Injectable hydrogels revolutionize cell and drug delivery for tissue repair

This emerging technology, highlighted in a special research collection published by Frontiers in Bioengineering and Biotechnology​, focuses on the development of hydrogels as carriers for cells and therapeutics, which could significantly enhance the efficacy of in-situ tissue repair.

Injectable hydrogels, which are crosslinked networks of hydrophilic polymers, mimic the physical properties of soft tissues. Their ability to incorporate cells and therapeutic molecules makes them ideal for promoting cellular growth in-vitro and tissue regeneration in-vivo. Unlike traditional prefabricated scaffolds that require invasive surgical procedures for transplantation, injectable hydrogels can be delivered with minimal invasiveness, reducing patient recovery times and healthcare costs.

However, the editorial notes that the road to clinical application is not without its challenges. Issues such as mechanical integrity, the viability of encapsulated cells, biocompatibility, and scalable manufacturing processes must be addressed before these materials can be widely adopted in medical practice.

The research featured in this collection showcases several cutting-edge studies exploring the potential of hydrogels in various therapeutic contexts. For example, a study by Cohen et al. developed polyethylene glycol-fibrinogen hydrogel microspheres to encapsulate immune cells, specifically alveolar macrophages and epithelial cells, for respiratory tract repair. The encapsulated cells maintained high viability and function when exposed to bacterial endotoxins, demonstrating the feasibility of polymer-encapsulated cell delivery for tissue repair.

Another exciting development comes from Sun et al., who created an injectable, adhesive, and self-healing composite hydrogel system loaded with oxybutynin hydrochloride for treating overactive bladder (OAB). Their research demonstrated that the hydrogel could modulate intracellular calcium concentrations, offering a significant improvement over conventional oxybutynin therapies. This breakthrough could lead to more effective management of OAB and other related conditions.

The collection also highlights innovations in cancer therapy. Zhou et al. developed chitosan-based hydrogels modified with lactobionic acid (LA) and cinnamaldehyde (CA) for targeted drug delivery. These hydrogels were loaded with the anticancer drug doxorubicin (DOX) and showed enhanced stability, target specificity, and anti-tumor efficacy compared to free DOX solutions. This approach could potentially overcome one of the major challenges in cancer treatment: the efficient and targeted delivery of therapeutic agents.

Further contributions in the collection include a study by Liu et al., which explored alternative crosslinking agents for heart valve tissue engineering. The researchers aimed to reduce the long-term toxic effects associated with traditional glutaraldehyde crosslinking. Their hybrid crosslinking strategy not only improved the biocompatibility and durability of the materials but also minimized calcification and inflammation in preclinical models, marking a significant step forward in the development of safer biomaterials.

Additionally, a comprehensive review by Xu et al. discusses the latest advances in the design and fabrication of hydrogels, particularly focusing on challenges related to clinical translation. The review emphasizes the importance of developing scalable, sterile, and user-friendly hydrogel scaffolds for successful clinical application.

Collectively, these studies underscore the transformative potential of injectable hydrogels in tissue engineering and regenerative medicine. As research progresses, addressing the current challenges related to mechanical properties, cell viability, and bioactivity will be crucial for the eventual translation of these promising materials into clinical therapies. The work featured in this editorial not only highlights the exciting progress being made but also sets the stage for future innovations that could revolutionize the field of tissue engineering.