Preparation And Computational Simulation Of Molecularly Imprinted Polymers With Optical And Electrochemical Properties

Molecularly imprinted polymer is a kind of manmade high molecular polymerswith bio-specific recognition. They are synthesized by the copolymerization ofcrosslinking agent in the presence of tempalate molecules and monomers. Afterpolymerization, removal of the template molecules with proper methods leaves thecomplementary recognition sites that selectively rebind template molecules on size,shape and functionality. Their applications in chemical sensors attract much attentionfrom lots of research fields. In a chemical sensor, molecularly imprinted polymeracts as recognition part, which connects with transition part of the sensor. Thedetection is accomplished on the base of specific characteristics of the target analyte(such as its IR spectrum/fluorescence/electrochemical activity) or modification ofphysic-chemical parameters of the system in response to the binding with thetemplate. The synthesis of molecular imprinted polymer is usually experimental, andthere is no clear mechanism now. Recent years, with the development of computertechnology and quantum-mechanical theory, the application of computer modelingtechnique into the design and research of molecularly imprinted polymer are moreand more extensive. Computer modeling technique provides a potential method topredict some performance and behavior of the molecularly imprinted polymer.In this study, we used computer modeling technique to study the molecularinteraction between template and monomer and predict the mole ratio of the templateand monomer in some reaction. Then, we used sol-gel polymerization andelectrochemical synthesis method to obtain a molecularly imprinted optical sensorand three molecularly imprinted electrochemical sensors. The innovative aspects ofthe paper are as follows:1. The current situation and development related to molecularly imprintedpolymers with optical and electrochemical properties are reviewed.2. A magnetic molecularly imprinted fluorescent sensor for sensitive and convenient determination of ciprofloxacin or norfloxacin in human urine wassynthesized and characterized by scanning electron microscopy, fourier transforminfrared spectroscopy, X-ray diffraction, ultraviolet-visible spectroscopy andfluorescence spectroscopy. Both cadmium telluride quantum dots and ferroferricoxide nanoparticles are introduced into the polymer for rapid separation anddetection of the target molecules. The synthesized molecularly imprinted polymerswere applied to detect ciprofloxacin or its structural analogous norfloxacin in humanurine with the detection limit130ng mL-1. A computational study was developed inorder to evaluate the template-monomer geometry and interaction energy in thepolymerization mixture to determine the reaction mole ratio of the template andmonomer molecules.3. Resorcinol was used as monomer and triclosan was used as templatemolecule, a molecularly imprinted electrochemical sensor was obtained throughcyclic voltammetry electro-polymerization. Computational simulation was applied tomodel the configuration of the template-monomer complex and calculate the bindingenergies of complex. The preparation conditions of molecularly imprinted sensorwere discussed to optimize the synthetic conditions and the electrochemical sensorwas prepared at the optimal conditions. Indirect method was applied to detecttriclosan in the potassium ferricyanide probe solution with the linear scope1.7～6.7ng/mL and the detection limit1.5×10-7ng/mL.4. Resorcinol and o-phenylenediamine were used as composite monomers andtriclosan was used as template molecule, a molecularly imprinted electrochemicalsensor was obtained through cyclic voltammetry electro-polymerization.Computational simulating was applied to model the configuration of thetemplate-monomer complex with single and composite monomers and calculate theirbinding energies. The preparation conditions of molecularly imprinted sensor werediscussed to optimize the synthetic conditions and the electrochemical sensor wasprepared at the optimal conditions. Indirect method was applied to detect triclosan inthe potassium ferricyanide probe solution with the linear scope1.7～10.0ng/mL and the detection limit4.1×10-7ng/mL.5. Pyrrole was used as monomer and ascorbic acid was used as templatemolecule, a molecularly imprinted electrochemical sensor was obtained throughcyclic voltammetry electro-polymerization on a flexible carbon cloth electrode.Computational simulating was applied to model the configuration of thetemplate-monomer complex and calculate the binding energies of the complex. Thepreparation conditions of molecularly imprinted sensor were discussed to optimizethe synthetic conditions and the electrochemical sensor was prepared at the optimalconditions. The molecularly imprtied electrochemical sensor can detect ascorbic acidwith the linear scope0.96～7.8mM and the detection limit8.6×10-5M.