AFM Microfluidic Cantilevers as Weight Sensors for Single Cell Mass Measurements

The inability to reliably measure small mass changes at the single-cell level has been a challenge in biological research. In this manuscript, we report the use of microfluidic cantilevers in liquid with picogram-scale weight sensing capability for the measurement of cellular mass changes of living single cells. With this instrumentation, we were able to perform fast mass measurements within 3 minutes. We show results of mass measurements of microspheres with errors within 100 picograms as well as single-cell mass measurements in a physiologically relevant environment. We also performed finite element analysis to simulate and optimize the structural design and materials of cantilevers. Our simulation results indicate that using polymer materials, such as SU8 and polyimide, could improve the minimal detectable mass by 3-fold compared to conventional silicon cantilevers. The simulations also suggest that smaller dimensions of length, width, and thickness would improve the mass detection capability of microfluidic cantilevers.