A microfluidic platform for glucose sensing using broadband ultrasound spectroscopy

This paper reports, for the first time, a method for characterizing liquid samples in a microfluidic device using continuous wave broadband ultrasound spectroscopy. An analytical model to predict the transmission response of the device is developed along with an experimental setup which is constructed to validate the model over a set of length scales. Experiments are then conducted to characterize various liquid samples, including glucose-water solutions, contained within the milli-cavity devices using contact type ultrasound transducers (with center frequency 15 MHz). An algorithm to process the measured response to calculate the speed of sound in the liquid channel by filtering the total response with those of the intermediate layers is developed. The models and experimental results show that is possible to utilize this relatively simple and non-contact ultrasound interrogation technique for quantifying the concentration of chemical analytes in liquid samples.