On-chip measurement of pH using a microcantilever: a biomimetic design approach

In vitro organ models used for drug discovery and delivery must recapitulate actual physiological parameters, including pH, for more reliable results. Monitoring pH is both important and challenging in many processes. At the scale of physiological environments of microfluidic organ chip models, additional fluctuations in pH can lead to organ dysfunction and there are natural mechanisms to control this. In this work, a microfluidic pH sensor-embedded chip was designed to monitor pH that can be connected to the main organ-on-chip culture. The mechanism consists of separation and sensing with a buffer system that is also found in the cell cytoplasm, so it is a biomimetic approach. The deflection of the pH-sensing cantilever was improved by applying finite element methods to obtain better sensitivity and wider detection range for different concentrations of hydrogen ions in the buffer reaction chamber.