Surface Functionalization Of Gold And Silver Nanoparticles And Their Preliminary Applications In Detection And Treatment Of Thrombosis

Thrombosis is a pathological process which seriously threatens human health. It is closely related to many diseases such as tumor, infectious diseases, trauma and obstetric accident, etc. Many diseases were able to be cured with the development of science and technology. However, the prevention and treatment of thrombosis is still far failed to achieve the desired goal. For the detection of prethrombotic state, a series of molecular markers has been found, but the detection methods are stagnant. Meanwhile, researchers found that some natural anticoagulation agents have showed great potential in the prevention and treatment of thrombosis such as rutin. These agents generally have a systematic function and low incidence of adverse reactions, but their further applications are limited by their low bioavailability and solubility. Recently, gold and silver nanoparticles(Au and Ag NPs) are widely used in medical diagnosis and therapy based on their unique optical properties, size effect and good biocompatibility. Meanwhile, the functionalizations of Au and Ag NPs have extended their application fields. Therefore, in this study, heparin was immobilized on the surface of Au NPs via Au-S bond for thrombosis detection, as well as rutin was fixed on Ag NPs to prevent the thrombogenesis. Their applications were discussed as below:(1) Preparation of heparin-modified Au NPs for human antithrombin III detection.Heparin-modified gold nanoparticles(Hep-Au NPs) was prepared by immobilizing heparin on the surface of Au NPs. Based on the specific recognition between heparin and AT-III, they could be used for antithrombin III(AT-III) detection. Four kinds of Hep-Au NPs of different average size were prepared, and TEM observation showed their average size were 15 nm, 41 nm, 66 nm and >100 nm, respectively, with well-dispersed nature. Meanwhile, TGA results showed that the immobilized amount of heparin were 24.95%, 23.90%, 22.64% and 19.32% on each kind of Hep-Au NPs. By comparing the detection results, it was found that the UV-vis absorption of Hep-Au NPs(15 nm) at 531 nm had optimal linearity against the concentration of AT-III ranging from 1 to 26 μmol/L. The detection limit is 0.003 μmol/L(3σ), the coefficient correlation(R2) is 0.996 and the method is repeatable. This novel Hep-Au NPs is promising to be used for clinical AT-III detection.(2) Preparation of p H and glucose-responsive Rutin-coated Ag NPs for antithrombus.By using polyvinylpyrrolidone(PVP) as the protective agent, Ag NPs were prepared. Then, rutin was combined on the surface of Ag NPs. The Rutin-Ag NPs were well-dispersed in water. The morphology study showed that the particle size, size distribution and morphology have no obvious change before and after the modification. The amount of immobilized rutin were measured to be 12.5%(wt%). In addition, the Rutin-Ag NPs were well-dispersed in the solution containing serum, showing good blood compatibility. The p H and glucose-responsive release behavior of rutin was measured in vitro, and the release period lasted 144 h. The cytotoxicity assay showed that Rutin-Ag NPs had non-significant cytotoxicity against HUVEC cells, and the cell cytotoxicity is decreased obviously after the modification of Rutin. Besides, the in vitro anticoagulation experiments showed Rutin-Ag NPs had good anticoagulant activity. Mice tail thrombosis model showed that Rutin-Ag NPs could inhibit thrombosis effectively with reduced risk of bleeding.