Hitting the target with bifunctional phage

Protein-based nanomedicine platforms for drug delivery

Protein-based nanomedicine platforms for drug delivery comprise naturally self-assembled protein subunits of the same protein or a combination of proteins making up a complete system. They are ideal for drug-delivery platforms due to their biocompatibility and biodegradability coupled with low toxicity. A variety of proteins have been used and characterized for drug-delivery systems, including the ferritin/apoferritin protein cage, plant-derived viral capsids, the small Heat shock protein (sHsp) cage, albumin, soy and whey protein, collagen, and gelatin. There are many different types and shapes that have been prepared to deliver drug molecules using protein-based platforms, including various protein cages, microspheres, nanoparticles, hydrogels, films, minirods, and minipellets. The protein cage is the most newly developed biomaterial for drug delivery and therapeutic applications. The uniform size, multifunctionality, and biodegradability push it to the frontier of drug delivery. In this Review, the recent strategic development of drug delivery is discussed with emphasis on polymer-based, especially protein-based, nanomedicine platforms for drug delivery. The advantages and disadvantages are also discussed for each type of protein-based drug-delivery system.

Melanoma and lymphocyte cell-specific targeting incorporated into a heat shock protein cage architecture

Protein cages, including viral capsids, ferritins, and heat shock proteins (Hsps), can serve as nanocontainers for biomedical applications. They are genetically and chemically malleable platforms, with potential as therapeutic and imaging agent delivery systems. Here, both genetic and chemical strategies were used to impart cell-specific targeting to the Hsp cage from Methanococcus jannaschii. A tumor vasculature targeting peptide was incorporated onto the exterior surface of the Hsp cage. This protein cage bound to alpha(v)beta(3) integrin-expressing cells. Cellular tropism was also imparted by conjugating anti-CD4 antibodies to the exterior of Hsp cages. These Ab-Hsp cage conjugates specifically bound to CD4(+) cells. Protein cages have the potential to simultaneously incorporate multiple functionalities, including cell-specific targeting, imaging, and therapeutic agent delivery. We demonstrate the simultaneous incorporation of two functionalities, imaging and cell-specific targeting, onto the Hsp protein cage.