Protein Coronas Derived from Cerebrospinal Fluid Enhance the Interactions Between Nanoparticles and Brain Cells

Neuronanomedicine harnesses nanoparticle technology for the treatment of neurological disorders. An unavoidable consequence of nanoparticle delivery to biological systems is the formation of a protein corona on the nanoparticle surface. Despite the well-established influence of the protein corona on nanoparticle behavior and fate, as well as FDA approval of neuro-targeted nanotherapeutics, the effect of a physiologically relevant protein corona on nanoparticle-brain cell interactions is insufficiently explored. Indeed, less than 1% of protein corona studies have investigated protein coronas formed in cerebrospinal fluid (CSF), the fluid surrounding the brain. Herein, we utilize two clinically relevant polymeric nanoparticles (PLGA and PLGA-PEG) to evaluate the formation of serum and CSF protein coronas. LC-MS analysis revealed distinct protein compositions, with selective enrichment/depletion profiles. Following incubation with brain cells, serum and CSF coronas on PLGA particles showed enhanced associations with all cell types as compared to their corresponding corona on PLGA-PEG particles. CSF-derived protein coronas on PLGA nanoparticles, specifically, showed the greatest nanoparticle-cell interactions, with Pearsons correlation analysis revealing that proteins associated with enhanced nanoparticle-cell interactions were exclusively enriched in this protein corona. This study demonstrates the importance of correct choice of physiologically relevant biological fluids, and its influence on the formation of the protein corona, subsequent nanoparticle-cell interactions.