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

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 cross-linker 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.