This study manufactured antioxidant contact lenses using tannic acid, a
natural antioxidant, and seaweed polysaccharides (carrageenan and alginate),
evaluated the properties, and improved its antioxidant duration.
The antioxidant contact lenses were prepared to include monomers, such as
2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA), and 0.1% ∼
0.5% of tannic acid.
The contact lenses containing tannic acid were dual-networked with alginate
and carrageenan using the Interpenetrating Polymer Network (IPN) method.
Finally, the contact lenses dual-networked with seaweed polysaccharides were
crosslinked with calcium ions. The performance of these lenses was evaluated
by examining the antioxidant properties by the radical scavenging rate and
physical properties such as light transmittance, water content, oxygen
permeability, and wettability, and biochemical properties such as protein
adsorption and antibacterial properties.
The contact lenses containing tannic acid had antioxidant properties, and the
higher the tannic acid content, the greater the antioxidant effect.
In terms of the properties of the contact lenses dual-networked with
carrageenan and alginate, the antioxidant duration increased compared to
non-networked lenses. In particular, performing IPN with seaweedpolysaccharides on lenses containing 0.1% tannic acid resulted in a low radical
scavenging rate but a very long antioxidant duration.
In terms of the physical properties of the contact lenses according to tannic
acid content, the water content and oxygen permeability improved as the tannic
acid concentration increased, but the wettability decreased. In addition, as the
concentration of tannic acid in the contact lenses increased, protein adsorption
decreased, and the antibacterial effect increased. Among seaweed
polysaccharides, alginate had more influence on improving the biochemical
properties than carrageenan.
The contact lenses that were additionally crosslinked with calcium ions had
increased antioxidant properties compared to before crosslinking. There was
almost no change in water content, oxygen permeability, and wettability
according to increasing the concentration of tannic acid, and alginate had a
better effect on the physical properties of the lenses than carrageenan. The
protein adsorption of the contact lenses crosslinked with calcium tended to
decrease significantly as the concentration of tannic acid increased.
Crosslinking seaweed polysaccharides and metal ions with contact lenses
containing tannic acid improved the antioxidant and physicochemical properties
of the lenses and extend the antioxidant duration