2.4. Reactive oxygen species (ROS) and singlet oxygen (1O2) test in vitro

To verify the ROS generation potency, ptHDL/siNC-ICG and free ICG were added to 10 μM of DCFH or SOSG, and irradiated with an 808 nm laser (Meig Waei, China). In a feasible detection procedure, the DCFH was formed after a mixture solution containing methanol solution of DCFH-DA (0.5 mL, 1 mmol/L) and NaOH (2 mL, 0.01 mol/L) was under continuous stirring for 30 min shielded from light. Moderate sodium phosphate buffer (pH = 7) was placed into the above solution to make it to be neutral. The generated ROS and ¹O₂ were determined by measuring DCF (excitation = 488 nm) and SOG (excitation = 504 nm) fluorescence spectrum. The type of ROS produced by ptHDL/siNC-ICG were tested by an electron spin resonance spectrometer (ESR, E500, Bruker). ESR signals of radicals were trapped by 2,2,6,6-tetramethyl-4-piperidone (TEMPO) and recorded on a Bruker E500 electron paramagnetic resonance spectrometer.