Sensitive Colorimetric Sensor for Lead Ions and VOCs Based on Histidine-Functionalized Polydiacetylene

Abstract

Due to the high toxicity of lead ions (Pb2+) and volatile organic compounds (VOCs) to human health and the environment, increasing attention has been paid by scientists to the development of simple, flexible and sensitive sensors or methods that are capable of tracing Pb2+ ions or VOCs with colorimetric visualization. In this study, the fabrication of colorimetric sensors based on histidine-functionalized diacetylene (His-DA), chromatic π-conjugated liposomes, for tracing Pb2+ ions was described. With a suitable molar ratio (4:1) between the10,12-pentacosadiynoic acid (PCDA) and His-DA monomers, the histidine units of the hybrid liposomes could rationally interrupt the efficient backbone length of polydiacetylene (PDA) chains, which causes the probe to be highly sensitive and selective for colorimetric visualization of tracing Pb2+ ions. Moreover, the His-PDA films also displayed sensitivity to volatile organic solvents or vapors, which could promote vivid color changes from blue to purple or pink. These interesting findings indicate that histidine-functionalized diacetylene may offer a promising way to design smart devices for real applications of sensing or tracing hazardous substances in the future.