An ultra-sensitive and ratiometric fluorescent probe based on the DTBET process for Hg2+ detection and imaging applications.

In this article, we present an ultra-sensitive and ratiometric fluorescent probe (TR-Hg) for Hg2+ detection based on the mechanism of aggregation induced emission (AIE) and dark through-bond energy transfer (DTBET). The probe was constructed using tetraphenylethene as the dark donor and rhodamine B thiolactone as the acceptor. By exploiting the advantages of DTBET, which eliminates emission leakage from dark donors and provides nearly 100% energy transfer efficiency, TR-Hg exhibits more than a 30 000-fold fluorescence ratio enhancement after reacting with Hg2+. TR-Hg demostrates (i) a detection limit of 43 pM, which is the lowest among the reported ratiometric Hg2+ probes, (ii) excellent selectivity, fast response-time (<10 s) and a wide pH application range, (iii) strong applicability for paper-based colorimetric assay, where readout can be performed by the naked eye, and (iv) fluorescent imaging of Hg2+ in onion epidermal tissues, indicating its potential use in living organisms.

AND logic gate based fluorescence probe for simultaneous detection of peroxynitrite and hypochlorous acid.

Hypochlorous acid (HOCl) and peroxynitrite (ONOO-) are two of the most important reactive species and associated with various diseases in various physiological and pathological processes. Nonetheless, many of their roles are still vague due to the shortage of methods for simultaneously detecting HOCl and ONOO-. Herein, three simple yet useful fluorogenic probes, LG-1, LG-2 and LG-3, have been fabricated with facile synthesis route and used to monitor the coexistence of HOCl and ONOO- as AND-based logic gate fluorescent probe firstly. LG-1 and LG-2, which consists of 1,3-oxathiolane group and boronate group respectively, were designed to verify the capacity of monitoring HOCl and ONOO- without interference from each other. The result showed that these two groups are perfect reaction sites of detecting HOCl and ONOO- respectively via specific analyte-induced reactions. Hence, LG-3, which is attached by these two groups to suppress the fluorophore core, can response to HOCl and ONOO- simultaneously without mutual interference and generate the significant time-dependent fluorescence enhancement. By investigating the absorption and fluorescence properties of LG-3 towards HOCl and ONOO- individually and collectively, the result confirmed clearly that LG-3 has the capacity of monitoring the coexistence of HOCl and ONOO-, which could act as a two-input AND-based logic gate fluorescent probe.

An ultra-sensitive ratiometric fluorescent probe for hypochlorous acid detection by the synergistic effect of AIE and TBET and its application of detecting exogenous/endogenous HOCl in living cells.

An ultra-sensitive and ratiometric fluorescent probe for hypochlorous acid (HOCl) detection based on the mechanism of aggregation induced emission (AIE) and through-bond energy transfer (TBET) has been reported herein. By exploiting the advantages of AIE and TBET, which eliminates emission leakage from dark donors, the probe exhibits ultra-high sensitivity towards HOCl by an enhancement of over 7000-fold in the fluorescence ratio (I589 nm/I477 nm), which is one of the highest recorded so far. The reaction mechanism has been discussed in detail, and the effects of interferents and the reaction kinetics have also been investigated. Lastly, the successful result of exogenous/endogenous HOCl imaging detection in different cell lines indicates the potential use of the probe in living systems.

Ultra-sensitive fluorescent probes for hypochlorite acid detection and exogenous/endogenous imaging of living cells.

Two fluorescent probes (Naph-1 and Naph-2), which can be prepared via a facile process, have been developed to detect hypochlorite acid (HOCl). The N,N-dimethyl thiocarbamate group quenches the fluorescence of the probes through intramolecular charge transfer (ICT). Upon reaction with HOCl in aqueous buffer, Naph-1 shows ultra-high sensitivity towards HOCl through a 4600-fold increase in fluorescence intensity, as well as a detection limit of 2.37 nM. The probes have been applied to confocal fluorescence imaging of exogenous and endogenous HOCl in living cells.