Serum proteins on nanoparticles: early stages of the "protein corona"

• Published in: Nanoscale Vol. 13; no. 48; pp. 255 - 2563
• Main Authors: McColman, Sarah, Li, Rui, Osman, Selena, Bishop, Amanda, Wilkie, Kathleen P, Cramb, David T
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 16.12.2021
• Subjects: Binding; Biomolecules; Cadmium selenides; Cross correlation; Energy transfer; Fluorescence; Heterogeneity; Monolayers; Nanoparticles; Polystyrene resins; Polystyrenes; Protein Corona; Proteins; Quantum Dots; Serum albumin; Serum Albumin, Bovine; Serum proteins
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d1nr06137b

Nanoparticles in biological systems such as the bloodstream are exposed to a complex solution of biomolecules. A "corona" monolayer of proteins has historically been thought to form on nanoparticles upon introduction into such environments. To examine the first steps of protein binding, Fluorescence Correlation/Cross Correlation Spectroscopy and Fluorescence Resonance Energy Transfer were used to directly analyze four different nanoparticle systems. CdSe/ZnS core/shell quantum dots, 100 nm diameter polystyrene fluospheres, 200 nm diameter polystyrene fluospheres, and 200 nm diameter PEG-grafted DOTAP liposomes were studied with respect to serum protein binding, using bovine serum albumin as a model. Surface heterogeneity is found to be a key factor in protein binding to these nanoparticles, and as such we present a novel conceptualization of the early hard corona as low-ratio, non-uniform binding rather than a uniform monolayer. Nanoparticles are studied with respect to serum albumin binding using a direct and quantitative approach. We find that protein binding saturation occurs at sub-monolayer surface coverage and attribute binding to surface chemistry heterogeneity.