Folic acid mediated solid lipid nanocarriers loaded with docetaxel and oxidized single-walled carbon nanotubes

Single-walled carbon nanotubes (SWNT) possess high-near-infrared absorption coefficient, large surface area, and have great potential in drug delivery. In this study, we obtained ultrashort oxidized SWNT (OSWNT) using mixed acid oxidation method. Then, docetaxel (DTX) and folic acid (FA) are conjugated with OSWNT via π–π accumulation and amide linkage, respectively. A targeting and photothermal sensitive drug delivery system FA–DTX–OSWNT–SLN was prepared following a microemulsion technique. The size and zeta potential of FA–DTX–OSWNT–SLN were 182.8 ± 2.8 nm and −34.59 ± 1.50 mV, respectively. TEM images indicated that FA–DTX–OSWNT–SLN was spherical and much darker than general solid lipid nanoparticles (SLN). Furthermore, OSWNT may wind round, insert into or be encapsulated into the nanocarriers. Compared with free DTX, FA–DTX–OSWNT–SLN could efficiently cross cell membranes and afford higher antitumor efficacy in MCF-7 cells in vitro. Meanwhile, the combination of near-infrared laser (NIR) irradiation at 808 nm significantly enhanced cell inhibition. In conclusion, FA–DTX–OSWNT–SLN drug delivery system in combination with 808 nm NIR laser irradiation may be promising for targeting and photothermal cancer therapy with multiple mechanisms in future.