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Author ORCID Identifier

https://orcid.org/0000-0001-8608-6949

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Chemistry

Year Degree Awarded

2020

Month Degree Awarded

February

First Advisor

Sankaran Thayumanavan

Subject Categories

Organic Chemistry | Polymer Chemistry

Abstract

Discoveries at the interface of chemistry, biology, and materials science have emerged as a powerful route to impact life science in this century. My research in the Thayumanavan group is focused on problems at this interface. A common theme of all the six projects is the use of modern synthetic organic chemistry to build interesting, novel macromolecules which are chemically rich, to study the molecular self-assembly behavior in solution and then translate to solve problems in the biomedical area. By addressing the design challenge to prepare novel amphiphiles with desired functional groups, controlled molecular weight and the ability to respond to a broad range of stimuli, especially protein and enzyme, we have achieved the following aims that showed great potential for biomedical applications such as sensing, imaging, and drug delivery: a) we have systematically studied the molecular weight effects and hydrophilic-hydrophobic balance effects on enzyme induced supramolecular disassembly, which could provide tunability over covalent and non-covalent guest molecules release kinetics. b) Other than the single stimuli-responsive system, we outlined a simple and new strategy that was outlined for amphiphilic nanoassemblies to respond to a combination of intrinsic trigger protein and extrinsic trigger light in the logic gated fashion. c) Considering biomedical applications based on these nanoassemblies, we then try to solve the most critical step for nanomedicine, which is specifically targeting. Unlike common strategies relying on complementary ligands, we showed a cellular AND gate for highly selective cell accumulation by covalently masking and unmasking ligands on block copolymer-based nanogels, such an ability will facilitate tumor imaging and diagnostics; d) We then showed a self-immolative nanogel platform to deliver hydrophobic drugs, with accessible functional group present on the surface, this nanogel can be easily functionalized with various receptors for targeted delivery into cytosol and subcellular organelles; e) We designed a novel supramolecular approach that selectively transports water-soluble globular proteins from an aqueous phase to the water-pool of a reverse micelle in an apolar organic phase. Proteins can maintain functions after crossing an incompatible solvent interface, which opens new possibilities for the application of supramolecular assemblies in sensing, diagnostics, and catalysis. f) following these findings, we designed an enzyme nanoreactor for catalysis in apolar solvent and introduce crosslinks in the molecular assemblies, we will further try to control substrate permeability into the assembly to engineer unnatural selectivity in enzymes.

DOI

https://doi.org/10.7275/rrxr-hy34

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