A Layer-by-Layer Single-Cell Coating Technique To Produce Injectable Beating Mini Heart Tissues via Microfluidics

Abstract

Human induced pluripotent stem cells (hiPSCs) are used as an alternative for human embryonic stem cells. Cardiomyocytes derived from hiPSCs are employed in cardiac tissue regeneration constructs due to the heart's low regeneration capacity after infarction. A coculture of hiPSC-CM and primary dermal fibroblasts is encapsulated in injectable poly(ethylene glycol)-based microgels via microfluidics to enhance the efficiency of regenerative cell transplantations. The microgels are prepared via Michael-type addition of multi-arm PEG-based molecules with an enzymatically degradable peptide as a crosslinker and modified with a cell-adhesive peptide. Cell−cell interactions and, consequently, cell viability are improved by a thin extracellular matrix (ECM) coating formed on the cell surfaces via layer-by-layer (LbL) deposition. The beating strength of encapsulated cardiomyocytes (∼60 BPM) increases by 2-fold compared to noncoated cells. The combination of microfluidics with the LbL technique offers a new technology to fabricate functional cardiac mini tissues for cell transplantation therapies.

Mechanical activities of self-beating cardiomyocyte aggregates under mechanical compression

“…Another important aspect is that the dynamic beating energy that a single CS produces in a single contraction strongly depends on the static mechanical compression applied immediately before the contraction. Immature CMs such as hiPSC-CMs beat spontaneously alone 18,19,46,47 ; aggregates such as CSs consisting of immature CMs, sometimes termed "mini heart tissue" 48 , also beat spontaneously as a whole 18,21,22 , utilizing the mechanical-electrical feedback of CMs [37][38][39] and the electrical communication between CMs in direct contact [18][19][20][21][22][23][24][25] . However, in reality, the mechanical pulsations of CSs were extremely weak unless they were compressed mechanically (Fig.…”

Controlling Structure with Injectable Biomaterials to Better Mimic Tissue Heterogeneity and Anisotropy

“…Reproduced with permission. [8,103,145] Copyright 2017, 2019, American Chemical Society. Further permissions related to excerpts from these materials should be directed to the ACS.…”

“…The flow rates of the two phases, their respective capillary numbers, along with the chip geometry, determine whether the system will go into a dripping or jetting regimes, which are then utilized for microgel production, covering a wide range of achievable sizes and aspect ratios. [160,161] Multiple works have demonstrated the ability to encapsulate cells into these microgels on chip (Figure 5E), [146,162,163] resulting in cell spreading and function, such as beating induced-pluripotent stem cell-derived cardiomyocytes in coculture with fibroblasts, [145] long-term cell culture of MSCs for up to 28 days and differentiation of encapsulated MSCs. [164] In another work, MSCs were first encapsulated in alginate microgels on chip, followed by a prolonged culture in vitro to form cell clusters within the microgels.…”

Fabrication and Biomedical Applications of Heart-on-a-chip

“…The traditional materials for microfluidic chips include glass, silicon, polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), and papers[ 10 ]. Silicon and glass are compatible to the standard micro- or nano-fabrication methods (photolithography, etching, etc.).…”