Figure 3.

NIR-responsive drug release. (A) Schematic illustration of a tri-bead/azo/DOX microrobot irradiated by NIR light. (B) Thermographic images and (C) DOX release from tri-bead/DOX microrobots and NH₂-Fe₃O₄ beads in PBS buffer at pH 7.4 with and without irradiation. Laser irradiation was performed for 5 min at different times. Asterisks indicate significant differences, *p < 0.05, and the sample number was n = 3. (D) Photothermal heating curves of tri-bead/azo microrobots, NH₂-Fe₃O₄ beads, and PBS solution under 808 nm laser irradiation at a power density of 2 W/cm² at different exposure time.