Synergism of Photo-Induced Electron Transfer and Aggregation-Induced Quenching Mechanisms for Highly Sensitive Detection of Silver Ion and Captopril

Abstract

Carbon-based nanoprobes, with excellent physicochemical performance and biocompatibility, are a kind of ideal nanomaterial for biosensing. Herein, we designed and prepared novel oxygen-doped nitrogen-enrichment carbon nanoribbons (ONCNs) with an excellent optical performance and uniform morphology, which could be used as a dual-mode fluorescence probe for the detection of Ag+ ion and captopril (Ctl) based on the synergism of photo-induced electron transfer and aggregation-induced quenching mechanisms. By recording the changes in fluorescent intensities of ONCNs, the Ag+ ion and Ctl concentrations can be easily tested in real samples. The results displayed that two good linear relationships existed between the change in fluorescent intensity of ONCNs and the concentrations of Ag+ ion and Ctl in the ranges of 3 μM to 30 μM and 1 μM to 30 μM, with the detection limit of 0.78 µM and 74 nM, respectively. The proposed sensing platform has also been successfully applied for the Ctl analysis in commercial tablet samples based on its high selectivity, proving its value in practical applications.

Turn-on detection of Al3+ ions using quinoline-based tripodal probe: mechanistic investigation and live cell imaging applications

“…Initially, TQSB was almost non-fluorescent due to the related CN isomerization process in its excited state 63,64 together with the photoinduced electron transfer (PeT) arising from the N atom of the imine group (donor) to the excited-state fluorophore (acceptor). 65–72 Three imine-N atoms along with three quinoline-N atoms act as hard donor sites to preferentially bind with hard Al 3+ ions. Such a strong binding results in restricted CN– isomerization, and subsequently N6 binding to Al 3+ blocks the PET process – both the effects combinedly become conducive to enhanced fluorescence of TQSB in complex TQSB –Al 3+ .…”