Abstract

Microengineered Enzyme-based Biosensors for in-vivo and in-vitro Evaluations

Sara Talaei, Senior Researcher, Ecole Polytechnique Federale De Lausanne

Enzyme-based biosensors provide reliable, selective and fast analyte measurements. By applying microtechnology in development of these biosensors, high-throughput measurements with better accuracy and lower costs are achievable. Furthermore, miniaturized biosensors result in minimal tissue damage or infection in both in-vivo and in-vitro studies. We present design, fabrication and characterization of four different types of microengineered enzyme-based biosensors that have been developed recently in our laboratory. We describe these devices within two main categories of in-vivo and in-vitro biosensors. In each category, we introduce one device which is adapted for detecting higher concentrated metabolites (i.e. > 2 mM) such as glucose, and one which is adapted for lower concentrated metabolites (i.e. < 0.5 mM) such as glutamate neurotransmitter. The biosensors designed for in-vivo measurements are already tested for continuous real-time detection of subcutaneous glucose levels in human or glutamate levels in rat’s brain. We explain the function of various diffusion limiting and anti-interference strategies applied in these biosensors for more accurate measurements. The in-vitro biosensors are developed for continuous measurement of metabolites in cell-cultures. We describe how by employing microfluidic techniques in these biosensors, the linear response range, sensitivity and limit of detection can be adjusted.