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Cancer cells overexpressing folate receptors have been targeted using a folate decorated carriers for anti-cancer drugs in aims to overcome the tissue non-specificity of anti-cancer agents. We here prepared magnetic nanoparticles and surface-decorated them with different amounts of folate to optimize the number of the immobilized folate on the carriers for superior targeting effects. Magnetic nanoparticles were prepared by oxidizing ferric or ferrous chloride solution to iron oxide in the presence of poly(vinyl alcohol). The magnetic nanoparticles were functionalized with primary amines for subsequent reactions with the different feed ratios of the activated folate. The magnetization degree of the folate magnetic magnetization were slightly decreased when the folate on the particles were increased. Intracellular uptakes of the nanoparticles were shown to be increased and become saturated dependent on the amounts of the surface-immobilized folate. The folate-decorated magnetic nanoparticles showed negligible cytotoxicity against KB cells from 5 μg to 35 μg of the nanoparticle weights.

Nanofibrous matrix was fabricated for the purpose of obtaining bi-phasic protein releases from a single protein delivery system. A block copolymer composed of poly(ethylene glycol) and poly(epsilon-caprolactone) was co-electrospun with protein solutions through a dual nozzle electrospinning system. Surface-exposed amine groups of the protein-encapsulating nanofiber at an aqueous phase were chemically conjugated to the carboxyl groups of another protein for surface-immobilization. The surface-immobilized proteins and the core-encapsulated proteins in the nanofibers were characterized by scanning electron microscopy and confocal microscopy. Encapsulation efficiency of protein in the core of the nanofiber was increased when poly(vinyl alcohol) was mixed in the protein solution. Flow rate ratios of protein solutions to polymeric solutions significantly affected encapsulation efficiency of proteins in the nanofiber, where high flow rate ratios increased encapsulation efficiencies of proteins in the nanofiber. Release profiles of the immobilized proteins and the encapsulated proteins from the nanofiber were examined for 4 days. The encapsulated proteins showed initial burst profiles while the surface-immobilized proteins showed no or minimal release of proteins for the release period. Thus, the nano-inspired fibrous matrix can be potentially employed to fabricate a drug delivery device with a bi-phasic release profile of proteins.