Date of Award

Spring 5-2020

Author's School

McKelvey School of Engineering

Author's Department

Biomedical Engineering

Degree Name

Master of Science (MS)

Degree Type



Arrhythmia is a common heart disease that happens when the heart is beating too fast, too slow, or irregularly. To study the mechanisms and treatments of this disease, it is important to acutely control the beating rate of the model as it will help distinguish the contribution of different potassium currents and drug-induced action potential in cardiomyocytes. The current method of tissue pacing, electrical pacing, causes contamination and corrosive damage to tissues, thus the tissues fail to be used repeatedly or in future studies. In this study, red-shifted channelrhodopsin (ReaChR) is applied as a non-chemical means to control the beating rate. ReaChR is a light-gated ion channel that opens and allows potassium to enter cardiomyocytes when excited by red lights. To deliver ReaChR into micro tissues, modified mRNA is chosen because of its higher transfection rate comparing to the plasmid, and lower cell toxicity comparing to the virus. Reducible polycation (RPC) is synthesized and used as transfection reagent to acquire a better transfection rate and modifiable structure. The results show successful modified mRNA synthesis and enhanced transfection efficiency with modified mRNA comparing to plasmid in both cells and tissues. The improved transfection efficiency of modified mRNA into iPSC-derived cardiomyocytes and iPSC- derived micro heart muscle using RPC is achieved. The results presented in this thesis demonstrate the potential of using modified mRNA to control the beating rate of the tissue and eventually control other physiological properties in cells.


English (en)


Nathaniel Huebsch

Committee Members

Jonathan Silva Stacey Rentschler


Permanent URL: https://doi.org/10.7936/0wrs-jt78

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Supplementary video 1

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Supplementary video 2