Nanoscale Proteinosomes Fabricated by Self-Assembly of a Supramolecular Protein-Polymer Conjugate

Proteinosomes are a type of protein-based spherical capsules, which have potential applications in drug delivery, cell imaging, gene expression, and biocatalysis. In this research, a novel approach to the fabrication of proteinosomes entirely composed of protein molecules based on self-assembly of a supramolecular protein polymer conjugate is proposed. A supramolecular protein polymer conjugate was prepared by mixing beta CD-modified bovine serum albumin (BSA) and adamantane-terminated poly(N-isopropylamide) (Ad-PNIPAM) in aqueous solution. The BSA-PNIPAM bioconjugate self assembled into micelles with PNIPAM cores and BSA coronae at a temperature above the lower critical solution temperature (LCST) of PNIPAM. After cross-linking of BSA in the coronae, and followed by addition of excess beta CD, PNIPAM chains were cleaved from the micellar structures, and nanoscale proteinosomes were prepared. The dual-responsive proteinosomes dissociated in the presence of trypsin or glutathione.