Construction Of Multifunctional Nanoparticles Based On DNA Bridging And Its Luminescent Properties And Killing Effect On Tumor Tissues

The purpose of this paper is to construct a long-circulating phospholipid material with single-stranded DNA as a bridge.In these particles,inorganic nano-silver ?AgNPs?and graphene quantum dots?GQDs?were adsorbed as nano-cores and external modification was employed to form a uniform and stable nano-preparation.The nano-preparation functions include inhibiting the proliferation of tumor cells in vitro,fluorescence imaging in tumor cells and inhibiting the growth of tumor tissues of tumor-bearing mice.Preparation of phospholipid coated multifunctional silver nano-preparation?ADG-DDP/ADG-DDPC?In this paper,a nanostructure system that targets anti-tumor effect was prepared,in which inorganic and organic bonds was synthesized according to the method reported in the literature.The silver nanoparticles were prepared by chemical reduction and sodium borohydride was used to reduce the silver atoms to the aqueous solution of silver nanoparticles in a simple state.The activated ssDNA was adsorbed on the surface of AgNPs and the GQDs were assembled onto the surface of the silver nanoparticles modified with ssDNA by using?-?bond stacking.Based on the phase conversion principle,different kinds of phospholipids were coated on the AgNP-DNA-GQDs?ADG?core.Two kinds of silver nano-preparation with tumor targeted long cycle?ADG-DDPC?and ordinary long cycle?ADG-DDP?were obtained.The properties of the nanoparticles were characterized by transmission electron microscopy?TEM?,ultraviolet-visible absorption spectroscopy?UV-Vis?,atomic force microscope?AFM?,Malvern particle size meter and inductively coupled plasma spectrometer?ICP-MS?.The nano-properties were visually observed by TEM and AFM.The particle shape was spherical,the particle size is about 30 nm and it did not change within 48 hours while stored in a refrigerator at 4?in the dark.The silver content in both nano-formulations were determined by ICP-MS which were about 20?g/mL.Mechanism of ADG-DDP/ADG-DDPC in HeLa cells and evaluation of its luminescence propertiesIn order to improve the stability of silver nano-preparation and achieve long-cycle active tumor targeting,this paper uses biocompatible synthetic phospholipids to encapsulateADG.After incubation of ADG-DDPC in H2O2 for a certain period of time,the fluorescence intensity of GQDs is directly proportional to the concentration of H₂O₂.In vitro cytotoxicity experiments showed that the IC₅₀values of ADG-DDP and ADG-DDPC were 270.85±0.07 ng/mL and 209.68±0.09ng/mL,respectively,indicating that ADG-DDPC has a stronger inhibitory effect on tumor cells.The inhibitory rate of intracellular lactate dehydrogenase of ADG-DDPC was significantly higher than that of ADG-DDP.ADG-DDPC promoted cells produced more reactive oxygen species than ADG-DDP.After ADG-DDP/ADG-DDPC were incubated in the tumor cells for 6 or 12 hours individually,the fluorescence pictures showed that the fluorescence intensity of ADG-DDPC was higher than that of ADG-DDP.In vivo evaluation of ADG-DDP/ADG-DDPC in tumor-bearing nude miceIn order to investigate their safety and effectiveness in vivo,We performed pharmacodynamic evaluation of mice.ADG-DDPC had a greater inhibitory effect on tumor tissues and has no significant difference from the commercially available paclitaxel injection for the reason that it had the targeting membrane peptides on surface.ADG-DDP also had a certain inhibitory effect on tumor tissues compared with the control group,while the inhibitory effect of ADG-DDPC was significantly higher than that of ADG-DDP group.The main organs of tumor-bearing mice at different time points after administration were harvested for tissue section toxicology study.ADG-DDP and ADG-DDPC had certain biological toxicity to tumor,heart,liver and kidney of mice.The tissue toxicity of ADG-DDPC to mice was obviously less than that of ADG-DDP group,for the reason that the silver content in tumor of tumor-bearing mice of ADG-DDPC group was about three times as high as that in ADG-DDP group at 6 hours after administration determined by ICP-MS.The in vivo experiments demonstrated that the ADG-DDPC group had a better anti-tumor efficacy.In this paper,a tumor targeting nano-silver preparation with high inhibition efficiency in vivo and in vitro was successfully prepared.The nano-formulation mainly relied on long-circulating phospholipids and targeted membrane peptides to deliver nano-silver into tumor cells,using high concentration H₂O₂ in tumor cells,to release the Ag⁺in the preparation to exert anti-tumor effect and to realize fluorescence imaging of GQDs in tumors.