Injectable Hydrogels Based on Hyperbranched Polymers for Biomedical Applications.

Injectable hydrogels (IHs) have garnered significant attention in biomedical applications due to their minimally invasive nature, adaptability, and high degree of customization. However, traditional design methods of IHs have limitations in addressing complex clinical needs, such as precise regulation of the gelation time and mechanical strength within a wide window. Hyperbranched polymers (HBPs), due to their unique highly branched structures and abundant functional sites, can be easily prepared and functionalized to enable decoupled modulation of mechanical properties of IHs and address the clinical challenges of IHs. Our research group developed a library of HBPs via a dynamically controllable polymerization method and built a series of adjustable, controllable, and responsive IHs based on the resulting HBPs. The prepared IHs fed by HBPs demonstrate an adjustable gelation process, a wide-range tuning of mechanical properties, and responsiveness on demand, which show the capabilities in the various biomedical applications. In this review, we summarize the role of HBPs in the gelation process, mechanical properties, self-healing ability, and responsiveness of IHs. However, achieving IHs through HBPs and extending them to a broad range of biomedical applications are still in its infancy. This review provides an overview of IHs fabricated by a variety of multifunctional HBPs, and their biomedical applications in diverse fields are also presented. Meanwhile, we point out the future development of IHs based on HBPs and their potential challenges.