Optimization of Hard Protein Corona Isolation on Quantum Dots Using Dynamic Light Scattering and Zeta Potential Analysis

Abstract

The adsorption of biomolecules onto nanoparticle surfaces results in the formation of a protein corona, which governs the biological identity and fate of nanoparticles in physiological environments. Accurate isolation of the hard protein corona is essential for understanding nanoparticle–cell interactions and improving nanomedicine design. This study optimized experimental conditions for hard protein corona isolation from graphene and silicon-based quantum dots (QDs) using Dynamic Light Scattering (DLS) and zeta potential measurements. QDs were incubated with multiple biological media, including cancer cell culture media, patient-derived organoid (PDO) media, and serum-containing solutions for periods ranging from 1 to 24 h. Following incubation, protein-coated nanoparticles were isolated using gentle centrifugation and characterized by DLS to determine hydrodynamic diameter and surface charge. Increasing incubation time generally promoted protein adsorption, resulting in larger hydrodynamic diameters and reduced surface charge. The most stable corona was obtained after 6–12 h of incubation, whereas prolonged incubation beyond 12 h resulted in plateauing or slight reductions in particle size, suggesting protein exchange or aggregation. Graphene QDs exhibited more reproducible protein corona formation than silicon QDs, indicating that nanoparticle surface chemistry significantly influences corona evolution. The optimized protocol provides a reproducible strategy for isolating hard protein coronas suitable for downstream proteomic characterization and biological evaluation.