Interaction of Metal-Based Nanoparticles with Proteins: Relation to Structure, Function and Amyloid Forming Propensity of Lysozyme and α-Lactalbumin

Abstract

Metal nanoparticles (NPs) such as gold (AuNP), silver (AgNP), and zinc oxide (ZnONP) demonstrate variety of applications including drug delivery, imaging, nanomedicine, and sensing. However, many of their applications involve biological systems, which might trigger their interaction with various biomolecules such as proteins. Proteins are highly sensitive to various stresses and ligand interaction due to the intimate correlation of their structure with biological function. Moreover, it is also a well-known fact that protein misfolding and aggregation process is the prime cause of a number of neurodegenerative disorders like Alzheimer’s disease, Parkinson disease, Prion disease, etc. The interaction of NP with the proteins can cause the change of structure as well as the function of proteins and can generate a new identity such as ‘nanoparticle-protein’ complex.
Here, in our present study, we investigated the interaction of two small homologous proteins: bovine α-lactalbumin (BLA) and hen egg white lysozyme (HEWL) with three different nanoparticles (AuNP, AgNP, ZnONP) in vitro. The structure, function, stability and amyloid forming propensity of the proteins were studied during the interaction with three different NPs using various spectroscopic and microscopic techniques. We synthesized NPs by chemical as well as semi-green methods using non-toxic materials such as starch, PEG, and NaOH with precursor salts with a size of below 20 nm. Moreover, we synthesized the self-assembly of ZnONP of an average size of 163 nm. The NPs were further characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) as well as dynamic light scattering (DLS) zeta sizer for the analysis of size and shape and stability of NP.....