Engineering stem cell therapeutics for cardiac repair

Cardiovascular disease is the leading cause of death in the world. Stem cell-based therapies have been widely investigated for cardiac regeneration in patients with heart failure or myocardial infarction (MI) and surged ahead on multiple fronts over the past two decades. To enhance cellular therapy for cardiac regeneration, numerous engineering techniques have been explored to engineer cells, develop novel scaffolds, make constructs, and deliver cells or their derivatives. This review summarizes the state-of-art stem cell-based therapeutics for cardiac regeneration and discusses the emerged bioengineering approaches toward the enhancement of thera-peutic efficacy of stem cell therapies in cardiac repair. We cover the topics in stem cell source and engineering, followed by stem cell-based therapies such as cell aggregates and cell sheets, and biomaterial-mediated stem cell therapies such as stem cell delivery with injectable hydrogel, three-dimensional scaffolds, and microneedle patches. Finally, we discuss future directions and challenges of engineering stem cell therapies for clinical translation.