Nanocomposite hydrogels with temperature-accelerated antioxidant activity for ocular applications

Area of Science:

• Materials Science
• Biomedical Engineering
• Ophthalmology

Background:

• Oxidative stress significantly contributes to ocular surface disorders.
• Current antioxidant delivery systems face challenges like poor nanoparticle stability, reduced optical clarity, and lack of physiological responsiveness.

Purpose of the Study:

• To develop a thermoresponsive nanocomposite hydrogel for enhanced antioxidant delivery in ocular applications.
• To integrate poly(N-isopropylacrylamide) (pNIPAM) with silver/copper bimetallic nanoparticles (Ag/Cu@Cu) into a unified material platform.

Main Methods:

• Fabrication of a nanocomposite hydrogel by integrating pNIPAM with Ag/Cu@Cu nanoparticles.
• Evaluation of nanoparticle stability, optical transmittance, and redox stability within the hydrogel matrix.
• Temperature-dependent kinetic analysis of antioxidant activity using DPPH assay.

Main Results:

• The pNIPAM matrix effectively stabilized Ag/Cu@Cu nanoparticles, preventing aggregation and maintaining optical transmittance (>70%) at high loadings (up to 25% v/v).
• Encapsulated nanoparticles exhibited improved redox stability and sustained antioxidant activity compared to bare nanoparticles.
• Antioxidant activity showed a temperature-dependent increase, with near-complete DPPH depletion within 120 minutes across tested temperatures (25-35 °C).

Conclusions:

• The developed pNIPAM-Ag/Cu@Cu nanocomposite hydrogels represent a promising platform for optically transparent, stimulus-responsive antioxidant materials.
• This material overcomes limitations of current systems, enabling potential applications in ocular therapeutics, such as contact lenses.
• Quantitatively validated results support the use of these nanocomposite hydrogels for advanced ocular applications.