Tumor-specific hybrid polyhydroxybutyrate nanoparticle: surface modification of nanoparticle by enzymatically synthesized functional block copolymer.

A new approach to functionalize the surface of hydrophobic nanocarrier through enzymatic polymerization was demonstrated. The effective coupling between the hydrophobic surface of PHB nanoparticle and PHB chain grown from the enzyme fused with a specific ligand provided a simple way of functionalizing nanoparticles with active protein layers in aqueous environment. PHB nanoparticles loaded with model drug molecule, Nile red, were prepared through oil-in-water emulsion solvent evaporation method and the surface of nanoparticles were functionalized with tumor-specific ligand, RGD4C, fused with PHA synthase that drove the coupling reaction. The functionalized PHB nanoparticles showed a specific affinity to MDA-MB 231 breast cancer cells indicating that the tumor-specific ligand, RGD4C, was effectively displayed on the surface of PHB nanoparticles through enzymatic modification and confers targeting capability on the drug carrier.