Nanoscale probes for sensing molecular functions in live cells

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Project Summary / Abstract: This MIRA proposal merges two distinct projects supported by R01GM128142, “The role of membrane curvature in surface nanotopography-induced cell functions”, and R01GM125737, “Developing nanoscale electrophysiology sensors for robust intracellular recording”. While the two projects focus on different biological questions, the unifying theme is to develop nanoscale probes to elucidate the cellular machinery in the intricate environment of living cells. In this proposal, we discuss topics along the lines of the parent grants, focusing on the significance of the biological problems, our recent and evolving results, and directions for the future. For the first project, the long-term goal is to understand how membrane curvature regulates biochemical signals that are transmitted through the cell-matrix interface. At the cell-matrix interface, where the cells make physical contact with extracellular matrices, the membrane may be locally deformed by matrix topography or mechanical forces. As it remains a challenge to manipulate nanoscale membrane curvature in live cells, our current understanding of how local membrane curvature affects signal transmission is limited. We propose to use nanotechnology-based precision engineering to control interface membrane curvature in live cells. We seek to understand how cellular processes are affected by membrane curvature and the underlying molecular mechanisms. The knowledge gained will help us understanding how cells interact with extracellular matrix and also help us designing biomaterials for better integration with cells. For the second project, we are developing vertical nanoelectrodes into a robust and easy-to-use electrophysiology tool that can reliably achieve parallel intracellular recording of cardiomyocytes with minimal perturbation. Simultaneous nanoelectrode and patch clamp recordings on same cells confirmed that nanoelectrodes accurately record action potential waveforms for classification and characterization of stem-cell-derived cardiomyocytes. These nanoelectrodes will enable us to understand how in vitro interventions accelerate the maturation of stem-cell-derived cardiomyocyte. Furthermore, nanoelectrodes provide an ideal tool for monitoring the generation and resealing of membrane pores on cardiomyocytes that are prone to membrane rupture due to their large size and strong mechanical contraction. We will use nanoelectrode to investigate how proteins participate in the membrane resealing process. We hope to achieve a broad impact by combining the development of new tools with applications to specific biological systems.