Chip-Based Heat Stimulation for Modulating Signal Propagation in HL-1 Cell Networks

Signal propagation in cardiac cell networks can be modulated by heat stimulation. Here, the response of a connected HL-1 cardiomyocyte cell network to the application of confined heat stimuli using Ca²⁺ imaging is investigated. Localized temperature gradients are generated by resistive heating via microwire arrays on a chip surface, which serves as a substrate for growing a confluent cell network. It is demonstrated that upon heat stimulation, the velocity of the propagating Ca²⁺ wave in the network is locally increased, leading to a deformation of the wavefront. Furthermore, evidence of a change in the signal propagation direction caused by a relocation of the pacemaker cell is shown. This effect might be used in future applications, where heat is employed as an alternative modality for cell stimulation protocols.