Current progress in long-term and continuous cell metabolite detection using microfluidics

Cellular metabolism involves complex sequences of controlled biochemical reactions and many chemical compounds or metabolites. The quantification of these metabolites will provide information on the dynamic cellular metabolism and the effect of environmental conditions. There have been extensive studies in this field since the last few decades, including the recent developments in microfluidic-based technologies. The article aims to provide a review on the current microfluidic detection techniques for quantifying the levels of main metabolites, including glucose, lactate, pyruvate, dissolved oxygen, pH and reactive oxygen species, with a focus on continuous and/or long-term detections. Most of the current developments are towards single metabolite detection and single-point or short-time detection techniques. There is increasing effort in the detection of multiple metabolites in microfluidics with integrated cell culturing. The future developments should address several major challenges such as cell culturing, long-term and sensitive detection of multiple metabolites in the dynamic cell environment.