Thermally reversible and light-sensitive agarose hydrogels for controlled drug release

Significant work has been conducted in the development of stimuli-responsive hydrogels for triggered drug delivery, most systems still lack the ability to enable externally controlled, on-demand drug delivery over several independent cycles. This study investigates the development and performance of an agarose-based hydrogel composite integrated with poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles for enhanced drug delivery applications. We synthesized a stable hydrogel from low-melt and low-electroendosmosis agarose and incorporated PEDOT nanoparticles to enable photothermal modulation using near-infrared (NIR) light. PEDOT nanoparticles were initially synthesized via emulsion polymerization and characterized for size distribution, zeta potential, UV-Vis absorbance, and photothermal conversion ability to confirm their successful formation. The agarose-PEDOT composite hydrogel was then prepared and evaluated comprehensively, including for photothermal performance and drug release capacity. Photothermal studies demonstrated the hydrogel's ability to absorb NIR light at 808 nm, indicating its potential for controlled, laser-triggered drug release. Drug release experiments were conducted using bovine serum albumin-fluorescein isothiocyanate (BSA-FITC) and doxorubicin (DOX) as model drugs. These studies were performed at room temperature, 37°C, and under 808-nm laser irradiation to assess the hydrogel's responsiveness to thermal and photothermal stimuli. The results showed that the agarose-PEDOT composite hydrogel exhibited excellent stability in a liquid medium, effectively retaining PEDOT nanoparticles. Additionally, the hydrogel demonstrated pulsatile release behavior for both BSA-FITC and DOX under NIR laser irradiation, providing a controllable and sustained release profile. In conclusion, this composite hydrogel offers promising potential for targeted and controlled drug delivery, particularly in applications requiring light-responsive release mechanisms.