Nontechnical Abstract: Heart diseases are one of the leading causes of death in the US. Stem cellbased regenerative therapies are among the most promising treatment techniques. However, cells derived from stem cells are not uniform; only some percentage of the initial cell culture develops into the cell type of interest. Undifferentiated cells that remain within the cell population could lead to tumor. Furthermore, immature cells or cells with over-sensitivity would hinder the synchronous beating of the heart muscle cells, which can cause heart failure. Current methods to examine the purity of stem-cell based heart cells depend on cell surface markers, which is not a precise way to determine cellular functionality. This proposal offers a high-throughput screening technique to directly measure the functionality of differentiated heart muscle cells through their specific membrane potential changes during contraction. The proposed molecular-nanoplasmonic label-free voltage sensors will allow screening of single cell membrane potentials within confluent cell cultures and provide an accurate method for selecting and purifying functional cells from a mixed group. Development of such a precise technique would present a remarkable technological leap in stem cell-based research and strategies for cardiac regeneration. In addition to scientific and technological advancements, this research program will provide educational opportunities to underrepresented groups and minorities, and enhance involvement of undergraduate and graduate students in nanoscience and technology.
objective of this research proposal is to introduce ultrasensitive molecularplasmonic voltage probes for non-invasive, real-time and subcellular precision mapping of cardiac cell membrane potentials. These electrophysiological nanoprobes could have significant impact in differentiation of stem cell derived cardiac cells through massively parallel and precise mapping of single cell membrane potentials. Given the lack of experimental electrophysiological techniques with high spatial and temporal precision capabilities, this research program could significantly contribute to cardiac cell studies and regenerative therapies. The specific objectives of this research program are: (1) to develop molecular-plasmonic voltage sensors by using electromagnetic simulations, high throughput fabrication and chemical synthesis techniques, and optical/electrical characterization. (2) to realize real time and label free detection of tiny potential variations at diffraction limited spot sizes with microsecond temporal resolutions and high signal-to-noise ratios. (3) to achieve non-destructive imaging of single cells in large cell populations and distinguish individual cell characteristics in -cultured/multiple cell state.
The proposed research program involves theoretical understanding and numerical design of molecularplasmonic devices. Devices merging nano/micro-meter components will be fabricated using state of lithography and synthesis techniques. Fabricated devices will be tested using excitable cell populations with varying densities and cell compositions. Furthermore, changes in the membrane potentials of cardiomyocytes that are being differentiated from hiPSC will be measured in real-time.
