Apolipoprotein E-enriched protein corona enhances the blood-brain barrier transport of β-sheet-breaker peptide-functionalized gold nanoparticles.

The transient, heterogeneous nano-bio interface defined by the protein corona in biological environments dictates the biodistribution, immune recognition, metabolism, and clearance of nanomaterials. Far from being a drawback, this corona can be harnessed for targeted nanodrug delivery when its composition is predictably tuned or deliberately modulated. We hypothesized that preloading apolipoprotein E (ApoE), previously identified as a constituent of the corona of β-sheet-breaker peptide-functionalized gold nanoparticles (AuNPs), would enhance transport across the blood-brain barrier (BBB) and increase brain uptake. To test this, we synthesized AuNPs (approximately 12 nm) functionalized (AuNP-f) with CLPFFD or THRPPMWSPVWPCLPFFD peptides, both containing the β-sheet-breaker motif LPFFD, which recognizes β-amyloid aggregates implicated in Alzheimer's disease. After incubation with human plasma, hard-corona proteins were profiled by 2D IEF/SDS-PAGE and LC-MS/MS. Proteins were ranked based on their roles in nanoparticle trafficking and BBB transcytosis, and ApoE was selected for deliberate enrichment due to its recurrent presence. ApoE-decorated AuNP-f were evaluated in an in vitro BBB model and in vivo biodistribution assays using Sprague-Dawley rats. Brain accumulation was assessed ex vivo. Preloading ApoE onto AuNP-f significantly enhanced nanoparticle transport across the BBB in vitro and increased brain accumulation in rats. These results demonstrate that rational corona enrichment with ApoE improves BBB transit and brain accumulation without altering nanoparticle surface chemistry. Corona engineering thus offers a pragmatic route to brain-targeted nanodrug delivery and may be extended to other protein-receptor axes for organ-specific targeting.