277956 Polymerization Amplification for Thermal Biodetection
Thermochemical sensors operate by monitoring the thermal energy change resulting from a chemical reaction and represent a simple, inexpensive and reliable method of monitoring a chemical reaction. Biosensors can be designed around thermochemical sensors through the specific biological binding of a critical reaction component to an immobilized phase, introducing the remaining reaction species to the immobilized reagent, and monitoring the temperature, which can be correlated to the concentration of the immobilized component. Most commonly, glucose oxidase is bound to an immobilized phase specifically in the presence of the target biomaterial. Subsequent exposure to an appropriate substrate solution drives a chemical process where a specific quantity of heat is liberated for each reaction in the enzymatic cycle. A sufficiently large change in thermal energy will alter the local temperature, and the temperature may be measured by a variety of reliable, proven methods. For this reason, thermal biosensors have been often promised as a simple, reliable analytical tool. Critically, the traditional, enzymatically-driven thermal biosensor is fundamentally limited by the net heat generated by glucose oxidase.
We describe the use of enzyme mediated polymerization to facilitate the sensitive, quantitative response to a biorecognition event. In this approach, glucose-oxidase is coupled to the target species though specific protein binding, and the enzyme participates in a reaction cascade yielding hydroxyl radicals. Enzyme kinetics dictate the timescale of polymerization, and ultimately enable the quantitation of the target species. The simplicity of the response enables simultaneous quantitation of multiple targets using inexpensive, off-the-shelf technology.