Enzyme delivery using protein-stabilizing and cell-penetrating 30Kc19α protein nanoparticles

Nanoparticles (NPs) are an emerging strategy for drug delivery and have been studied for the delivery of various biomolecules, such as chemically synthesized drugs and therapeutic proteins. In particular, protein NPs are non-cytotoxic and biodegradable. Application of a full length recombinant 30Kc19 protein to human serum albumin (HSA) NPs has been shown to improve the cellular uptake and stability of the cargo enzyme. In this study, we demonstrate that drug delivery can be achieved with only the alpha-helix domain of the 30Kc19 protein (30Kc19 alpha), and without the addition of HSA. Protein concentration and pH were crucial for NP generation. NPs had a uniformly spherical shape with an optimal diameter of 180-230 nm, and released beta-galactosidase in a sustained manner. The 30Kcl9 alpha protein provided stability to the cargo enzyme, and helped maintain the specific activity of the enzyme. X-gal staining showed effective delivery of D-galactosidase into human dermal fibroblasts. Non-cytotoxic property of the 30Kcl9 alpha protein demonstrates that such NPs could be a resourceful tool for delivering drugs to cells.