Alginate Fiber in Wound Dressings

The advanced wound care market is experiencing rapid growth due to the increasing prevalence of chronic wounds like diabetic ulcers and post-surgical wounds. Despite being around for decades, alginate dressings are nowadays gaining recognition for their combination of medical utility and sustainable sourcing. They have the ability to create an optimal healing environment by managing wound exudate, promoting tissue regeneration, and minimizing infection risks. As medical professionals seek innovative, eco-friendly solutions, alginate-based products are carving out a significant niche.

Alginate wound dressings are particularly effective for moderate to highly exuding wounds due to their moisture-retentive properties. These dressings turn into a gel when exposed to wound fluid, forming a moist healing environment that accelerates tissue repair and reduces scarring. This unique gel also helps trap bacteria and debris, lowering the risk of infection.

The technical process of transforming seaweed into sodium alginate powder is starting with extraction from brown seaweed continuing through steps of refining and precipitating. Read more about the background here. This sodium alginate is dissolved into a viscous solution, which is then spun into fibers through extrusion technology.

Here’s where the magic happens: during extrusion, the alginate solution is pushed through fine nozzles into a calcium bath, where the fibers undergo ionic crosslinking. The calcium ions replace sodium ions, solidifying the alginate and forming robust, gel-like fibers. These fibers are then processed into sheets or non-woven fabrics, which can be cut into dressings for clinical use.

Each step in the fiber spinning process is crucial. For instance, factors such as the concentration of the alginate solution, the nozzle diameter, and the calcium ion concentration directly influence the final properties of the fiber. These parameters are fine-tuned to produce alginate fibers that are strong enough to maintain structural integrity yet flexible enough to provide comfort when applied to sensitive or delicate wounds.

On the biomaterial side, the sodium alginate powder, which is initially dissolved, needs to be controlled in terms of viscosity and M/G ratio. Those parameters influence the gelation dynamics and process efficiency interacting with the above-mentioned parameters of ion concentration, nozzle diameter and spinning speed. Figure 1 shows the schematic crosslinking of alginate: it happens via ion-complexes of the polymers in their GG-blocks due to the steric orientation.