Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
Department of Chemistry, University of Houston, Houston, Texas 77204, United States.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10959-10972. doi: 10.1021/acsami.9b21970. Epub 2020 Feb 18.
A novel amphiphilic aggregation-induced emission (AIE) copolymer, that is, , consisting of -isopropylacrylamide (NIPAM) as a hydrophilic unit and a tetraphenylethylene-spiropyran monomer () as a bifluorophoric unit is reported. Upon UV exposure, the close form of non-emissive spiropyran (SP) in can be photo-switched to the open form of emissive merocyanine (MC) in in an aqueous solution, leading to ratiometric fluorescence of AIEgens between green TPE and red MC emissions at 517 and 627 nm, respectively, via Förster resonance energy transfer (FRET). Distinct FRET processes of can be observed under various UV and visible light irradiations, acid-base conditions, thermal treatments, and cyanide ion interactions, which are also confirmed by theoretical studies. The subtle perturbations of environmental factors, such as UV exposure, pH value, temperature, and cyanide ion, can be detected in aqueous media by distinct ratiometric fluorescence changes of the FRET behavior in the amphiphilic . Moreover, the first FRET sensor polymer based on dual AIEgens of TPE and MC units is developed to show a very high selectivity and sensitivity with a low detection limit (LOD = 0.26 μM) toward the cyanide ion in water, which only contain an approximately 1% molar ratio of the bifluorophoric content and can be utilized in cellular bioimaging applications for cyanide detections.
一种新型的两亲聚集诱导发光（AIE）共聚物，即 ，由 -异丙基丙烯酰胺（NIPAM）作为亲水单元和四苯基乙烯-螺吡喃单体（）作为双荧光团单元组成。在紫外光照射下，可溶液中，非发光型螺吡喃（SP）的闭合形式可光致转换为发射型开环体（MC），导致 AIEgen 的比率荧光分别在 517nm 和 627nm 处从绿色 TPE 到红色 MC 发射，这是通过Förster 共振能量转移（FRET）实现的。在各种紫外光和可见光照射、酸碱条件、热处理和氰离子相互作用下，可以观察到 的明显 FRET 过程，这也得到了理论研究的证实。在水相介质中，可以通过 AIE 两亲物中 FRET 行为的明显比率荧光变化来检测环境因素（如紫外光照射、pH 值、温度和氰离子）的微小扰动。此外，还开发了基于 TPE 和 MC 单元双 AIEgen 的第一个 FRET 传感器聚合物 ，对水中的氰离子具有非常高的选择性和灵敏度，检测限（LOD=0.26μM）低，仅含有大约 1%摩尔比的双荧光团含量，可用于细胞生物成像应用中的氰化物检测。
