A Selective Colorimetric Sensor for Pb2+ Detection by Using Phenylboronic Acid Functionalized Polydiacetylene Liposomes

Due to the high toxicity for brain and the nervous system of humans and other living organisms, the design and fabrication of a robust and sensitive method for the detection of Pb2+ in the aqueous solution has attracted the increasing attention among scientists. Herein, a colorimetric and fluorometric sensor for the detection of Pb2+ in the aqueous solution by incorporating a new phenylboronic acid functionalized polydiacetylene liposome was designed. The molar ratio of 4:1 between the monomers, 10,12-pentacosadiynoic acid (PCDA) and phenylboronic acid functionalized PCDA (PCDA-pBA) not only offered sufficient binding sites for Pb2+, but also interrupted the efficient π-conjugation backbone of polydiacetylene (PDA) chains associated with the color and fluorescence changes. Compared with other metal ions, only Pb2+ could cause the color change and the fluorescence enhancement. Moreover, the hybrid PDA liposomes exhibited high sensitivity, fast response time (10 s), and a reasonable detection limit for Pb2+ (0.1 µM). This work not only provides a versatile methodology for the fabrication of sensors for Pb2+ detection, but also is of great fundamental value for a deeper understanding of the complexion-induced color changes based on polydiacetylene materials, and may pave the way for fabrication a new method for recognizing other metal ions.