Direct hydrogel encapsulation of pluripotent stem cells enables ontomimetic differentiation and growth of engineered human heart tissues

Abstract

Human engineered heart tissues have potential to revolutionize cardiac development research, drug-testing, and treatment of heart disease; however, implementation is limited by the need to use pre-differentiated cardiomyocytes (CMs). Here we show that by providing a 3D poly(ethylene glycol)-fibrinogen hydrogel microenvironment, we can directly differentiate human pluripotent stem cells (hPSCs) into contracting heart tissues. Our straight-forward, ontomimetic approach, imitating the process of development, requires only a single cell-handling step, provides reproducible results for a range of tested geometries and size scales, and overcomes inherent limitations in cell maintenance and maturation, while achieving high yields of CMs with developmentally appropriate temporal changes in gene expression. Here we demonstrate that hPSCs encapsulated within this biomimetic 3D hydrogel microenvironment develop into functional cardiac tissues composed of self-aligned CMs with evidence of ultrastructural maturation, mimicking heart development, and enabling investigation of disease mechanisms and screening of compounds on developing human heart tissue.

Striated muscle function, regeneration, and repair

“…In particular, numerous groups have engineered 3D cardiac tissues from hESCs and hiPSCs [163, 282–285] that generated specific forces ranging from 0.08 mN/mm 2 [286] to 11.8 mN/mm 2 [287] and conduction velocities ranging from 4.9 cm/s [288] to 25.1 cm/s [287, 289]. Thus, further progress in the field will be necessary to bring the state of human cardiac tissue engineering closer to replicating the robust phenotype of the adult human myocardium (specific forces of 25–44 mN/mm 2 [290, 291], average conduction velocity of ~50 cm/s [292]).…”

“…For example, 3–4 month 2D culture of hPSC-CMs has produced structurally and electrophysiologically more mature cardiomyocytes [297], while 1-year 2D-cultured hPSC-CMs demonstrated appearance of M-bands (in <10% of CMs), a hallmark of advanced sarcomeric maturation [298]. Recently, a 4-month long culture within 3D PEG (poly(ethylene glycol))-fibrinogen hydrogels yielded the formation of T-tubules in hPSC-CMs [282]; still the CM volume in all these studies remained significantly smaller than that of the adult CMs.…”

PEG‐fibrinogen hydrogels for three‐dimensional breast cancer cell culture

“…When fibrinogen is covalently conjugated with poly(ethylene glycol) diacrylate (PEGDA), it forms PEG‐fibrinogen (PF) via Michael‐type addition reaction between thiol groups on the cysteine sites in the fibrinogen molecule and the PEGDA polymeric chains . PF can be photocrosslinked to form hydrogels in the presence of Eosin Y using visible light under physiological temperature and pH . This capability renders it suitable for encapsulation and culture of a wide variety of cell types including smooth muscle cells (SMCs), induced pluripotent stem cells (iPSCs), chondrocytes, and others .…”

Biomaterials control of pluripotent stem cell fate for regenerative therapy

“…Moreover, the human ESCs differentiated into cardiomyocytes with the introduction of ascorbic acid and demonstrated the beating behavior at 19 days. Similarly, the PEG-fibrinogen based hydrogels were also shown to be successful to 3D culture iPSCs and then differentiate them into cardiomyocytes [257]. The hydrogels were able to culture both cellular clusters and single cells to create reproducible cardiac tissue.…”