DESIGN OF HYBRID POLYMER- INORGANIC NANOASSEMBLIES FOR BIOMEDICAL APPLICATIONS

Abstract

Assembly of inorganic nanoparticles (NPs) can give rise to novel collective properties due to the coupling between adjacent subunits, which are not accessible from individual nanoparticles. Among them, hybrid polymer-inorganic nanoassemblies (HPINs) are particularly attractive by combining the complementary strengths of inorganic NPs and polymers. This dissertation describes the design of HPINs with elaborately tailored physicochemical properties and the applications of HPINs in tumor diagnosis and therapy.

First, we introduced the design principles and representative morphologies of HPINs. Size, shape, surface charge and coatings are crucial properties to be considered before the design of HPINs. Among various types of HPINs, we focused on the hybrid vesicles assembled from polymer-tethered inorganic NPs due to their synergistic properties that surpass their constituent components. We also summarized recent advances in the development of HPINs as attractive platforms for cancer imaging and therapy.

Second, we developed an enzyme-free signal amplification technique, based on gold vesicles encapsulated with Pd−Ir NPs as peroxidase mimics, for colorimetric assay of disease biomarkers with significantly enhanced sensitivity.

Third, we introduced a universal approach to attach amphiphilic block copolymers onto oleic acid or/and oleylamine capped NPs to trigger their assembly. Various NPs including Fe3O4, Cu9S5, MnO and upconversion NPs were assembled into hollow vesicles with novel physicochemical properties for a variety of biomedical applications.

Finally, we described the fabrication of nanosized magneto-vesicles comprising tunable layers of densely packed superparamagnetic iron oxide nanoparticles (SPIONs) in membranes via cooperative assembly of polymer-tethered SPIONs and free poly(styrene)-b-poly(acrylic acid). Due to the high packing density of SPIONs, the magneto-vesicles showed enhanced signal in magnetic resonance imaging as well as improved efficiency in magnetic-guided drug delivery both in vitro and in vivo.