Now that we have finished covering polymers, ceramics, and metals, we have started to focus on composites. Composites are made up of multiple of materials. In the case of the device I am reviewing, the material is a hydrogel that is composed of both bioglass and agarose-alginate(AA).
The material in the article is a hydrogel and is used as an innovative dressing for wounds. As I’ve discussed in previous blog posts, chronic wounds are a major rising issue especially with the influx of people with diabetes. The body’s inability to repair itself leads to chronic wounds, therefore new materials try to aid the wound healing process This particular material attempts to do this by addressing the humidity at the wound site and also by increasing the ability of angiogenesis.
The material makes use of bioglass’ ability to aid wound healing by promoting angiogenesis, and AA’s ability to create a humid environment. As we learned in lecture, composite materials will not merge together, but instead the composite will have a mixture of properties of the used materials, which in this case would be ceramics and polymers. For this reason, bioglass and AA should both have the same effect that they normally have within the body. However, these materials will work together because the moist environment created by AA allows for the bioglass to release bioactive molecules that will improve the process of creating new blood vessels. If blood is able to effectively flow to the wound site, then there is a higher probability of the wound healing.
The in vivo experiment tested the material at different ratios of agarose and alginate on a rabbit ear’s wound, and it was seen that the models with bioglass and AA performed better (figure shown below). The conclusion was that since more endothelial cells and fibroblasts migrated to the area and due to the increased humidity, then the body was able to heal at a more rapid pace.
When deciding what materials to use, the researches mentioned that although bioglass has useful properties, it is normally used in a powder form which can be difficult to use for a wound site. They were able to fix this issue by combining it with AA, which can make the material temperature dependent for gelation, and thus a material that is both injectable and can solidify at a wound site as need was created. Ultimately, different materials have their own individual advantages and disadvantages; however, composite materials are able to combine the best aspects of multiple materials to create new biomaterials with the most ideal characteristics.
Zeng, Q., Han, Y., Li, H., & Chang, J. (2015). Design of a thermosensitive bioglass/agarose–alginate composite hydrogel for chronic wound healing. Journal of Materials Chemistry B, 3(45), 8856-8864.