Injectable Cell-Laden Hydrogels for Tissue Engineering: Recent Advances and Future Opportunities.

Tissue engineering intends to create functionalized tissues/organs for regenerating the injured parts of the body using cells and scaffolds. A scaffold as a supporting substrate affects the cells' fate and behavior, including growth, proliferation, migration, and differentiation. Hydrogel as a biomimetic scaffold plays an important role in cellular behaviors and tissue repair, providing a microenvironment close to the extracellular matrix with adjustable mechanical and chemical features that can provide sufficient nutrients and oxygen. To enhance the hydrogel performance and compatibility with native niche, the cell-laden hydrogel is an attractive choice to mimic the function of the targeted tissue. Injectable hydrogels, due to the injectability, are ideal options for minimally invasive treatment. Cell-laden injectable hydrogels can be utilized for tissue regeneration in a noninvasive way. This article reviews the recent advances and future opportunities of cell-laden injectable hydrogels and their functions in tissue engineering. It is expected that this strategy allows medical scientists to develop a minimally invasive method for tissue regeneration in clinical settings. Impact statement Cell-laden hydrogels have been vastly utilized in biomedical application, especially tissue engineering. It is expected that this upcoming review article will be a motivation for the community. Although this strategy is still in its early stages, this concept is so alluring that it has attracted all scientists in the community and specialists at academic health centers. Certainly, this approach requires more development, and a bunch of crucial challenges have yet to be solved. In this review, we discuss this various aspects of this approach, the questions that must be answered, the expectations associated with it, and rational restrictions to develop injectable cell-laden hydrogels.