Development of micropost force sensor array with culture experiments for determination of cell traction forces

Abstract

Cell traction forces (CTFs) are critical for cell motility and cell shape maintenance. As such, they play a fundamental role in many biological processes such as angiogenesis, embryogenesis, inflammation, and wound healing. To determine CTFs at the sub-cellular level with high sensitivity, we have developed high density micropost force sensor array (MFSA), which consists of an array of vertically standing poly(dimethylsiloxane) (PDMS) microposts, 2 microm in diameter and 6 microm in height, with a center-to-center distance of 4 microm. In combination with new image analysis algorithms, the MFSA can achieve a spatial resolution of 40 nm and a force sensitivity of 0.5 nN. Culture experiments with various types of cells showed that this MFSA technology can effectively determine CTFs of cells with different sizes and traction force magnitudes.

Quantifying the Traction Force of a Single Cell by Aligned Silicon Nanowire Array

“…As a result, the accuracy of the measured force may be limited by two factors, one being the density of the microposts and the other the resolution of the optical measurement technique adopted. [22][23][24] Silicon nanowires (Si-NWs) have been demonstrated as unique probes for quantifying biological processes at a high spatial resolution. An integration of arrays of field effect transistors made using Si-NWs and the neuron system by Lieber presents a breakthrough approach for studying electrical signal transmissions in neuron and biological species.…”

Review of cellular mechanotransduction on micropost substrates

“…To address these limitations and better depict traction force distribution, researchers have developed micropost arrays with high spatial resolution and broad application [46,157]. The rapid development of techniques makes it possible for engineering mechanical properties of substrates through precise and highly repeatable fabrication processes [87,131,144,157]. The introduction of micropost arrays to isolate and quantify the exerting forces at individual adhesion sites is a breakthrough in addressing limitations of preceding traditional substrates.…”

“…With the advance of micro-and nanotechnology, various micropost arrays as listed in Table 1 have been developed to characterize traction forces of different types of cells [45,87,131,157]. Generally, the measurement accuracy of traction force mainly depends on two factors: the aspect ratio and micropost density under the same optical measurement techniques [33,87,139].…”

“…the relationship between the applied force and micropost deflection is nonlinear, in which finite element method (FEM) is used for micropost calibration [27,87]. In addition, the strain energy, u(i), stored in individual posts, is calculated to better depict and quantify cytoskeletal contractility [180], where x(i) denotes the displacement of ith post versus original position.…”

Equibiaxial Mechano-Elastic Strain on Osteblasts: Theoretical Considerations

“…59 CTFs, as a result, are implicated in numerous biological processes such as wound healing, embryogenesis, angiogenesis, and inflammation. 60 An advanced insight into how CTFs are regulated and transmitted to the ECM will, therefore, be important in understanding the physiological and pathological processes in organs and tissues. …”