Assessment of extracellular matrix modulation of cell traction force by using silicon nanowire array

Extracellular matrix (ECM) has critical influence on cell adhesion and force generation, and has been wildly used in tissue engineering scaffolds to promote cell growth and function. A uniform, precise and densified silicon nanowires (Si-NW) array was fabricated to investigate the dynamics of cell traction force (CTF) modulated by ECM at submicron spatial resolution. The CTF result suggested that the time slot from 6 h to 24 h was critical for fibronectin to enhance CTF generation. Fibronectin also increased the formation of the cellular membrane-bound focal adhesion (FA), and the enhancement pattern of CTF and FA due to fibronectin modulation were highly similar. Meanwhile, the trends of CTF and FA dynamics in either the fibronectin modified or the bare Si-NW array were coordinated with each other, respectively. These results identified that the consistency of FA formation and CTF generation lasted for as long as dozens of hours. In addition, the effective modulation slot of the external ECM was within 36 h, revealing the existence of a balanced time point for the self-secreted ECM to pull up with the externally added ECM after the cells started to grow on the scaffolds. The influence of data sampling on CTF measurement was also evaluated. This investigation provides important information for the understanding of the CTF derivation dynamics and the design of ECM modified tissue engineering scaffolds.