Creation of a Contractile Biomaterial From a Decellularized Spinach Leaf Without ECM Protein Coating: An in vitro study.

Myocardial infarction (MI) results in the death of cardiac tissue, decreases regional contraction, and can lead to heart failure. Tissue engineered cardiac patches containing human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) can restore contractile function. However, cells within thick patches require vasculature for blood flow. Recently, we demonstrated fibronectin coated decellularized leaves provide a suitable scaffold for hiPS-CMs. Yet, the necessity of this additional coating step is unclear. Therefore, we compared hiPS-CM behavior on decellularized leaves coated with collagen IV or fibronectin extracellular matrix (ECM) proteins to non-coated leaves for up to 21 days. Successful coating was verified by immunofluorescence. Similar numbers of hiPS-CMs adhered to coated and non-coated decellularized leaves for 21 days. At day 14, collagen IV coated leaves contracted more than non-coated leaves (3.25+/-0.39% vs. 1.54+/-0.60%; p<0.05). However, no differences in contraction were found between coated leaves, coated tissue culture plastic (TCP), non-coated leaves, or non-coated TCP at other time points. No significant differences were observed in hiPS-CM spreading or sarcomere lengths on leaves with or without coating. This study demonstrates that cardiac scaffolds can be created from decellularized leaves without ECM coatings. Non-coated decellularized leaf surfaces facilitate robust cell attachment for an engineered tissue patch.