A new sensor for bacteria using binding or specific degradation of stimuli responsive polymers

The project will investigate the use of a smart polymer for the detection of bacteria. The underlying principle of this work is that the binding of the chain ends of the hyperbranched polymers can be used to attach the polymer to the cell surface of bacteria. In some cases this binding can progress the polymer through a critical conformational change, in which the polymer changes, in aqueous soloution, from an open solvated coil to a tight non-solvated globule. In other instances the conformational change can be brought about after binding by a small temperature change. Furthermore, careful design of the chain-end ligand can be used to ensure that binding can be formulated to be specific to individual sites on different species of bacteria,. The change from open coil to tight globule can be detected by monitoring fluoresence from chemical labels situated on the polymer chain . These labels report on the chain's conformation by a change in fluoresence. The project will investigate the use of both soluble polymers, which could be added to a wound bed as a method of detecting the presence of bacteria and also immobilized hydrogel materials. The latter might be used as active wound dressings. In another version of this technology hyperbranched polymers will be synthesized to have peptide chain ends that can be degraded by specific extracelluar proteases. In this instance, the polymers will detect the bacteria following degradation of the end groups, which will expose polar carboxylic end groups. Thus, these systems will progress from a tight non-solvated globule to an open solvated chain in the presence of the target bacteria. In brief, we propose to develop novel polymer technology to rapidly detect bacteria with an easily observed optical signal.