Synthesis And Performance Study Of Stimuli-responsive Targeted Nano Drug Delivery-multifunctional Imaging Systems

Malignant tumors are a global public health problem,and their incidence is increasing year by year.With the development of nanotechnology and tumor molecular biology research,the research of intelligent nano-targeting anti-malignant drug carriers is also in full swing,and has exerted great potential in the treatment of tumors.Semiconductor quantum dots are a new class of nanomaterials that not only achieve precise anti-tumor,but can also be used alone as bioluminescent probes.For example,ZnO quantum dots have attracted low attention in the biomedical field due to their low cost and low toxicity.ZnO quantum dots can be stably present in the environment of pH 7.4,but dissolve rapidly into Zn2+ions at pH<5.5.Therefore,controlled release and targeted drug delivery can be achieved according to the weak acidic environment of cancer cells.CdTe Quantum The point excitation spectrum is wide and continuous,the emission spectrum is narrow and symmetrical,the luminosity is high,and the photochemical stability is high,which can be well used for fluorescent labeling,and combines the targeted smart drug release with the bioluminescent label to form a drug delivery-imaging dual system.The diagnosis and treatment of a new system,thereby improving the therapeutic effect of cancer.The main research contents of the paper are as follows:1.A novel ZnO QDs macromolecular drug carrier was synthesized.Firstly,PPA and PEGMA were used as hydrophilic diblock copolymers by RAFT polymerization,and the polymerization target phenylboronic acid monomer was again initiated to form a triblock polymer.ZnO-COOH QDs were synthesized in ethanol,and then with amino groups.The polymer PEG-PPA-PBA forms a core-shell structure nanocarrier ZnO@?PEGMA-PPA-PBA?byreaction,andthenintroducesthioglycolic acid-protected CdTe quantum dots as a fluorescent imaging probe,and forms benzene afterloadingtheanticancerdrugDOX.Boricacid-targetedZnO,CdTe@?PEGMA-PPA-PBA?-DOX nanoparticles were studied for their release properties.The synthesis of ZnO-COOH QDs,CdTe,PEGMA-PPA-PBA,the formation of nanoparticles and their drug-loading properties were characterized by means of ¹H NMR,XRD,TEM and UV.The nanoparticle has pH dependence and exhibits good sustained release performance.CdTe is a fluorescent probe and has stable luminescence.It has great development prospects as an anticancer drug carrier and a bioluminescent probe.2.By modifying the polymer?PAH/SA-PEG-LA-PBA?),the ZnO quantum dots are used as the carrier,and the CdTe/CdS quantum dots are the nano drug carriers of the developer.Firstly,ZnO QDs and CdTe/Cds QDs were synthesized separately,and then the polyallyamine hydrochloride was modified to form a coordinable macromolecular polymer?PAH/SA-PEG-LA-PBA?).?PAH/SA-PEG-LA-PBA?)and quantum dots formed by coordination ZnO?CdTe/CdS@?PAH/SA-PEG-LA-PBA?)drug carrier.The drug-loading and release properties of the synthesized nano drug carrier and the determination of cytotoxic cell imaging were carried out to study its potential biological value.The synthesis of the polymer,the formation of the nano drug carrier and the release properties were characterized by means of ¹H NMR,TEM and UV.The drug-loaded carrier was characterized by fluorescence microscopy3.Based on the modifying of the polymer,DTPA was introduced to further synthesize a multifunctional drug delivery-imaging system platform using ZnO quantum dots as carriers,CdTe/CdS quantum dots as bioluminescent probes and radionuclide^99mTc as nuclear imaging.Firstly,the monomeric DTPA was synthesized,and the ZnO,CdTe/CdS@?PAA-His-PEG-PBA-DTPA?nanomedicine was formed by the coordination synthesis of polyacrylic acid?PAA-His-PEG-PBA-DTPA?and the coordination of ZnO and CdTe/CdS quantum dots.The carrier,the final sputum and the radionuclide ^99mTc form a comprehensive treatment system ZnO,CdTe/CdS@(PAA-His-PEG-DTPA-^99mTc-PBA).The water solubility and stability of the synthesized ZnO QDs nano drug carrier and the drug loading performance after DOX loading were determined by UV/Vis.Further study of its potential biological value such as cytotoxicity,fluorescent imaging,and small animal markers.