Controlled drug release from PNIPAM-incroporated melanin nanovesicles by photo-stimulation

To minimize side effects and increase drug efficacy, a novel strategies are needed to facilitate rapid drug release at the lesion site. In this study, a nanovesicle composed of phospholipids including melanin, poly(N-isopropylacrylamide-co-acrylamide) (PNIPAM) and 5-fluorouracil (5-FU) is suggested for thermoresponsive drug release by near-infrared (NIR) laser irradiation. The novel aspect of the nanovesicles is the use of melanin, which has excellent biocompatibility. The nanovesicle was 180.4 +/- 1.6 nm in size and stable for 1 week. After exposure to NIR laser, the temperature of the nanovesicle solution was increased above 51 degrees C by the photothermal effect of melanin. The rate of 5-FU release from the nanovesicle was increased by about 14% for 12 h, following exposure to the laser irradiation compared with no such exposure. The drug release rate was increased depending on the amount of PNIPAM. Consequently, the nanovesicle has a potential application in NIR laser-responsive drug release.