Thymine-1-acetic Acid Functionalized Polydiacetylene Liposome For Visual Detection Of Pb²⁺

Polydiacetylene（PDA）has been widely used in optoelectronic devices and sensors because of its unique conjugated structure and outstanding optoelectronic properities.After adding various external stimuli to the system,the PDA can undergo a colorimetric transition from blue to red and a change from non-fluorescence to fluorescence.Not only UV-visible absorption spectrometers and fluorescence spectrometers can be used to easily detect optical changes but also can be seen with the naked eye.These properties make PDA an excellent material for platforms used to build chemical and biosensors.In recent years,many biosensors and chemical sensors based on the optical response of polyacetylene have been reported.These sensors enable the identification and analysis of analytes,including temperature,metal ions,anions,surfactants,amines,water,gases,sugars,hydrocarbons,neomycin,heparin,viruses,enzymes,bacteria and cancer.With the rapid development of science and technology and the advancement of society,the objects that need to be detected and analyzed slowly become diverse and of various natures.Therefore,in order to expand the identification target of the polyacetylene sensor and improve the performance of its detection and analysis,it is necessary to further develop a new type of excellent sensor based on polyacetylene materials,and to construct a polyacetylene recognition system with higher sensitivity and better recognition efficiency.Constantly expanding its detection target and detection performance is an inevitable direction for the development of this field.In this paper,we aim at construction of a new type of polyacetylene sensor,the typical heavy metal element Pb²⁺as the detection and analysis object.Through the reasonable design and synthesis of polyacetylene monomer,a sensing system based on polyacetylene functional components has been successfully constructed,and the efficient and sensitive identification and detection of Pb²⁺has been successfully realized.In order to expand the detection method of Pb²⁺and improve the detection performance of Pb²⁺based on polyacetylene sensor,we designed and synthesized thymine-1-acetic acid modified polydiacetylene monomer PCDA-TAA,and the polyacetylene liposomes sensor was prepared by PCDA-TAA and PCDA at the molar ratio of 1:9.The modified polyacetylene liposomes sensor can not only realize the colorimetric detection and fluorescence detection of Pb²⁺in aqueous phase,but also has excellent specificity for Pb²⁺.The experimental results show that the recognition mechanism of Pb²⁺may be that the strong complexation of thymine-1-acetic acid group and carboxy group to Pb²⁺stimulates the polyacetylene liposomes and then produces color changes and fluorescence enhancement.In summary,this study successfully designed and synthesized the modified diacetylene monomers,and prepared the polyacetylene liposomes.The conditions of the detection system are explored,optimized and improved.The successful detection of the sensitivity and selectivity of Pb²⁺in the aqueous phase was achieved by using this new type of polyacetylene sensor.In addition,this study also verifies the detection mechanism of the new type of Pb²⁺sensor,which provides a new design basis and guidance for the application in the field of polyacetylene sensor,and provides a new method and a new way for people to design a new type of sensor based on polyacetylene.