Title: Molecularly imprinted polymers as synthetic receptors for glucoronates, and their use for biochemical sensing.
Author: Nataliya MARCHYK
National thesis number: 2012COMP2053
- Molecular recognition is a fundamental process in biological systems. The creation of synthetic receptors mimicking the biological processes is of high importance in practical application due to their higher stability to harsh environments, long on-shelf life and application flexibility comparing to natural counterparts. Molecularly imprinted polymers (MIP) readily meet these conditions. MIPs are tailor-made synthetic receptors that are able to specifically recognize a certain target molecule. Their synthesis is based on the presence of a molecular template that directs the self-assembly of functional monomers around. In an excess of cross-linking agent the monomers copolymerize, and subsequent removal of the template molecule generates three-dimensional binding sites in the material that are complementary to the template in size, shape and position of the functional groups. Due to complexity of composition and various influencing factors, the rational design should be employed in order to improve the performance of MIP systems. Core-shell nanoparticles provide a unique possibility to incorporate agents with optical or magnetic properties into the core, providing broader possibilities for MIPs application, such as in bioimaging and monitoring. The work of the thesis is focused on development of MIPs for the specific recognition of glucuronates in aqueous environment with outlook for applicability in biological systems. The rational design framework included molecular modelling, spectroscopic analysis and the design of experiments. Molecular modelling simulated intermolecular interactions and allowed to discover the most promising analyte-monomer combinations which could be verified in situ via spectroscopic (NMR) method. The design of experiments with multi-objective optimization allowed finding the composition of MIP with the best performance to glucuronate as well as to understand the effects of influencing factors, compounds concentrations in particular, onto the MIP performance. Förster resonance energy transfer (FRET) was applied in order to evaluate the recognition event of the target analyte in the MIP system. Bearing in mind the application in biological systems, a new approach for the synthesis of core-shell nanoparticles was proposed. The principle is based on one-pot synthesis by conventional emulsion polymerization of iniferter seeds which serve as cores for final particles. The up-converting particles (UCPs) possess unique optical properties to absorb the light at higher wavelength and emit it at lower wavelength. That makes them very promising in bioimaging, since the autofluorescence of biological samples can be decreased significantly. A novel strategy was proposed to synthesize composite core-shell nanoparticles where UCPs were employed as the second local light source to initiate the polymerization from the particles’ surface.