Conjugated Polymer: Synthesis, Characterization And Application In Sensors

In recent years, the study of conjugated polymers (CPs) has attracted a lot of attentions. Asspecial macromolecular materials, CPs have not been only employed in light-emitting devicesbut also used as transducers in sensor applications to measure and amplify different signals inelectrochemical biosensors, fluorescence biosensors, and metal-ion sensors. Conjugated CPscontain alternating single and double bonds in their polymer chain resulting in the formation ofde-localised electrons which act as charge carriers.The delocalization of π-electrons occurringin the conjugated molecules can lead to signal amplification properties.Low cost, scalability,easy processing capability and material properties makes conducting polymers attractivecandidates for applications in chemical biosensing.Detecting small quantities of biomolecules is paramount in the diagnosis of diseases suchas cancer and for real time monitoring of important blood analytes such as glucose. A majordriving force for the integration of natural biomolecular recognition elements into sensors istheir exquisite selectivity to specific analytes. Biosensors utilizing CPs, as a component in thinfilms, have been utilized for sensing both large and small biomolecules.According to the application study of CPs in chemical biosensing, the main research is asfollows:1. A novel water-soluble polyfluorene derivative, poly[(9,9-bis(3’-((N,N-dimethylamino)N-ethylammonium)propyl)-2,7-fluorene)-alt-2,7-(9,9-p-divinylbenzene)] Dibromide (P-2)was synthesized by the palladium-catalyzed Suzuki coupling reaction. In addition, P-2features charged side groups and subsequently good water solubility. Moreover its strongfluorescence has been successfully applied to the determination of BSA.2. Thin films of molecularly imprinted sol-gel polymer with specific binding sites fortrichlorfon were prepared, which were fixed on glassy carbon electrodes and used asrecognition material. A novel electrochemical sensor for determination of trichlorfon wasdeveloped based on the reaction between trichlorfon and the molecularly imprinted sol-gelfilms.3. A novel amino-functionalized polyfluorene derivative have been successfullydesigned and synthesized. On the basis of its electroluminescence, the polyfluorene derivative was chemically immobilized on an ITO glass surface as the work electrode, and an ECLlabel-free immunosensor for sensitive detection of cancer biomarker CA125as a model detectsystem was proposed.4. Electrogenerated chemiluminescence (ECL) of a novel phenyleneethynylenederivatives (4,4’-(2,5-dimethoxy-1,4-phenylene)bis(ethyne-2,1-diyl) dibenzoic acid)(P-acid)and its first immunosensing application were studied by immobilizing P-acid on an silicaglass to fabricate fluorescence immune sensor for sensitive detection of carcinoembryonicantigen (CEA).