Cellular dynamics of bovine aortic smooth muscle cells measured using MEMS force sensors

Abstract

Adhesive cells perceive the mechanical properties of the substrates to which they adhere, adjusting their cellular mechanical forces according to their biological characteristics. This mechanical interaction subsequently affects the growth, locomotion, and differentiation of the cell. However, little is known about the detailed mechanism that underlies this interaction between adherent cells and substrates because dynamically measuring mechanical phenomena is difficult. Here, we utilize microelectromechamical systems force sensors that can measure cellular traction forces with high temporal resolution (~2.5 µs) over long periods (~3 h). We found that the cellular dynamics reflected physical phenomena with time scales from milliseconds to hours, which contradicts the idea that cellular motion is slow. A single focal adhesion (FA) generates an average force of 7 nN, which disappears in ms via the action of trypsin-ethylenediaminetetraacetic acid. The force-changing rate obtained from our measurements suggests that the time required for an FA to decompose was nearly proportional to the force acting on the FA.

MEMS-Based Pulse Wave Sensor Utilizing a Piezoresistive Cantilever

“…Two electrodes were placed at the roots of the two hinges and the resistance of the cantilever is defined as the resistance between the two electrodes. The fabrication process of the cantilever can be found in previous studies [24][25][26][27][28][29]. A photograph of the fabricated sensor chip attached and wire-bonded to a flexible substrate and a photograph of the cantilever are shown in Figure 2a.…”

“…A differential pressure in the range of ±10 Pa was applied to the cantilever using a pressure generator. The fractional resistance change of the cantilever was measured using the setup reported in previous studies [24][25][26][27][28][29][30][31][32], which consists of the Wheatstone bridge circuit and an amplifying circuit whose output is recorded using a ScopeCorder (Yokogawa Test & Measurement Co., Tokyo, Japan, DL850). The calibration result in Figure 2c shows the linear relationship between the differential pressure and the fractional resistance change of the cantilever.…”

Bubble entrapment during the recoil of an impacting droplet

“…The sensor used in this study was a MEMS-based piezoresistive cantilever, similar to the sensors that have been developed in our previous studies to measure forces generated by droplets and cells [23][24][25][26][27][28][29] . The cantilever was fabricated from a silicon-on-insulator wafer, whose device Si, box, and handle Si layers' thicknesses were 300 nm, 400 nm, and 300 μm, respectively.…”

Temperature Dependence of the Beating Frequency of hiPSC-CMs Using a MEMS Force Sensor

“…We used MEMS-based cantilever force sensors to investigate how the beating frequency of hiPSC-CMs changes with temperature. The use of silicon-based force sensors for studying cellular forces has advantages in terms of temporal resolution [ 18 , 19 , 20 , 30 , 31 ]. Silicon-based force sensors have temporal resolutions in the order of GHz, and it has been reported that the force can be measured in units of adhesive spots on cells because of their high measurement speed of 400 kHz [ 31 ].…”

“…The use of silicon-based force sensors for studying cellular forces has advantages in terms of temporal resolution [ 18 , 19 , 20 , 30 , 31 ]. Silicon-based force sensors have temporal resolutions in the order of GHz, and it has been reported that the force can be measured in units of adhesive spots on cells because of their high measurement speed of 400 kHz [ 31 ]. The present study was based on these previous studies, and the kHz-order sampling rate enabled the accurate detection of the timing of the beats.…”