Fig. 1.

Schematic diagram of programmed combination therapy. Temperature responsive upconversion nanosystem (TR-UCNS), which contained photothermal agent (PdPc) and thermal responsive drug release unit (DPPC micelle), was built to perform programmed CT-PTT combination cancer therapy. By monitoring the microscopic temperature of TR-UCNS with upconversion luminescence (UCL), the power density of photothermal excitation source (730 nm laser) can be tuned accurately to initiate thermal-controlled drug release and photothermal therapy stepwise, thereby programming the combination therapy. Programmed combination therapy showed better therapeutic effect at a lower drug dosage than conventional combination therapy, from which the treatment modes were initiated simultaneously