Biomedical Applications of Alginate Hydrogels

Alginate hydrogels have many useful biomedical applications due to their properties because of this they are used in pharmaceuticals for drug delivery and for protein delivery, alginate hydrogels are also used in wound dressing and are preferred over the traditional wound dressing such as gauze⁷.

Pharmaceutical Applications

Drug Delivery

Alginate hydrogels have been investigated for their use in delivering low molecular weight drugs^7-8, the alginate gels are normally nanoporus (pore size ~5nm). Because of this there is a rapid diffusion of the small drug molecules through the gel. An example of this would be the release of a chemical know as flurbiprofen, this drug was released from an ionically cross-linked alginate gel that was also partially oxidized. The release of flurbiprofen was very quick as the release of the drug was completed in around 1.5 hours⁷.

Protein Delivery

Alginate hydrogels have been investigated in protein delivery as the proteins can be incorporated into the alginate gel under mild conditions, because of these mild conditions  there is little denaturation of the protein⁷. When the proteins have been incorporated into the gel they are protected from degradation until they are released, therefore the protein remains intact whilst it is in the gel. The release rate is fairly rapid due to the hydrophilicity and the porosity of the gels, however there are methods in manipulating the release of the proteins from the gels, one such method is using partially oxidised alginate gels. These oxidised gels alter the degradation rate of the gel, this makes the protein release dependent on the degradation reaction of the gels.⁷

Wound Dressing

Treating wounds is one of the most common roles in medicine, it is done by placing a dressing over the wound by doing this the wound is kept dry and it prevents the wound from becoming infected due to entry of a pathogen^4,7. Because of the importance of wound dressings alginate based wound dressings have been looked into as replacements for the traditional gauze dressings as these traditional dressings mainly provide a barrier for the wound to prevent the entry of pathogens. Alginate wound dressings have many advantageous features that make them more suitable than the traditional gauze dressings. These alginate gels are formed by ionically cross-linked alginate solution with calcium ions, this is then followed by processing in order to form fibrous non-woven dressing and freeze-dried porous sheets^4,7. These freeze-dried porous sheets are very useful in wound dressing as they absorb the wound fluid which causes it to re-gel where it can now supply water to the dry wound, this maintains a moist environment for the wound to heal in and it also prevents bacterial infection.⁷