Vision-based cellular force measurement using an elastic microfabricated device

Manipulation and characterization of individual biological cells require cellular forces to be precisely measured in real time. This paper presents a computer vision-based cellular force measurement platform that allows for the use of a single vision sensor (CCD/CMOS camera) to simultaneously obtain two forms of feedback (i.e., vision and force). A novel silicone elastomer-based cell holding device and a sub-pixel visual tracking algorithm are developed. Deflections of elastic, low-stiffness structures are visually tracked, and material deflections are subsequently transformed into cellular forces. Experimental results demonstrate that the current vision-based force sensing system is capable of performing robust cellular force measurements at a full 30 Hz with a 3.7 mu N resolution. Importantly, the vision-based cellular force sensing framework established in this study is not scale- or cell-line-dependent. The device design, visual tracking algorithm, and experimental technique form a powerful framework that would permit visually resolving cellular forces in real time with a sub-nanoNewton (26 pN) resolution for applications in single cell manipulation and characterization.