3D Printed Stem-Cell-Laden, Microchanneled Hydrogel Patch for the Enhanced Release of Cell-Secreting Factors and Treatment of Myocardial Infarctions.

Over the past several years, biomaterials loaded with mesenchymal stem cells (MSCs) have increasingly been used to reduce the myocardial fate of postinfarction collagen deposition and scar tissue formation. Despite successful gains, therapeutic efficacy has remained limited because of restricted transport of cell-secreting factors at the site of implantation. We hypothesized that an MSC-laden hydrogel patch with multiple microchannels would retain transplanted cells on target tissue and support transport of cell-secreting factors into tissue. By doing so, the gel patch will improve the therapeutic potential of the cells and minimize the degradation of myocardial tissue postinfarction. To examine this hypothesis, a stereolithographic apparatus (SLA) was used to introduce microchannels of controlled diameters (e.g., 500 and 1000 μm) during in situ cross-linking reaction of poly(ethylene glycol)dimethacrylate solution suspended with cells. Placement of the MSC-laden, microchanneled gel patch on the occluded left coronary artery in a murine model showed significant improvement in the ejection fraction, fractional shortening, and stroke volume, compared with gel patches without MSCs and MSC-laden gel patches without microchannels. In particular, the microchannels significantly reduced the number of cells required to recover cardiac function, while minimizing cardiac remodeling. In sum, the microchanneled gel patch would provide a means to prevent abnormal fibrosis resulting from acute ischemic injury.