Studies toward (i) a depolymerizable poly(vinylcarbamate) and (ii) a turn-off fluorescent sensor for β-D-galactosidase

Open Access
Author:
Kaweesi, Henry
Graduate Program:
Chemistry
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
September 26, 2013
Committee Members:
  • Scott T Phillips, Thesis Advisor/Co-Advisor
Keywords:
  • depolymerization
  • poly(carbamates)
  • stimulus responsive end-cap
  • fluorescence
  • turn-off sensor
  • anthracene diboronic acid
Abstract:
Poly(carbamates) that depolymerize from head-to-tail through azaquinone methide intermediates show slow rates of depolymerization, particularly in non-polar solvents. Previous research in the Phillips group has demonstrated that the rate of depolymerization can be increased by reducing the aromaticity of the repeating unit, a feat accomplished by replacing the benzene repeating units with naphthalene or phenanthracene repeating units or by tuning the electronics of the benzene repeating units by attaching a methoxy substituent to the benzene ring. Despite this progress, the challenge still remains to develop thermally-, acid- and base-stable polymers that degrade in the solid state (a non-polar environment) in response to a specific stimulus that removes the protective end-cap on the terminus of the polymer. This thesis describes a single unit model system of a depolymerizable poly(carbamate) that rapidly and selectively degrades through a vinylogous spacer after removal of an end-cap that responds to base. Furthermore, the thesis describes progress toward a dimeric model and a polymeric unit. The second part of this thesis describes a turn-off fluorescent sensor for an enzymatic biomarker. We hypothesized that in the context of resource-limited environments, a turn-off fluorescence sensor would more easily distinguish low quantities of analytes than turn-on sensors when low-cost fluorescence readers are used for the assay.