HNTs/siRNA preparation and characterization

HNT aqueous solution preparation: 1.0 g of halloysite ore was processed for 90 s using high-speed crushing, 400-mesh sieving, 25-min ultrasound, and differential centrifugation (5 min at 3000 rpm and 10 min at 9000 rpm), and then centrifuged for 5 min at 10,000 rpm. The microstructure of the HNTs was characterized using scanning electron microscopy (TESCAN MIRA3 LMU), transmission electron microscopy (JEOL JEM-200CX), x-ray diffraction (DX-2700), and Fourier transform infrared spectra (Nexus 670).

siRNA loading: 30 μl of HNT aqueous solution (3 mg/ml) was mixed with 12 μl of siRNA solution [1 OD unit of siRNA was dispersed into 125 μl of DEPC (diethyl pyrocarbonate) water], vacuum impregnated for 3 hours, and then centrifuged for 5 min at 10,000 rpm. The siRNA loading efficiency was evaluated by gel electrophoresis of the supernatant.