Microfluidic Chips for Characterization of Enzyme-catalyzed Reactions and Evaluation of Dose Responses for Drug Discovery

Abstract

In last century, the discovery of semiconductors, the invention of transistors and the creation of the integrated circuit brought a revolution in the field of computation, which marked the foundation of computers and information technology. In 21st century, miniaturization of size, integration of functions, and digitization of data is a global trend in every branch of technology. The chemical and biological laboratory technology is also witnessing booming trend towards miniaturization, integration, and digitization of laboratory experiments. The advantages of this trend include ultra-low reagent consumption, wide scope for parallelization and integration, increased reaction speed, and possibility of extreme portability. The ultimate goal of miniaturization, integration and digitization in chemical and biological laboratory technology is to automate all the reaction steps―reagent metering, concentration gradient generation, mixing, incubation and detection―with sub microliter-scale chip, which are popularly termed as lab-on-a-chip or µTAS (micro total analysis system). To address this ultimate goal, novel miniaturized, integrated and digitized chips are required in almost every field of biology, chemistry and biotechnology including cell biology, molecular biology, genomics, proteomics, enzyme kinetics, tissue engineering, stem cell engineering, and neurobiology. In this dissertation, we present invention and application of miniaturized integrated chips and technology for conducting enzyme-catalyzed assays. These chips rely on a novel microchannel and droplet based technology for the generation of concentration gradients with nano- and picoliter-scale sample volumes. The chips has inbuilt integration of sample metering, mixing, and detection steps involved in many biological and chemical experiments. This integration facilitates kinetic characterization and evaluation of dose response with single experiment. These chips could achieve simultaneous, parallel and independent reactions with nano- and picoliter-scale sample volumes, unlike its conventional tube and pipette-based and robotics-based methods. The present chips and technology is highly suitable for applications where the reagents or samples are highly expensive or limited in availability.