Microfluidic fabrication of calcium alginate helical microfibers for highly stretchable wound dressing

Due to suitable biocompatibility and biodegradability, natural polymers have a wide range of applications in the biomedical field, but the defects of mechanical properties limit their performance in some practical scenarios. Here, the microfluidic method was used to spin alginate into helical fibers, and then the gaps of packed microfibers were filled with polyacrylamide (PAM) to obtain a calcium alginate/PAM composite polymer membrane. Compared with pure calcium alginate, this composite film greatly improved the flexibility and stretchability, and could be stretched up to 14 times of its original length, and not deform significantly under 300% strain for 8 cycles. It also had good transparency and skin adhesion, further guaranteeing the application potential in the field of wound dressings. The loading and release experiments showed that the calcium alginate fibers maintained a dense morphology, and could achieve higher loading efficiency and more controllable release than pure PAM. Above all, this film has great application potential in joint wound dressings, especially when loading with antibacterial substances or healing-promoting drugs is needed. In addition, our research of achieving substantial optimization of elasticity and stretchability through the introduction of helical shape also has certain reference significance for other natural polymers limited by mechanical properties.