Multi-channel potentiostate integrated with microfluidic channel for electrochemical real-time monitoring
Date
2017
Authors
Obeidat, Yusra M., author
Carnevale, Elaine, author
Chicco, Adam J., author
Chen, Thomas W., author
Journal Title
Journal ISSN
Volume Title
Abstract
This work describes the development of an integrated sensors system to measure concentrations of dissolved oxygen (DO), pH, glucose, and lactate concurrently at single cell level. DO was measured amperometrically using a three-electrode system of working (WE), counter (CE) and reference (RE) electrodes. pH was measured potentiometrically using two electrodes system of Indium Tin Oxide (ITO) WE and Ag/AgCl RE. Glucose and lactate were measured enzymatically by measuring the current generated from the oxidation of hydrogen peroxide generated from the catalysis of glucose or lactate at the WEs with their catalysis enzymes. A microfluidic chamber containing all four sensors was made using SU8 to investigate single oocytes/embryos immersed in up to 120 µL of respiration buffer. This work includes the results of using the integrated sensors system to measure the metabolic activities of real cells including single oocytes or embryos. The micro-chamber was completely sealed using top layer of ovoil and covered by top glass lid to avoid oxygen exchange between the inside of the chamber and the atmosphere, while being maintained at a temperature of 38.5 ºC to preserve cell viability. The oxygen consumption of cells, the lactate production and glucose consumptions were measured as a change in output current and converted to femto-mol (fmol) per second based on calibrations with buffer of known DO, lactate, and lactate concentrations. This integrated sensor system has some potential applications include evaluating effects of metabolic therapies on oocyte bioenergetics, study the effect of aging on embryos development and monitoring mitochondrial function throughout oocyte maturation and blastocyst development to predict embryo viability to compliment assisted reproductive technologies.