Functionalized alginate for biomedical application

Alginates are used to cover wounds or deliver drugs. They are natural polymers that occur in seaweed, with a whole list of favorable properties, including biocompatibility, low toxicity, abundant availability, and ease of gelation. In her research, Arlina Putri developed a gel with alginate derivatives with low molecular weight.

Putri investigated chemical functionalization like oxidation as a potential way to generate alginate derivatives with a low molecular weight. She looked at the required ratio of oxidation agent and sodium alginate as substrate. The oxidation reaction led to pyran ring opening and the formation of di-aldehyde, the so-called alginate dialdehyde (ADA) as much as 0.82 and 0.12 mol of aldehyde per mol repeating unit of alginate. The advantages of ADA are lower molecular weight and newly formed active aldehyde functional groups, which depend on the degree of oxidation. 

Putri: 'The new available functional groups open a new opportunity to conduct reductive amination reactions to graft a new targeting branch on the alginate structure. This reaction could be conducted using sodium cyanoborohydride, sodium borohydride, and picoline borane complex.'

The newly formed polymer product can be formed as hydrogel either using Schiff base reaction with gelatin to form crosslinking or with ionic crosslinker like calcium chloride. The resulting hydrogel is shear-thinning and self-healing, making it suitable for biomedical applications. The grafting study of ADA with plant lectin Wheat Germ Agglutinin (WGA), generated a microgel product suitable for curcumin encapsulation. The cytotoxicity study demonstrated that the microgels at low concentrations were suitable for the drug delivery matrix.

Dissertation: https://hdl.handle.net/11370/b3a5fcd2-08ca-4a88-a089-60d96cbc0210