Fabrication, characterization and application of the novel bionanomaterials

This dissertation focuses on developing methods to synthesize novel bionanomaterials, studying their properties and exploring their potential applications. Fabricating semiconducting nanowires is a significant challenge in making nanoscale electronic devices. We propose to use self-assembling biomolecules as templates for the fabrication of nanowires. Here we demonstrate that quantum dots (QDs) could be conjugated to actin filaments, forming long semiconductor filaments. We constructed an optical system and developed the interactive software for fluorescence anisotropy imaging of single QDs and QD-nanowires. The fluorescence anisotropy studies revealed that QD transition dipoles are likely circular (elliptical) dipoles. The fluorescence anisotropy of a single QD is stable and depends mostly on the 3-dimensional orientation of the QD. Furthermore, QDs have a preferable orientation in actin-based nanowires. Secondly, we are developing a novel nanotechnology platform for tumor imaging and therapy, which is based on the discovery of a water soluble peptide—pHLIP (pH Low Insertion Peptide). pHLIP can be used for targeting acidic solid tumors due to its spontaneous pH-dependent insertion in cellular membrane. We synthesized several pHLIP constructs by conjugating pHLIP N-terminus to near-infrared dyes (NIR-pHLIP), quantum dots (QD-pHLIP), gold nanoparticles (Nanogold-pHLIP) and single-walled carbon nanotubes (SWCN-pHLIP), and investigated the efficiency of pHLIP to selectively deliver such imaging or therapeutic agents to tumors established in mice. We demonstrated the excellent tumor targeting abilities of these constructs, except QD¯pHLIP, which were cleared quickly from blood and accumulated in lymphatic nodes. In brief, this work opens new ways to develop and use novel bionanomaterials in the fields of bionanoelectronics and nanomedicines