Porphyrin-based covalent organic polymer as an effective and stable dispersed nano-quencher for rapid fluorescence sensing of nucleic acid

Abstract

An effective fluorescent quencher with high quenching efficiency and good stability is of great significance for fluorescence sensing of biomolecules, such as nucleic acid. Here, a porphyrin-based covalent organic polymer (PCOP) was fabricated by a coupling reaction between 1,3,5-triethynylbenzene and 5,10,15,20-tetrakis(4′-bromophenyl) porphyrin. A stable water dispersed PCOP with a porous sphere-like morphology around 50 nm and a zeta potential of −24.6 mV was obtained by using the sonication method. The PCOP showed a superb quenching efficiency and fast quenching dynamics to fluorescent dye due to the high specific surface area of PCOP, which enables the π–π stacking of fluorescent dye to the conjugated porphyrin surface of PCOP, leading to a static quenching effect. The excellent property of PCOP as a fluorescent quencher is comparable with graphene oxide, which is widely utilized in biomolecule detection. Thus, a sensing platform of PCOP for the rapid fluorescence detection of DNA from influenza A virus was constructed with high sensitivity and selectivity. The detection range was found from 1 to 30 nM for the target DNA with a detection limit of 0.38 nM. The effective and stable dispersed nano-quencher reported here highlighted the importance of covalent organic polymers for their sensing application.