Polydopamine/sodium alginate hydrogels with photothermal effects: a drug carrier for NIR-controlled drug release.

As a smart drug carrier, photosensitive hydrogels enable controlled drug release. Here, using polydopamine (PDA) as a photothermal agent additive, a smart PDA/SA hydrogel was constructed by ionic crosslinking of sodium alginate (SA). The PDA/SA hydrogels displayed an ideal capacity for sustained ibuprofen (IBU) release. In vitro release experiments showed that the release of IBU from PDA/SA hydrogels was affected by NIR light. The amount of IBU released from the PDA/SA hydrogel after NIR irradiation was higher than that from the SA hydrogel without NIR irradiation. The PDA/SA hydrogel effectively removed hydroxyl and DPPH radicals, and the scavenging efficiency reached 95.7% and 87.6%. In vitro studies demonstrated that the PDA/SA hydrogels exhibited strong oxidation resistance and excellent cytocompatibility. The hydrogel easily adhered to the surface of skin and the adhesive strength reached 3.8 kPa. Rheological analysis revealed that PDA introduction increased the storage modulus (G') in a frequency-dependent manner, indicative of enhanced physical crosslinking. In summary, the PDA/SA hydrogels possessed increased drug release ability under NIR light, and exhibited excellent cytocompatibility, and prominent antioxidant and tissue adhesion properties. This photosensitive PDA/SA hydrogel is expected to be widely used in the field of drug carriers.