Synthesis Of Water-soluble Polythiophene Derivatives And Study On Their Sensing Property

Fluorescent probes based on conjugated polymers have attracted widespread interest in biosensors due to their unique optoelectronic effects and good biocompatibility. Hitherto, the detection of small biomolecules is a problem to be solved for most of CP-based biosensors due to their simple structures and the weak interactions between them and CPEs. Among all kinds of conjugated polyelectrolyte, water-soluble poly(3-alkoxy-4-methylthiophene)s(P3RO-4Me T), whose derivatives conformation is sensitive to external stimuli, is not only easy to synthesis and functionalization, but also has the feature of colorimetric and fluorescent double responsiveness, which could realize the visualization of target analytes and detection of fluorescence dual mode.Adenosine triphosphate, ATP, is one of the important small molecules in biological body,and the establishment of a simple, rapid, sensitive and accurate ATP detection method not only promotes the research of the life process, but also has important practical significance in areas such as clinical diagnosis, drug analysis, drug development.Currently, the sensitivity and selectivity of ATP biological sensing system is not so desirable. Thus, in this paper we designed and synthesized a series of polythiophene derivatives with identification in the side chain, and studied their recognition and sensing properties of ATP. The specific contents and main results are summarized as follows:1. The synthesis and characterization of water-soluble polythiophene. We prepared polythiophene derivative monomers and corresponding copolymers by adjusting quaternary ammonium salt, anthracene and boric acid group into their side chains. And we characterized and confirmed their chemical structures by nuclear magnetic resonance(NMR), elemental analysis, mass spectra and gel permeation chromatography(GPC).2. The research on sensing properties of CPT-A which have quaternary ammonium salt and anthracene on it’s side chain. The electrostatic interaction between quaternary ammonium salt moieties in the side chain of CPT-A and the phosphate group can induce the conformational changes from planar to nonplanar, and then leading to the aggregation of the main chain of CPT-A, which result in red shift of UV-vis spectroscopy of CPT-A and distinct fluorescent quenching. In this process, the small amount of anthracene groups promote the aggregation of polythiophene backbones, and then accordingly enhanced the sensitivity of ATP detection dramatically.3. The research on sensing properties of CPT-B which have quaternary ammonium salt and boronic acid residues on it’s side chain. The electrostatic interaction between quaternary ammonium salt moieties in the side chain of CPT-B and the phosphate group and boronic acids moieties capable of reversible formation of strong covalent bonds withthe hydroxyl groups of diols to form cyclic boronate esters can bring about the conformational changes of polythiophenes, further caused red-shifts of UV-vis of CPT-B and apparent fluorescent quenching, realizing the high selectivity and sensitivity of ATP visual and fluorescent dual model detection.