The Preparation Of Aqueous AgInS/ZnS Quantum Dot And Its Application As A Gene Vector

Gene therapy has been extensively studied as a very promising therapeutic approach.A gene vector is of great importance to deliver gene into the targeted cells efficiently which usually cannot be achieved by a naked gene.Thus developing a safe and effective gene delivery vehicle is the main study of gene therapy.Cationic polymeric gene delivery systems,such as polyethylenimine(PEI),have great application prospect,which could achieve quite high transfection efficiency.But the high cytotoxicity of the high molecular PEI severely limits further clinical application.Since the polymeric gene delivery mechanism is unclear up to now,polymeric gene vectors often visualize their intracellular delivery pathway by labeled with kinds of fluoresceins.However,the fluoresceins attached to the polymeric gene vectors may change the physicochemical properties of the original vectors.Therefore,it is very urgent to develop a kind of self-fluorescent label-free gene vector with high gene transfection efficiency and low cytotoxicity.Meanwhile,I-III-VI QDs,such as AgInS,are of particular interest for bioimaging area due to the unique optical properties and low cytotoxicity.In this paper,we synthesized PEI-capped AgInS/ZnS(ZAIS)QDs in aqueous solution with PEI as a surface stabilizer.The as-prepared ZAIS QDs was used for gene delivery,and visualized the intracellular delivery pathway.First,we adopted one-pot mode prepared the PEI-capped ZAIS QDs with the PEI and mercaptopropionic acid(MPA)as surface stabilizers.The emission wavelength of ZAIS QDs can be tuned ranging from557 nm to 715 nm when controlling the reaction conditions.The as-prepared ZAIS QDs had high photoluminescence intensity and good colloidal stability,which made it suitable for biolabeling and bioimaging.Second,the as-prepared ZAIS QDs mixed with EGFP plasmid DNA to form the QDs/DNA complexes.The physicochemical properties of the complexes were measured to testify the ability of ZAIS QDs condensing the DNA.The good biosafety of the ZAIS QDs was verified by MTT assay and hemolysis assay.The ZAIS could mediate plasmid DNA delivery into HeLa cells with the high transfection efficiency of 40%,meanwhile allowing the real-time monitoring of gene transfection.The as-prepared ZAIS QDs were verified as useful self-tracking gene vectors,which integrated gene delivery with bioimaging functions without external labeling.