An ultra-sensitive micro sensor for biophysical studies of single cells cultured in 3D extracellular matrix

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Considerable experimental evidence acquired during the last three decades has now established that living cells are contractile. They generate force on 3D tissues or 2D substrates. Forces and matrix stiffness have a profound influence on a wide range of cell behavior such as growth, motility, and differentiation. More recently, it is appreciated that cells not only respond to these cues from their 3D matrix, but also remodel the matrix and hence influence the subsequent cues. Cancer cells exploit such reciprocity within the tumor to support their metastatic journey. The precise role of mechanics in determining this reciprocity remains elusive. For example, how cells transduce mechanical cues into biochemical processes and vice versa. Which processes are involved in remodeling the matrix? Probing these fundamental questions need experimental platforms that allow to evaluate cell-forces in a 3D matrix and quantify the key parameters that determine the cell-matrix dynamics. Methods to measure single cell forces on 2D have been advanced over the last three decades. Currently, there is no method available to measure cell forces in 3D. Centennial High School (Champaign) drama teacher will assist in developing a drama with high school students representing cancer development where characters will represent cancer, fibroblast and immune cells. The scenes will mimic various stages of cancer. Research will be integrated with education through involvement of undergraduate students from minorities in research, and web dissemination. The PI has a long record of outreach activities, including multiple videos series development for students and public. The goal of this project is to close this gap. It will design, develop and test an ultra-sensitive (~10nN/um) micro force sensor that allows to quantify single cell force, dynamics, and extra-cellular matrix remodeling in 3D matrix. The sensor will be applied to quantify force generation and matrix remodeling by fibroblasts, and to explore force-dependent cross talk between cancer and stromal cells leading to metastatic progression. The sensor consists of two grids, one connected to a soft spring and the other to a rigid support. A droplet of liquid cell-matrix (e.g., collagen) mixture is dispensed on the grids. It fills the grids due to capillarity and forms a free-standing tissue bridging between them. The tissue contains one or a discrete number of cells depending on the questions to be addressed. The cell(s) forms adhesion with the matrix and generates force, which is sensed by the spring. The extra cellular matrix stiffness can also be obtained by the sensor by stretching the matrix. The sensor will be used to study single fibroblasts in 3D collagen for their force, dynamics and matrix remodeling. Finally, the interactions between cancer cells and cancer associated fibroblasts in 3D matrix and the role of forces on the interaction will be explored. The outreach activities will include developing a drama with high school students representing cancer development where characters will represent cancer, fibroblast and immune cells. The scenes will mimic various stages of cancer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.