A Study On Interaction Between Organic-inorganic Hybrid POM And DNA

Polyoxometale(POM)of Anderson type is a polyatomic ion,used as building block as nanostructure and allows modification.When we modified the Anderson POM with alkyl chain,the hybrid would self-assemble into different structures.When we modified it with biolignd,the hybrid could be a candidate of antitumor drug.Generally speaking,the organic molecule functionalities would determine the functionalities of hybrid and its self-assembly and application.Organic molecule binding to the POM covalenty not only make the POM more stable but also.can utlize of the synergestic effect between the oganic part and inorganic part.So in this paper,our purpose is to select organic molecule and modify POM with it and make the hybrid get the functionalities of organic part.In this paper,there are two main parts: 1.We select three small organic molecules which can intercalate into DNA base pairs.The charecteristics of organic molecule should fulfill the points : strong interaction with DNA and easy to be modified.By referring to literatures,we choose the 9-anthracene methanol,3-nitro-1,8-naphthalenedicarboxylic anhydride,naphthalene-1,4,5,8-tetracarboxylic dianhydride as the ligand.These three molecule easy to be covalenty modified to Anderson type POM with the linker: succinic anhydride and 3-aminopropionic acid.Then we synthesized three organic-inorganic hybrids successfully.We use Nuclear magnetic resonance(NMR),Infrared spectroscopy(IR),elemental analysis(EA),thermogravimetric analysis(TGA)to characterize three hybrids: POM-1,POM-2,POM-3.2.In this part,the main purpose is to detect the interaction between the organic-inorganic hybrid and the DNA.So we used the UV-visible,circular dichroism and fluorescence spectrometer in phosphate buffer to detect the interaction between the DNA and the POM hybrid,also accessed how this interaction could influence the secondary structure of the DNA.Based on these results,only POM-3 can realize the idea which the organic part can intercalte into the DNA base pair,this interaction can resist the electrostatic repulsion between POM and DNA backbone.Then we focused on POM-3.we used NMR,ITC,TEM,AFM these methods to further confirm this non-covalent interaction between POM-3 and double helix DNA by chemical shifts,thermodynamic constants and morphology.At last,we make a summary and expectation of the work in this paper: we have successfully single side modified Anderson POM(AlMo6)with small organic molecule,named POM-1,POM-2,POM-3.Only POM-3 has the ability to intercalate into DNA base pair and this non-covalent interaction is strong according to the ITC result.Based on this modification idea we expect that we can change the POM or organic part with special function,like catalysis and antitumor.Try to develop potential application of the POM hybrid in functional self-assemmbly,medicine and materials.