AAV capsid-based nanocarriers encapsulating inorganic nanoparticles for targeted delivery.

Current nanoparticle (NP) delivery systems often suffer from off-target accumulation and limited intrinsic targeting capabilities, restricting their biomedical applications. Here, we present a strategy to assemble adeno-associated virus (AAV) capsid proteins around inorganic nanoparticles to generate viral protein nanocarriers (VPNCs) with preserved targeting functionality. AAV capsid protein VP3 is recombinantly expressed in Escherichia coli (E. coli), purified under denaturing conditions, and refolded via a controlled dialysis process. Direct NP addition results in heterogeneous protein corona formation and increased aggregation. In contrast, delayed NP incorporation during partial VP3 refolding significantly improves particle homogeneity, reduces aggregation, and yields more uniform protein coatings. This optimized approach is successfully applied to gold NPs and quantum dots, demonstrating its versatility across NP systems. Furthermore, substitution of AAV2 VP3 with the brain-targeting AAV.CAP-B10 variant in VPNCs enables Ly6a-dependent delivery of NPs in engineered HEK 293T cells and primary hippocampal neurons. Together, these findings establish VPNCs as a modular platform for delivering NPs with AAV-derived targeting specificity.