Molecularly Imprinted Nanosensors For Tumor Markers Based On The Enhanced Effect Of Ionic Liquid

Ionic liquids are a sort of salts in the liquid state near room temperature.They possess excellent electrical conductivity,biocompatibility and water solubility.Their properties can be regulated by desiging the chemical structure of anions and cations.In this dissertation,imidazole was used as raw material to synthesize four novel ionic liquids:1-?3-mercaptopropyl?-3-vinyl-imidazolium tetrafluoroborate?MVIMBF4?,1,3-di?3-N-pyrrolpropyl?imidazolium bromine?DPIMBr?,1-?3-mercaptopropyl?-3-methyl-imidazole bromine?MIMBr?and 1-?N-pyrrolpropyl?-3-methyl-imidazole bromine?PMIMBr?.The chemical structures of these ionic liquids were confirmed by¹H-NMR,FT-IR and HPLC-MS.Subsequently,these ionic liquids were used as modifier,functional monomer and morphology control agent to prepar layered molybdenum disulfide nanosheets.Molecularly imprinted technology has made great progress in the recognition of small molecules.However,the imprinting of biological macromolecules is still facing great challenges.For example,biomacromolecules are unstable and easy to denaturalize and deactivate,functional monomers are hydrophobic,and template molecules are difficult to be removed and recognized.In order to solve these difficulties,using functionalized ionic liquids with good conductivity,biocompatibility and water solubility as functional monomers,surface molecularly imprinted polymerized ionic liquid film modified electrodes were prepared by electrochemical polymerization,and used for molecular imprinting sensors.The imprinting efficiency and rebinding rate of the imprinted film are both improved,leading to high sensitivity and selectivity for these imprinted sensors.The main contents of this dissertation are presented as following:?1?Gold nanoarrays were electrochemically deposited on a glassy carbon electrode?GCE?surface by using polycarbonate as template.1-?3-Mercaptopropyl?-3-vinyl-imidazolium tetrafluoroborate?MVIMBF4?ionic liquid was self-assembled onto the surface of gold nanoarrays to increase the conductivity and specific surface area of the electrode.Then,using 1,3-di?3-N-pyrrolpropyl?imidazolium bromine ionic liquid?DPIMBr?as a functional monomer and the neuron specificity enolase?NSE?as a template,a molecularly imprinted film was fabricated on the gold nanoarrays modified GCE.After removing the template,a NSE molecularly imprinted electrochemical sensor was obtained.The sensor showed high selectivity and sensitivity towards NSE,producing a linear response in the concentration range from 0.01 to 1.0ng mL^-1 and a detection limit of 2.6 pg mL^-1 with an incubation time of 15 min.The content of NSE in the serum of patients was detected.The result is consistent with that of ELISA,and the relative error is less than 5%.This metnod is simple,rapid,sensitive and selective for NSE determition,and possess potential applications in clinical diagnosis.?2?Using 1-?3-mercaptopropyl?-3-methyl-imidazole bromine ionic liquid?MIMBr?as a sulfur source and a morpho control agent,sodium molybdate?Na₂MoO₄?as a molybdenum source,a small lamellar MoS2 was prepared by hydrothermal method.The gold nanoparticles were grown on the surface of the layered MoS₂ by wet chemical method to obtain AuNPs/2D-MoS₂ nanocomposites.The nanocomposites were used to modify the glassy carbon electrode.Then,the 1-?N-pyrrolpropyl?-3-methyl-imidazole bromine ionic liquid?PMIMBr?was used as a functional monomer and the progastrin-releasing peptide?Pro-GRP?was used as a template and electrochemical polymerization was used to construct a Pro-GRP photochemical molecularly imprinted sensor.In the range of 20 pg mL^-15 ng mL^-1,the sensor shows a good linear relationship between the photocurrent variation before and after the rebinding of Pro-GRP and the concentration of Pro-GRP.The detection limit was calculated to be 3.2 pg mL^-1?S/N=3?.