Design of a near-infrared-triggered photo/thermal dual-responsive composite carrier with excellent biocompatibility for controllable drug release

A near-infrared (NIR)-triggered photo/thermal dual-responsive composite carrier (UCNPs-NG-PDA) was designed and fabricated by the incorporation of upconversion nanoparticles (UCNPs), coumarin-based photo/thermal-responsive nanogel (NG) with uniform particle size (193 nm) and polydopamine (PDA) particles. UCNPs-NG-PDA has good photothermal conversion capability because of the introduction of PDA. The light and heat dual-responsiveness of coumarin-based nanogels markedly enhances the drug release of UCNPs-NG-PDA. Under NIR irradiation for only 20 min, the final cumulative release reaches 79.4% and is much higher than that (58.8%) under UV irradiation. More remarkably, the UCNPs-NG-PDA exhibits an excellent biocompatibility and has fascinating application prospects in drug delivery fields.