I present applications of imaging and spectroscopy to understand mechanical, chemical, and electrical dynamics in biological materials. The first part describes the development and characterization of a protein-based fluorescent calcium and voltage indicator (CaViar). The far-red fluorescence of CaViar faithfully tracks the cardiac action potential in cardiomyocytes. CaViar's green fluorescence reports the resulting calcium transients. I demonstrated the applicability of CaViar in vivo with transgenic zebrafish designed to express CaViar in their hearts. Spinning disk confocal imaging allowed detailed three-dimensional mapping of simultaneous voltage and calcium dynamics throughout the heart of zebrafish embryos, in vivo, as a function of developmental stage. I tested the effect of channel blockers on voltage and calcium dynamics and discovered a chamber-specific transition from a calcium-dependent to a sodium-dependent action potential. I also describe a new measurement technique using a fluorescent voltage indicator to report absolute voltage via the indicator's temporal response. / Physics
| Identifer | oai:union.ndltd.org:harvard.edu/oai:dash.harvard.edu:1/11744434 |
| Date | 04 February 2015 |
| Creators | Hou, Jennifer Hsin-I |
| Contributors | Cohen, Adam Ezra |
| Publisher | Harvard University |
| Source Sets | Harvard University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Rights | open |
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