SMARTHEART®
Human 3D Cardiac microtissue platform

SmartHeart® is a human 3D cardiac microtissue platform based on guided cellular self-assembly, designed for drug testing, cardiac safety assessment and disease modeling.Human iPSC-derived cardiomyocytes and cardiac fibroblasts spontaneously self-assemble into ring-shaped microtissues around deformable hydrogel pillars, without requiring individual tissue manipulation or manual shaping.This controlled architecture provides mechanical resistance during contraction and supports tissue organization and functional maturation, enabling the investigation of integrated electrical, calcium-handling and mechanical responses.SmartHeart® combines these biological features with a standard 96-well format containing nine individually analyzable microtissues per well, low cell requirements and quantitative functional measurements.

SmartHeart® microtissues are generated from human iPSC-derived cardiomyocytes combined with cardiac fibroblasts.The qualified SmartHeart® Contractility Assay uses hiPSC-derived cardiomyocytes and primary human ventricular cardiac fibroblasts at a 3:1 ratio.Alternative cell sources, including disease-specific iPSC-derived cardiomyocytes, may be evaluated depending on the research objectives. Such modifications require appropriate characterization and may require additional assay qualification.

Guided self-assembly allows human cardiac cells to spontaneously organize into three-dimensional tissues within a predefined microenvironment, without requiring individual tissue manipulation or manual shaping.In SmartHeart®, the combination of microwell geometry and deformable hydrogel pillars directs the formation of ring-shaped cardiac microtissues. This approach combines biological self-organization with controlled tissue geometry and mechanical loading.From an experimental perspective, guided self-assembly reduces the need for complex tissue fabrication steps, supports standardized tissue generation and facilitates the production of multiple microtissues with relatively low cell requirements.These characteristics make SmartHeart® particularly suitable for developing scalable human cardiac assays where tissue organization, quantitative functional measurements and experimental reproducibility are essential.

SmartHeart® combines guided cellular self-assembly, controlled tissue architecture, mechanical loading and integrated functional analysis in a scalable human cardiac microphysiological platform.Unlike conventional cardiac spheroids, which generally form without a defined mechanical loading structure, SmartHeart® uses a controlled microenvironment that guides cardiomyocytes and cardiac fibroblasts to spontaneously self-assemble into ring-shaped tissues around deformable hydrogel pillars.This self-assembly process generates organized 3D cardiac microtissues without requiring individual tissue manipulation or manual shaping. The resulting architecture provides mechanical resistance during contraction and supports tissue organization and functional maturation, creating conditions in which electrical excitation, intracellular calcium handling and mechanical contraction can function as interconnected processes.Rather than assessing isolated cellular endpoints, SmartHeart® enables the investigation of integrated electromechanical responses and their modulation by pharmacological compounds.Importantly, its self-assembly approach also supports scalability and experimental standardization: nine microtissues are generated per well in a standard 96-well plate, with approximately 7,200 cells per microtissue, compatibility with in situ optical measurements and potential for automated workflows.While self-assembly is also used in other engineered heart tissue systems, SmartHeart® is differentiated by the combination of guided tissue formation, defined mechanical loading, integrated functional assessment and low-cell-input multiwell architecture.

Each SmartHeart® well contains nine individual microtissue-forming structures, allowing up to 864 cardiac microtissues to be generated in a 96-well plate.The qualified contractility workflow uses approximately 65,000 cells per well, corresponding to approximately 7,200 cells per microtissue.Each microtissue can be analyzed individually, enabling assessment of within-well variability and tissue-level functional responses.These measurements provide multiple observations under the same experimental condition but do not represent nine independent biological experiments.

SmartHeart® supports three complementary categories of functional measurements:Contractility: Contraction strain, derived contractile stress, contraction and relaxation speeds, contraction and relaxation timing, beating frequency and rhythm regularity.Electrophysiology: Optical action potential characteristics, including action potential duration and repolarization kinetics.Calcium handling: Calcium transient amplitude, rise and decay kinetics, and transient duration.These complementary measurements help investigate excitation–contraction coupling and drug-induced changes in human cardiac tissue function.The availability, experimental conditions and qualification status of each measurement depend on the selected assay workflow.

SmartHeart® uses brightfield video microscopy to record the spontaneous contractions of ring-shaped cardiac microtissues.SmartX™ Analysis tracks changes in tissue geometry throughout the contraction-relaxation cycle and extracts quantitative mechanical parameters, including contraction strain, beating frequency and contraction/relaxation kinetics.Contractile stress can also be estimated using the mechanical properties of the hydrogel pillar.This label-free contractility workflow allows repeated functional measurements without requiring fluorescent reporters or dyes.

SmartHeart® can support the development of human 3D cardiac disease models by combining disease-relevant cardiac cells with quantitative functional measurements.Potential applications include investigating altered contractility, relaxation abnormalities, calcium-handling defects and electrophysiological dysfunction associated with cardiovascular diseases.Disease-specific studies, including research on dilated or hypertrophic cardiomyopathies, require suitable cell sources, characterization of the disease phenotype and fit-for-purpose experimental validation.SmartHeart® provides the underlying platform; the suitability and performance of individual disease models must be established for each application.

Yes. SmartHeart® is available as a 96-well plate platform for laboratories wishing to generate and study human 3D cardiac microtissues in-house.The glass-bottom format supports optical imaging, while compatible SmartX™ Analysis workflows enable quantitative contractility measurements.4Dcell can provide technical guidance regarding cell selection, tissue generation, imaging requirements and data analysis.Alternatively, pharmaceutical and biotechnology companies can access SmartHeart® through 4Dcell's cardiac testing services.

SmartHeart® can be incorporated into experimental designs involving electrical stimulation or longer-duration culture and exposure protocols.Electrical pacing can help investigate rate-dependent cardiac responses, while longer-term studies may support assessment of delayed or sustained pharmacological effects.These applications are distinct from the qualified acute, spontaneously beating contractility workflow. Their availability, experimental configuration and performance requirements should be discussed with 4Dcell before study initiation.