鈥淗igher Energy Gap鈥?Control in Fluorescent Conjugated Polymers: Turn-On Amplified Detection of Organophosphorous Agents

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• 作者：Deepa Pangeni ; Evgueni E. Nesterov
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：September 24, 2013
• 年：2013
• 卷：46
• 期：18
• 页码：7266-7273
• 全文大小：422K
• 年卷期：v.46,no.18(September 24, 2013)
• ISSN：1520-5835

文摘

Chemo- and biosensors based on fluorescent conjugated polymers benefit from greater detection sensitivity due to amplification of the electronic perturbations produced by analyte binding. This amplification stems from the exciton-transporting properties of conjugated polymers. In a conventional sensor design paradigm, excitons migrate from the bulk of the polymer to the analyte binding sites which can be either fluorescence quenching sites (turn-off sensors) or lower energy fluorophores (turn-on sensors). Herein, we proposed an alternative design paradigm when analyte binding creates a higher energy gap site in the polymer backbone. In the case of isolated polymer chains in dilute solution, these higher energy gap sites act as 鈥渞oadblocks鈥?for migrating excitons, effectively limiting the exciton migration length. This is responsible for an amplified enhancement of fluorescence of the conjugated polymer sensor. As a proof of concept, we utilized this design principle to develop an amplifying turn-on sensor for organophosphorous warfare agents mimics and demonstrated substantial signal gain and much broader analyte detection range relative to the corresponding small-molecule analogue. This new paradigm expands the generality and universality of the signal amplification concept in conjugated polymers and can be used to design amplifying turn-on fluorescent sensors for various practically useful analytes.