Functionalised and core-shell molecularly imprinted polymer (MIP) nanoparticles for sensor development / Exploiting Dormant Radical Chemistry

Functionalised and core-shell molecularly imprinted polymer (MIP) nanoparticles for sensor development:
Molecular imprinting is the technique of imparting molecular recognition properties in a cross-linked synthetic polymer by polymerisation in the presence of a molecular template.1 The resultant materials are known as molecularly imprinted polymers (MIPs) and have applications in separations, assays, sensors and catalysis and are often referred to as “plastic antibodies”. For diagnostic applications preparation of the materials as nanoparticles (nanoMIPs) have many advantages, as they can be used as direct replacements for antibodies in existing device formats.2 We have recently pioneered a solid phase approach to the synthesis of nanoMIPs which is compatible with automation3 and allows the surface of the particles to be modified with a variety of functional coatings.4
Project Aim: In this project it is proposed to prepare surface-modified nanoMIPs and investigate their utility in the production of electrochemical sensors and assays. A starting point will be the synthesis of nanoparticles grafted with precursors of conductive polymers (polyaniline or polythiophene) to produce nanoparticles with conductive coating following oxidation to the conductive material. A displacement or capture-based assay could then be performed on an interdigitated electrode, monitoring changes in conduction as a function of nanoparticle density at the electrode surface. These or similar particles will also be investigated for their potential for electrochemically-triggered capture or release or as novel colorimetric labels in assays. We will also assess their utility as sensing layers and determine whether the layers can be built-up by electrochemical deposition of the precursor particles.
The candidate will receive training in modern methods of organic and polymer synthesis, molecular imprinting, nanoparticle characterisation, electrochemistry, sensor development and the use of biosensor platforms such as QCM and Biacore.

Exploiting Dormant Radical Chemistry:
Dormant radicals (DRs) are kinetically stable free radical species that have much longer lifetimes than “normal” free radicals due to their highly delocalised and/or sterically hindered nature. Examples include dialkyldithiocarbamate radicals, triphenylmethyl radicals and nitroxy radicals (such as TEMPO). DRs are relatively unreactive to vinyl groups and H-abstraction, with their chemistry being dominated by radical recombination reactions. This feature of their chemistry has led to their use as capping species in “living” free radical polymerisation reactions; as photoiniferters (dialkyldithiocarbamate esters) and as reversible thermal initiators (nitroxide-mediated polymerisation).
Project Aim: The aim of the project is to exploit the chemistry of dormant radical species in new polymer forming reactions in solution and in the solid state. This includes the formation of novel polymer architectures, cyclo-polymer formation and an investigation of dormant radicals as potential catalysts.
The project has the potential to develop new routes to novel polymer architectures, initiation regimes, molecular recognitions systems and catalysts and will involve training in organic synthesis, photochemistry, polymer chemistry and polymer characterisation.

We are an equal opportunities employer and particularly welcome applications for Ph.D. places from women, minority ethnic and other under-represented groups.