Bio-inspired synthesis of multi-functional nanomaterials for drug delivery and imaging application

Abstract

Surface-engineered magnetite nanocrystals have been emphasized for their uses for contrast agents for magnetic resonance image (MRI). However, numerous complications in reaction such as harsh reaction conditions, toxicity of reactants and products, and high possibility of agglomeration during reaction greatly limit the number of materials, approaches and applications. Herein, we report a simple and biologically compatible reaction of mono-disperse and robust coating of hyaluronic acid (HA), naturally occurring polysaccharide, on magnetic nanocrystal surface using dopamine as an anchor. Dopamine, an analog of the unusual amino acid 3,4-dihydroxy-L-phenylalanine (DOPA) in mussel adhesive protein, was conjugated onto hyaluronic acid (HA-DN). Magnetic nanocrystals stabilized in aqueous solution by cetyltrimethylammonium bromide (CTAB) was simply mixed with HA-DN in aqueous solution to form mono-disperse coating on nanocrystals (HA-DN/MNC) followed by purification using centrifugation. AFM and TEM images clearly demonstrated the mono-disperse coating of HA-DN/MNC. HA-DN/MNC exhibited superparamagnetism and great stability in aqueous solution and buffer solution for a long period of time. HA-DN/MNC showed enhanced cellular uptake to CD44 over-expressed cells via HA-CD44 interaction revealed by prussian blue assay and MRI imaging. Diverse applications of metallic nanomaterials are highly dependent on the finely tuned modulation of their electric, optical, magnetic, and fluorescent properties. Precise control of their assembly and organization has been a major challenge to attain desired properties that can be hardly achieved from single nanoparticles and disorganized macroscale aggregations. Until recently, however, methods for nanoparticle assembly have been restricted to a narrow range of nanoparticles because they have required specific environmental factors or sophisticated nanoparticle surface chemistry. Herein we present a bio-inspired generalized approach to ...