Functional arrays of human pluripotent stem cell-derived cardiac microtissues

Nimalan Thavandiran,Mark L Sandberg,Ian Fernandes,Andrew Prowse,Alec Witty,Milica Radišić ,Mark Gagliardi,Tal Vana ,Patrick H Blit ,George Graham,Michele Mcelvain ,Hon Le,Erik Chau,Gordon Keller,Mohsen Afshar Bakooshli,Christopher M Hale ,Joel Östblom ,Bo Sun,Penney M Gilbert,Philip Tagari,A Gregson Norman ,Samuel Mcewen,Han Xu,Peter W Zandstra

doi:10.1038/s41598-020-62955-3

Abstract

To accelerate the cardiac drug discovery pipeline, we set out to develop a platform that would be capable of quantifying tissue-level functions such as contractile force and be amenable to standard multiwell-plate manipulations. We report a 96-well-based array of 3D human pluripotent stem cell (hPSC)-derived cardiac microtissues - termed Cardiac MicroRings (CaMiRi) - in custom 3D-print-molded multiwell plates capable of contractile force measurement. Within each well, two elastomeric microcantilevers are situated above a circumferential ramp. The wells are seeded with cell-laden collagen, which, in response to the gradual slope of the circumferential ramp, self-organizes around tip-gated microcantilevers to form contracting CaMiRi. The contractile force exerted by the CaMiRi is measured and calculated using the deflection of the cantilevers. Platform responses were robust and comparable across wells, and we used it to determine an optimal tissue formulation. We validated the contractile force response of CaMiRi using selected cardiotropic compounds with known effects. Additionally, we developed automated protocols for CaMiRi seeding, image acquisition, and analysis to enable the measurement of contractile force with increased throughput. The unique tissue fabrication properties of the platform, and the consequent effects on tissue function, were demonstrated upon adding hPSC-derived epicardial cells to the system. This platform represents an open-source contractile force screening system useful for drug screening and tissue engineering applications.

Highlights

To accelerate the cardiac drug discovery pipeline, we set out to develop a platform that would be capable of quantifying tissue-level functions such as contractile force and be amenable to standard multiwell-plate manipulations
We designed a platform that would allow us to culture and measure the contractile forces exerted by cardiac microtissues
The platform consists of wells containing dual polydimethylsiloxane (PDMS) cantilevers around which Cardiac MicroRings (CaMiRi) form due to the compaction of a collagen 1-based matrix by the cardiomyocytes and cardiac fibroblasts contained within (Fig. 1A)

Summary

Introduction

To accelerate the cardiac drug discovery pipeline, we set out to develop a platform that would be capable of quantifying tissue-level functions such as contractile force and be amenable to standard multiwell-plate manipulations. The wells are seeded with cell-laden collagen, which, in response to the gradual slope of the circumferential ramp, self-organizes around tip-gated microcantilevers to form contracting CaMiRi. The contractile force exerted by the CaMiRi is measured and calculated using the deflection of the cantilevers. The displacement of this deflection can be imaged via a digital camera in each well and used to calculate a total magnitude contractile force, using both the structural and material properties of the elastomer microcantilevers We optimized this platform by conducting a Central Composite Design (CCD) experiment to test the effects of several input variables on the contractile force exerted by the CaMiRi. We validated our platform with a cardiotoxicity study using compounds with known effects on cardiomyocyte contractile force response and automated key bottlenecks in the experimental process to enable high throughput measurement of contractile force. This platform provides a widely accessible solution for functional screening and validation of cardiac-associated drugs

Methods

Results

Conclusion