Optically Controlled Oscillators in an Engineered Bioelectric Tissue

• Main Authors: Harold M. McNamara, Hongkang Zhang, Christopher A. Werley, Adam E. Cohen
• Format: Article
• Language: English
• Published: American Physical Society 2016-07-01
• Series: Physical Review X
• Online Access: http://doi.org/10.1103/PhysRevX.6.031001

Complex electrical dynamics in excitable tissues occur throughout biology, but the roles of individual ion channels can be difficult to determine due to the complex nonlinear interactions in native tissue. Here, we ask whether we can engineer a tissue capable of basic information storage and processing, where all functional components are known and well understood. We develop a cell line with four transgenic components: two to enable collective propagation of electrical waves and two to enable optical perturbation and optical readout of membrane potential. We pattern the cell growth to define simple cellular ring oscillators that run stably for >2  h (∼10^{4}  cycles) and that can store data encoded in the direction of electrical circulation. Using patterned optogenetic stimulation, we probe the biophysical attributes of this synthetic excitable tissue in detail, including dispersion relations, curvature-dependent wave front propagation, electrotonic coupling, and boundary effects. We then apply the biophysical characterization to develop an optically reconfigurable bioelectric oscillator. These results demonstrate the feasibility of engineering bioelectric tissues capable of complex information processing with optical input and output.