pH/near infrared dual-triggered drug delivery system based black phosphorus nanosheets for targeted cancer chemo-photothermal therapy.

Recently, chemo-photothermal has been developed as a promising strategy for cancer therapy. However, as a novel photothermal material, black phosphorus nanosheet (BP NSs) has the disadvantages of complicated preparation procedures, high purchase price and poor drug selectivity, which limits its application. Herein, BP NSs have been successfully prepared by self-made ultrasonic method, which was a simple and rapid laboratory preparation. Then, BP NSs based co-delivery system, which coated with mitoxantrone hydrochloride (MTX) and hyaluronic acid (HA) on the surface of BP NSs has been firstly developed via electrostatic interaction. The resulted BP@MTX-HA NSs not only have good physical stability and photothermal conversion efficiency, but also exhibit the unique pH/NIR laser triggered release abilities. Besides, the temperature both in vitro and vivo could rise up to 45 °C or more within 3 min under 808 nm near infrared (NIR) irradiation (1.0 W/cm). Additionally, through the antitumor phototherapy efficacy investigation in 4T1 tumor-bearing BALB/c mice, BP@MTX-HA NSs exhibited significant inhibition on tumor growth and obvious superiorities over the single treatment of MTX chemotherapy or NIR photothermal therapy in terms of chemo-photothermal synergistic treatment and targeted co-delivery system. In conclusion, pH/NIR dual-triggered drug delivery system based BP NSs would be a prospective strategy in the chemo-photothermal medical fields through our preliminary assessments.