Single Cell Functional Analysis via Drop-Screen
Precision medicine refers to giving the right therapeutics, to the right patient, at the right time. In the context of cancer, successful implementation of precision medicine, requires treatment individualization not only taking into account patient and tumor factors, but also tumor heterogeneity and tumor evolution over time. In this study, a continuous flow microfluidic device was developed as a functional flow cytometer (Drop-Screen) to detect secreted multiplexed protease activities at single cell resolution. The individual cells from patient samples are encapsulated within water-in-oil droplets for single cell multiplexed protease assay. We modified FRET (fluorescence resonance energy transfer)-based substrates to accommodate different fluorescent pairs with distinct excitation and emission wavelengths to obtain multiple signals from droplets containing single cells. Four substrate-protease reactions in a droplet were simultaneously monitored at three distinct pairs of fluorescent excitation (UV: 400nm, B: 470nm, G: 546nm, R: 635nm) and emission (B: 520nm, G: 580nm, R: 670nm) wavelengths. To infer a quantitative profile of multiple proteolytic activities from single cells, we applied the computational method Proteolytic Activity Matrix Analysis (PrAMA). The capability to determine multiple protease activities at single cell resolution has the potential to characterize tumor progress of individual patients for therapeutics.
Dr. Chia-Hung Chen is an Assistant Professor at National University of Singapore (NUS). Before joining NUS, he worked at Massachusetts Institute of Technology as a postdoctoral associate. He received his Ph.D. degree at the University of Cambridge (Biological and Soft Systems). He earned his M.S. degree at Harvard University (Division of Engineering and Applied Science) and earned his B.S. at National Taiwan University (Physics). Dr. Chen is developing a research program focused on integrative microfluidic platforms for functional assay, single cell analysis and cell mimetic smart hydrogel system manufacturing for biomedical applications. Compared with most current fluidic devices using gene sequence for diagnosis, microfluidic functional assay offers unique advantage in rapid measurement to characterize biological fluids for on-time precision medicine. For example, an intelligent microfluidic system that integrated imaging technology, multiplexed chemical sensors and a computational data-analysis method was developed to analyze small amounts of physiological samples to determine the disease progression of individual patients with cancer. With this program, Dr. Chen has delivered promising research outcomes, including 46 papers in international journals including Nature Communications, PNAS, JACS, Lab on a Chip, Advanced Materials, Advanced Functional Materials, Small, Biosensors and Bioelectronics, and Analytical Chemistry. Moreover he has collaborated with clinicians/researchers at the National University Hospital of Singapore (NUHS) and Massachusetts General Hospital (MGH) to develop droplet device. One of my projects is now sponsored by an industrial partner, MediaTek and aims to develop a wearable microfluidic sensor for personal healthcare at home. Moreover, he has secured the external grants of amount more than 4M USD as Principle Investigator (PI) to support his research activities until end of 2022 and was nominated by Royal Society of Chemistry (RSC) committee, as an Emerging Investigator in Lab on a Chip.