Supporting data for All-aqueous Microfluidics Fabrication of Novel Fibrous Scaffolds for Wound Healing

Hydrogels have undergone significant advancements since the development of the original polymeric hydrogel network 80 years ago. These versatile materials have found applications in various fields, including drug release, tissue regeneration, and medical dressing. However, while natural hydrogels possess complex structures and functions at different scales, synthetic hydrogels remain limited in their simplicity. The challenge lies in creating hydrogels with intricate structures and functions tailored to specific biomedical applications and organs. As drug delivery vehicles, hydrogels exhibit excellent biocompatibility and are ideal for sustained drug release. Current research focuses on achieving on-demand release of multiple drugs from a single system with precise control. Although the release of multiple drugs has been demonstrated, fine-tuning the release rates of different molecules remains a challenge. The ability to control drug release is particularly crucial in tissue repair and regeneration, which involves sequential signaling of several growth factors. Furthermore, three-dimensional (3D) synthetic biomaterials, acting as structural and bioactive scaffolds, play a vital role in fields ranging from cellular biophysics to regenerative medicine. By developing synthetic 3D microporous biomaterials resembling extracellular matrices, cell and tissue development can be studied in the presence of biochemical stimulants. This development area is crucial for understanding the intricacies of cell behavior and tissue formation. Hydrogel-based artificial scaffolds are also instrumental in transitioning from two-dimensional cell culture to 3D models, offering a more realistic representation of in vivo disease treatment and pharmacological responses.

In our current study, we employ all-aqueous microfluidics to engineer microfibers, which serve as the building blocks for reaction-free and interaction-free biocompatible hydrogels. These microfiber-based hydrogels find applications as medical dressings, drug delivery vehicles, and 3D artificial scaffolds. In vitro, we investigate the relationship between porosity, swelling behavior, mechanical properties, and fiber lengths of these hydrogels. Furthermore, we introduce an innovative approach to controlling drug release profiles by simply adjusting the microfiber lengths. Longer microfibers result in sustained drug release over an extended period. This tunable drug release allows for the creation of multi-layered hydrogels with varying drug release rates. Additionally, our microfiber-based hydrogels scaffold demonstrates excellent potential for 3D cell culture, showcasing favorable biocompatibility in preliminary tests. Further research will explore its performance in more complex models and tissue engineering applications. In vivo, we have demonstrated the potential of microfiber-based hydrogels in wound healing through excision skin and diabetic wound models. As a multi-drug delivery system, these hydrogels accelerate wound healing when used as medical dressings. The results indicate that microfiber-based hydrogels promote faster wound healing and regeneration of healthy tissue compared to commercial gels. Moreover, by achieving distinct drug release rates in a two-layer microfiber-based hydrogels model, we enhance wound healing efficiency in both the excision wound and the diabetic wound. The combination of injectability and customizable properties in the microfiber-based hydrogels offers a promising approach for therapeutic delivery, medical dressings, and 3D tissue scaffolds in various biomedical applications.