Stiffness Measurement of Organoids Using a Wide-Range Force Sensor Probe Fabricated Using a Quartz Crystal Resonator

The automation of the experimental process and evaluation method is required to screen chemical substances in the fields of biology and chemistry. In the case with biological evaluations, the automation of the mechanical probing has been considered, but the measurement method should possess versatility as the mechanical properties of biological samples widely distribute. We present a stiffness measurement using a quartz crystal resonator (QCR) fabricated force sensor probe. Owing to the low frequency noise, the QCR force sensor exhibits a wide force measurement range. We measured the stiffness of the two samples, organoids and polydimethylsiloxane (PDMS) beads, that have different Young's modulus. The fabricated QCR sensor probe exhibited the measurement range over five digits with the force resolution of 272 nN and the maximum load of over 30 mN. Using the sensor probe, the stiffness of organoids and PDMS beads was successfully evaluated; 2.51 kPa and 1.19 MPa, respectively. As a result, we succeeded in measuring the stiffness of various samples whose Young's modulus distributed over three digits.