Poster T15 - High throughput multi-modal screening platform for 3D engineered heart tissues

Introduction: Three dimensional engineered heart tissues (3D EHTs) have become indispensable as in vitro models to assess drug cardiotoxicity, a leading cause of failure in pharmaceutical development. A current bottleneck is the relatively low throughput and limited modalities of assays that measure spontaneous contractile forces exerted by millimeter-scale EHTs typically recorded through precise optical measurement of deflection of the polymer scaffolds that support them. To address these issues, we have developed an all-optical system that assesses the contractile and electrophysiological functions simultaneously in the high throughput 96-well format. The synchronized monitoring of excitation-contraction behaviors in will improve predictivity and reliability of EHT as a preclinical cardiotoxicity screening model, help refine, reduce, and replace the use of animal or human subjects.

Materials and

Methods: The described high throughput cardiotoxicity assay encompasses three challenges: an optical challenge to acquire high resolution images of 96 EHTs, a programing challenge to process 96 sets of contractile and electrophysiological data, and an engineering challenge to allow long-term electrical pacing of 96 EHTs.

For the optical challenge, the required resolution and speed restrain the field of view to at most a few EHTs at a time using conventional imaging. To balance the inherent tradeoff among imaging resolution, field of view and speed, an innovative mosaic imaging system was designed, built, and validated to sense contractile force of 3D ECTs seeded on a 96-well plate.

For the programing challenge, we have optimized the conventional cross-correlation algorithms between consecutive time-lapsed images with parallel computing, allowing simultaneous multi-modal readouts for 96 EHTs in real time.

For the engineering challenge, we have prototyped an electrical pacing device that can transmit individually tunable electrical field into each well of the 96-well plate. Work in progress includes long-term and chronic pacing test with EHTs.

Results, Conclusions, and Discussions: Results have shown real-time, simultaneous contractile force and calcium transient monitoring of 96 EHTs for up to 2 hours. Pilot drug testing was conducted using 11 cardiotoxic compounds identified by the FDA CiPA (Comprehensive In Vitro Proarrhythmia Assay) initiative.

Work in progress involves development of parallel electrical pacing and long term drug dosing experiment for up to 3 weeks. Future work will focus on testing different phenotype under clinically relevant dosing conditions.

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