Preparation Of Aggregation-Induced Emission Amphiphilic Molecule-DNA Complex And Its Luminescence Analysis Application

Photosynthesis absorbs sunlight energy through the light harvesting systems(LHSs),and then effectively transfers it to the reaction center to generate enough biomass energy to sustain life on earth.LHSs in nature has a sophisticated supramolecular composite structure,usually with more than 200 closely arranged antenna chromophore donors and a reaction center acceptor.In order to imitate efficient artificial LHSs,the general strategy is to co-assemble energy donors and energy acceptors into a framework with a high donor/acceptor ratio,such as amphiphilic molecular aggregates,metal-organic frameworks,natural and customized double-stranded DNA,protein,etc.However,these frameworks usually provide equivalent binding sites for the donor and acceptor,leading to the problem of a large total donor/acceptor ratio and a small local ratio,thereby reducing the actual energy transfer efficiency.Based on this,in this paper,three new types of aggregation-induced emission(AIE)amphiphilic molecule were designed and synthesized by introducing tetraphenylethylene(TPE)luminophore and changing the position of the cationic head group on the molecular skeleton of decyltrimethylammonium bromide(C10TAB).Using natural double-stranded DNA as the LHSs framework,the co-assembly behavior of AIE amphiphilic molecules and double-stranded DNA was controlled by electrostatic interaction,and an artificial LHSs with high antenna effect was successfully constructed in aqueous solution.The main research contents are as follows:1.Under the condition of keeping the same number of C10TAB hydrophobic chain alkyl groups,by changing the position of the cationic head group to adjust the hydrophilic lipophilic balance(HLB),three AIE amphiphilic molecules with terminal modified TPE luminophore were designed and synthesized:TPE-C2DABC8,TPE-C6DABC4 and TPE-C10TAB.The structural information of AIE amphiphiles was characterized by proton nuclear magnetic resonance,carbon nuclear magnetic resonance spectroscopy and mass spectrometry,and the basic optical properties of AIE amphiphiles were explored through ultraviolet-visible absorption spectroscopy and fluorescence tests.The results show that they all have significant AIE characteristics,and TPE-C10TAB has good water solubility and high fluorescence performance in the same concentration range.2.Preferably,TPE-C10TAB is used as a donor molecule for LHSs,and is co-assembled with double-stranded DNA through electrostatic interaction to form a TPE-C10TAB-DNA assembly.Through conductivity measurement and fluorescence spectrum test,the optimal binding concentration of TPE-C10TAB and double-stranded DNA was determined.The energy transfer process and light harvesting performance of the TPE-C10TAB-DNA assembly loaded with different concentrations of fluorescent acceptors were measured by fluorescence decay curve and composite fluorescence spectroscopy.The interaction mechanism between fluorescent acceptor molecules and double-stranded DNA,and TPE-C10TAB and double-stranded DNA were studied by circular dichroism and surface potential testing.In addition,the versatility and practicality of the TPE-C10TAB-DNA assembly was verified.