Preparation Of Ruthenium Complex Functionalized Gold Nanoparticles And Its Biological Activity

To reduce the mortality induced by cancer,scientists have developed a variety of anticancer drugs.The discovery of cis-platinum that could be used as anticancer drug had greatly promoted the research on the platinum complexes,which resulted in the widely used of them to cure cancer clinically.However,there were lots of side effects such as nephrotoxicity,neurotoxicity and drug resistance when platinum complexes were used in the therapy of cancer,which made people focus their attention on developping other anticancer drugs that own better therapeutic effects than platinum complexes but less side effects.Ruthenium complexes have stable chemical structures and remarkable physicochemical properties,which have potential to become outstanding anticancer drugs.Ruthenium complexes have six-coordinated with octahedron structures and the alterability of their ligands make them suitable for many designs.However,ruthenium complexes have poor ability to pass the membrane of cells,which limits the application of them to used as anticancer drugs.As we all know,gold nanoparticles,which can be used as drug carrier,fluorescence imaging and biological probe,have been widely used in biomedical field because of their unique physicochemical properties and good biocompatibility.Thus,we can try our best to use ruthenium complexes functionalized gold nanoparticles via a specific way,which can put the remarkable properties of ruthenium complexes and gold nanoparticles together so that to improve their bioactivity.This article mainly introduced the synthesis of gold nanoparticles,the way of ruthenium complexes modified gold nanoparticles and their bioactivity.Specific contents are as follows:1.Gold nanoparticles had been synthesized by sodium citrate reduction method.To improve the stability of gold nanoparticles,some mercapto ligands were chosen to modify them.Two kinds of PEG,which included HS-PEG2000 and LA-mPEG5000,as well as mercaptoethylamine,mercaptopropionic acid and cysteine,were selected to modify gold nanoparticles to improve the stability and function of them.The stability of gold nanoparticles modified by different mercapto ligands was measured by UV spectrophotometer,Zetas potentiometer and Nano laser particle size analyzer.Results showed that double ligands LA-mPEG5000 and mercaptoethylamine were most suitable to use to stable and modify gold nanoparticles,for LA-mPEG5000 could improve the stability of gold nanoparticles while mercaptoethylamine could modify active groups on the surface of gold nanoparticles which could facilitate their subsequent application.Gold nanoparticles modified with LA-mPEG5000 and mercaptoethylamine had outstanding stability no matter when they were in different concentrations of salt solution or different pH values of Tris buffer.2.[Ru(OPDA)(4-CTPY)NO]3+(Ru-NO)that had potential to be acted as an antitumor drug could be reacted with gold nanoparticles by amidation reaction via the carboxyl group of Ru-NO and the amino group on the surface of gold nanoparticles that modified by mercaptoethylamine to form a system of Au-Ru-NO.Gold nanoparticles functionalized with Ru-NO were characterized by UV spectrophotometer and infrared spectroscopy to ensure that the system of Au-Ru-NO was successfully built up.The ratio of ruthenium and gold of Au-Ru-NO was 328:1,which was characterized by mass spectrometer.The excellent physicochemical properties of ruthenium complex and gold nanoparticles were put together through the combination of ruthenium complex and gold nanoparticles,which could improve their biological activity and promote a better application.3.Through amidation reaction,Ru-NO had successfully functionalized gold nanoparticles and their bioactivity were studied by different cytological methods.By MTT cytotoxic method,we could know the cytotoxicity of Ru-NO toward Hep-2 cells was about 8 ± 2 ?M while that of Au-Ru-NO was about 17 ± 2 ?M,which indicated that the cytotoxity of ruthenium complex was reduced after being functionalizied gold nanoparticles.We then explored the apoptotic mechanism by cell apoptosis method,the determination of reactive oxygen species,mitochondrial membrane potential and western blot.It was found that Ru-NO induced the apoptosis of Hep-2 cells by increasing the content of reactive oxygen species and decreasing the mitochondrial membrane potential while it down regulated the Bcl-2 protein and up regulated the p53 and Bax protein as well.However,Au-Ru-NO could also increase the content of reactive oxygen species and decrease the mitochondrial membrane but the degree of which was less than Ru-NO.Au-Ru-NO could down regulate p53 protein and up regulate Bax protein to induce cell apoptosis.Results showed that Au-Ru-NO could not only induce the apoptosis of Hep-2 cells,but also reduce the systemic toxicity,which indicated that Au-Ru-NO could be acted as a potential anticancer drug.What's more,we could know that Ru-NO and Au-Ru-NO mainly located in the cytoplasm by the observation of laser confocal microscopy.