Effect of structure in ionized albumin – based nanoparticle: Characterisation, Emodin interaction, and in vitro cytotoxicity

Abstract

A γ-irradiated bovine albumin serum based nanoparticle was characterised structurally, and functionally. The nanoparticle was characterised by A.F.M, D.L.S, zeta potential, T.E.M., gelelectrophoresis, spectroscopy (UV-Vis, Fluorescence, FT-IR, and CD). Its stability was studied under adverse experimental conditions: pH values, chaotropic agents, and ionic strength and stability studies against time were mainly carried out by fluorescence spectroscopy following the changes in the tryptophan environment in the nanoparticle. Its function was studied by the interaction of the NP with the hydrophobic drug Emodin was studied. The binding and kinetic properties of the obtained complex were tested by biophysical methods as well as its toxicity in tumour cells.According to its biophysics, the nanoparticle is a spherical nanosized vehicle with a hydrodynamic diameter of 70 nm. Data obtained describe the nanoparticle alone as nontoxic for cancer cell lines. When combined with Emodin, the bioconjugate proved to be more active on MCF-7 and PC-3 cancer cell lines than the nanoparticle alone. No haemolytic activity was found when tested against ex vivo red blood cells. The stability of the albumin nanoparticle is based on a competition between short-range attraction forces and long-range repulsion forces. The nanoparticle showed similar behaviour as albumin against pH while improving its stability in urea and tween 80. It was stable up to 15 days and presented no protein degradation in solutions up to 2 M salt concentration. Significantly, the albumin aggregate preserves the main activity-function of albumin and improved characteristics as an excellent carrier of molecules.