Injectable biomaterials for stem cell delivery and tissue regeneration

Introduction: Organ dysfunction and failure are major health issues affecting millions of patients, many of whom are desperate for organ transplantation. Tissue regeneration aims at providing alternative solutions through innovative application of cell biology and materials engineering to clinical practice. Biomaterials play a critical role in tissue engineering, which interface with both cell biology and surgical procedures. Injectable stem cell carriers represent a promising platform to harvest the therapeutic effects of cells and to simplify the surgical process. Areas covered: This review is focused on injectable cell carriers which are not only expected to improve therapeutic outcomes, but also to facilitate easy surgical process. Such cell carriers include in situ gelling hydrogel, injectable supramolecular hydrogels, and microcarriers. Expert opinion: The current design of hydrogels and microcarriers can achieve biocompatibility, biodegradability, and provide desirable features to enhance biological response. Overall, more systematic understanding of stem cell behaviors in a synthetic microenvironment, as well as advancement in materials sciences, are needed to design injectable biomaterials that can provide all critical guidance for the full course of tissue regeneration.