J. Zheng, H. Yang, A. Strandberg, W. Ireland, D.J. Needleman, J.J. Vlassak
Harvard University,
United States
Keywords: picowatt microfluidic calorimetry, metabolic heat measurement, fast antimicrobial susceptibility testing, single-cell analysis
Summary:
Advances in diagnostic and analytical technologies are essential to address challenges in fields such as microbiology, developmental biology, and biophysics. Calorimetry, the measurement of heat flow, has long been a powerful tool for studying biological and chemical systems, but its sensitivity and applicability to small-scale and dynamic processes have been limited. We present a hybrid micromachined calorimetry device with a resolution on the order of tens of picoWatts, enabling the direct measurement of both fast and long-term processes. This breakthrough allows us to quantify metabolic rates in small cell populations, large single cells, embryos, and even extremely subtle heat fluxes with unparalleled precision. The platform’s exceptional sensitivity and compact design integrate microfluidic channels with advanced calorimetric sensors, requiring only 80 nL of sample volume. Its real-time, non-invasive measurement capability provides critical insights into biological and chemical systems. One of the key applications is antimicrobial susceptibility testing (AST), where the device reduces diagnostic time from days to hours by detecting metabolic heat from as few as 32 bacterial cells. Additionally, the platform’s versatility extends to monitoring chemical reactions, metabolic activity in single embryos, and energetic propagations in biophysical systems. Its ability to measure heat fluxes in a wide range of processes makes it an invaluable tool for both fundamental research and applied science. This microfluidic calorimetry technology offers unparalleled precision and versatility, opening new avenues for understanding and analyzing complex biological and physical phenomena.