Targeting of angiopoietin 2-small interfering RNA plasmid/chitosan magnetic nanoparticles in a mouse model of malignant melanoma in vivo

The aim of the present study was to observe the in vivo targeting characteristic of angiopoietin 2-small interfering RNA (Ang2-siRNA) plasmid/chitosan magnetic nanoparticles in an established nude mouse model of malignant melanoma (MM) under an external magnetic field. The nude mouse MM model was first established, then divided into 3 groups, including the control group, the non-targeting group and the target group, the control group was given normal saline and the non-targeting and targeting groups were administrated particles through the tail vein; the non-targeting group was not under external magnetic field and the control group and the targeting group were under external magnetic field for 60 min. The mice were then sacrificed and the tumor tissues were stained with hematoxylin and eosin and Prussian blue in order to verify the particle distributions in the tumor tissues. The control group exhibited negative Prussian blue staining in the tumor tissues, the non-targeting group demonstrated weakly positive Prussian blue staining in tumor tissues and the targeting group revealed strongly positive Prussian blue staining in tumor tissues. Ang2-siRNA plasmid vector/chitosan magnetic nanoparticles directly moved towards tumor tissues under the action of external magnetic field, thus it demonstrated good targeting characteristic.