NPs,larger for soret band in presence of Fe3O4NPs,and noticeably small for both bands in presence of BFe3O4NPs.Fluorescence emission/excitation spectra shows no noticeable shift of emission/excitation peak position of Hb in presence of the three nanoparticles. Multiple peak fitting, done for the L-peak of the excitation spectrum of Hb, shows major increase in the percentage of peak area of Tyr in presence of CFe3O4NPs.Circular dichroism measurement shows that CFe3O4NPs, Fe3O4NPs and BFe3O4NPs have reduced the α-helix content of Hb in decreasing order.
Conclusion:
Ground state complex formation of human hemoglobin with the studied nanoparticles with 1:1 stoichiometric ratio is suggested. Moreover, it is suggested thatCFe3O4NPsmay have stronger interaction with amino acid group while bare Fe3O4NPs may have stronger interaction with the heme group of Hb. Hindering of the energy transfer from tyrosine to tryptophan of Hb in presence of CFe3O4NPs is suggested. CFe3O4NPsmay also have some effect on the secondary structure of Hb as indicated through reduction of the α-helix content. BFe3O4NPshave shown very weak interaction with Hb in UV-Visible absorbance spectroscopy, fluorescence emission/excitation spectroscopy and circular dichroism experiment.
Investigation of the Kinetics of Photoinduced Electronic Transitions in Nanostructures of Bacterial Reaction Centers
