Journal of Laboratory Automation 2015-02-01

Label-free measurements of reaction kinetics using a droplet-based optofluidic device.

Zhangming Mao, Feng Guo, Yuliang Xie, Yanhui Zhao, Michael Ian Lapsley, Lin Wang, John D Mai, Francesco Costanzo, Tony Jun Huang

Index: J. Lab. Autom. 20(1) , 17-24, (2015)

Full Text: HTML

Abstract

Label-free measurements of the reaction kinetics of a small sample volume are essential for efficient drug discovery, requiring methods and systems that are rapid, accurate, and cost-effective. Herein, we present an integrated optofluidic system for label-free characterization of reactions in a nanoliter reagent volume. This system contains a droplet-based microfluidic sampling section and an optical fiber-based spectroscopy detection section. By manipulating droplets containing reagents at certain concentrations at different times, quantifiable measurements via absorption spectroscopy can be made in a simple, sensitive, and high-throughput manner. We have demonstrated our system's capability by performing potency (IC50) assays of an inhibitor in a TEM-1 β-lactamase (enzyme) and nitrocefin (substrate) system. This integrated platform can potentially provide an automated, label-free, and low-cost method for many other assays of reaction kinetics. © 2014 Society for Laboratory Automation and Screening.