ABSTRACT
Objective To detect the relaxation property of mesoporous silicananocapsules loaded liposomes (MSN-LIPO), and to explore their functions of enhancing MRI T2 weighted imaging. Methods In vitro, MSN-LIPO with different ironconcentrations were scanned by MRI system to detect their relaxation properties. In vivo, six BALB/c nude mouse models with subcutaneous malignant glioma were established and randomly divided into two groups, which were injected with the same concentration of MSN-LIPO intratumorally and intravenously, respectively. The mice in the two groups were scanned by MRI before and after injection, and the image characteristicswere studied and the signal intensity of tumors was statistically analyzed. Results In vitro MRI imaging showed that the signal intensities of the images were gradually decreased with the increase of iron concentrations in MSN-LIPO, and 1/T2 had a good linear relationship with the concentration within a certain range, with the relaxation rate (r2) being 413.7 mmoL-1 s-1. MRI imaging of BALB/ c nude mouse models with malignant glioma showed that the signal intensity of the tumor after intratumor injection of MSN-LIPO was significantly lower than that before intra-tumor injection (15.34±1.24 vs 211.44 ± 5.34, t=36.38, P < 05), and the signal intensity of the tumor after intravenous injection of MSN-LIPO was significantly lower than that before intravenous injection (179.00 ± 4.35 vs 235.99 ± 5.17, t=14.34, P <0.05). Conclusion MSN-LIPO has good magnetic relaxation property and good MRI T2 weighted contrast enhancement function in vivo, suggesting that it can be used as a MRI T2 contrast agent.
ABSTRACT
Objective To prepare and characterize a thermo-sensitive liposomes co-loaded with IR-780 and doxorubicin (D0X). Methods Membrane hydration method and ammonium sulfate gradient method were used to prepare IR-780/D0X thermo-sensitive liposomes (DITSL). The particle size, zeta potential and polydispersity coefficient (PDI) of liposomes were measured by Malvern laser particle size analyzer, and the drug release characteristic of DITSL induced by laser was also detected. Results DITSL loading both IR-780 and D0X was successfully prepared. The encapsulation efficiency of IR-780 and D0X was (94.47 ± 8.57) % and (92.52 ± 7.61)%, respectively; the average particle size was (138.98 ± 8.74) nm, with slight negative potential; the PDI was 0.32 ± 0.02. The drug release rate of DITSL was about 80.1% after laser radiation (0. 8 W/cm2, 5 min) and the highest temperature of DITSL was 54.2°C. Conclusion The prepared DITSL has high drug encapsulation efficiency, appropriate particle size, high photo-thermal conversion efficiency, good temperature sensitivity and laser-induced thermal drug release property, which lays a foundation study for the combination treatment of tumors with photo-thermal therapy and chemotherapy.