Abstract
An interesting nanoscale interfacial phenomenon mediated by gold nanoparticles (Au-NPs) was found, in that co-administration with Au-NPs enables percutaneous delivery of protein drugs. The Au-NPs with a mean size of 5 nm were revealed to be skin permeable, presumably due to the nano-bio interaction with skin lipids and the consequent induction of transient and reversible openings on the stratum corneum. Importantly, when simultaneously applied with Au-NPs, the protein drugs were also granted the ability to penetrate the skin barrier and migrate into the deep layers. This indicated that co-administration with the skin-permeable Au-NPs could mediate proteins across the skin barrier. Such co-delivery effect highlights a simple yet effective method for overcoming the skin barrier for percutaneous protein drug delivery. Employing this method, a non-invasive vaccine delivery strategy was developed, and by topically co-administrating antigens with Au-NPs, robust immune responses were elicited in the tested animals. The results provide the promise for achieving a needleless and self-administrable transcutaneous vaccination.