Inhibition of Amyloid Fibrillation of Bovine Serum Albumin by Zinc Oxide Nanoparticles

Protein fibrillation is associated with different disorders, and nanomaterials had been used for the inhibition of amyloid fibrillation. In the present work, inhibition of fibrillation of bovine serum albumin (BSA) was targeted by zinc oxide nanoparticles (ZnONPs). BSA fibrils were made by incubating the protein at 65°C at pH 7.4. Inhibition of fibrillation was studied using fluorescence-based techniques like thioflavin T (ThT) assay, intrinsic tryptophan fluorescence, and ANS fluorescence assay along with transmission electron microscopy. The fluorescence intensity of ThT was enhanced by the addition of BSA fibrils. But when protein fibrils (made in the presence of ZnONPs) were added to ThT, the fluorescence intensity of ThT was decreased. This suggests the inhibition of BSA fibrillation by ZnONPs. Maximum inhibition was achieved at a 5μM concentration of ZnONPs. Kinetic studies based on ThT fluorescence confirmed the inhibition of BSA fibrillation by ZnONPs. Tryptophan and ANS fluorescence studies indicate that the nanoparticles did not cause significant changes in the microenvironment of the Trp residues and the surface hydrophobicity, respectively. TEM images support the inhibition of BSA fibrillation by ZnONPs.