Three kinds of porphyrin dots as near-infrared electrochemiluminescence luminophores: Facile synthesis and biosensing

Abstract

Three kinds of porphyrin dots, including TCPP dots, ZnTCPP dots and TCPP-based metal organic framework (pMOF) dots, have been subtly synthesized for the first time by a universal straightforward exfoliation of bulk porphyrin aggregates or pMOF. To explore their ECL application, a novel label free “signal-on” ECL biosensor for ultrasensitive detection of Pb 2+ was developed based on TCPP dots as DNA intercalators and DNAzyme-based hybridization chain reaction signal amplification. • Three kinds of porphyrin dots are subtly prepared by a simple and universal exfoliation. • The novel porphyrin dots show excellent annihilation ECL activity. • They all exhibit stable and robust near-infrared co-reactant ECL performance. • A label free ECL biosensor is established for trace Pb 2+ detection based on TCPP dots. • The porphyrin dots as ECL emitters give a new proof of concept. Exploring novel near-infrared (NIR) luminophore with highly efficient and benign is strongly anticipated for electrochemiluminescence (ECL) evolution. Here, three kinds of porphyrin dots including 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) dots, ZnTCPP dots and TCPP-based metal organic framework (pMOF) dots have been subtly synthesized for the first time by a universal straightforward exfoliation of bulk porphyrin aggregates or pMOF. These as-designed porphyrin dots perform excellent annihilation ECL activity, also exhibit stable and robust cathodic or anodic NIR ECL properties with different coreactants (potassium peroxydisulfate, hydrogen peroxide or tri-n-propylamine) in aqueous phase. Especially, the ECL efficiency of three kinds of porphyrin dots in S 2 O 8 2− cathodic system are 56, 44, 39-fold higher than that of the Ru(bpy) 3 2+ standard, respectively. As a new type of ECL luminophores, TCPP dots coupled with a lead ion-dependent DNAzyme and hybridization chain reaction cycle amplification are used to fabricate a label free “signal-on” ECL biosensor for ultrasensitive detection of Pb 2+ . A dynamic range from 10 pmol·L −1 to 1 μmol·L −1 with a low limit of detection (1.2 pmol·L −1 ) is obtained. These porphyrin dots provide evidence for the use of organics-based dots as new NIR ECL luminophores for fundamental ECL research, and highlight the significance of small-sized organic nanomaterials in ECL sensing applications.