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Pb2+ is a heavy metal ion pollutant that poses a serious threat to human health and ecosystems. The conventional methods for detecting Pb2+ have several limitations. In this study, we introduce a novel fluorescent probe that enables the detection of Pb2+ in the near-infrared region, free from interference from other common ions. A unique characteristic of this probe is its ability to rapidly and accurately identify Pb2+ through ratiometric measurements accompanied by a large Stokes shift of 201 nm. The limit of detection achieved by probe was remarkably low, surpassing the standards set by the World Health Organization, and outperforming previously reported probes. To the best of our knowledge, this is the first organic small-molecule fluorescent probe with both near-infrared emission and ratiometric properties for the detection of Pb2+. We present a triple-mode sensing platform constructed using a probe that allows for the sensitive and selective recognition of Pb2+ in common food items. Furthermore, we successfully conducted high-quality fluorescence imaging of Pb2+ in various samples from common edible plants, HeLa cells, Caenorhabditis elegans , and mice. Importantly, the probe-Pb2+ complex exhibited tumour-targeting capabilities. Overall, this study presents a novel approach for the development of fluorescent probes for Pb2+ detection. [Display omitted] • This study develops a novel probe for ratiometric and NIR detection of Pb2+ for the first time. • A fluorescence/colorimetric/smartphone sensing platform for Pb2+ detection was fabricated. • The triple-mode sensing platform was successfully applied to the analysis of Pb2+ in various foods. • The probe was successfully applied to bioimaging and has tumour-targeting capabilities. [ABSTRACT FROM AUTHOR]

It's important to pay great attention to the detection of CN− due to its high toxicity. Based on ESIPT characteristics, we design, synthesize and characterize the colorimetric and fluorescence "turn-on" probe AHAM to recognize CN−, which has the large Stokes shift (228 nm), exhibits high sensitivity and excellent selectivity. The limit detection of the probe AHAM for CN− was 1.94 × 10−8 M, which was much lower than the standard set by WHO and many previously reported probes. The recognition mechanism between AHAM and CN− was investigated by spectroscopic analysis, 1H NMR titration and mass spectrometry. To our surprise, AHAM could not only identify CN− reversibly, but also recognize CN− accurately in test paper and silica gel plate applications. Furthermore, AHAM was successfully used for fluorescence imaging in C. elegans and mice. It provides the new easy, fast and accurate method to detect CN−. [Display omitted] • The Stokes shift of AHAM toward CN− reached 228 nm. • AHAM recognized CN− with low LOD selectively, sensitively and reversibly. • AHAM achieved to visualize CN− in C. elegans and mice. [ABSTRACT FROM AUTHOR]

[Display omitted] • The probe toward CN− with large Stokes shift was firstly reported based on ESIPT-AIE. • The probe showed high selectivity, rapid response and the low limit of detection. • It was detect endogenous CN− in food samples and living system successfully. Cyanide (CN–) is one of the strongest and fastest-acting toxic substances, and its excessive presence will cause great harm to the environment, food and human health. Although several fluorescent probes that recognize CN– have been extensively reported, developing the fluorescent probe with aggregation-induced emission (AIE) and large Stokes shift is still an extremely difficult problem due to lack of effective strategies. Thus, continuing efforts to seek novel, structurally distinct and functionally specific structures with large Stokes shift and AIE features are highly anticipated. Herein, we design and synthesize a novel asymmetric bis-Schiff base block (named as HPBC) based on the excited state intramolecular proton transfer (ESIPT) and AIE mechanism. Benefiting from restriction of intramolecular rotation and –CN electron-withdraw nature promoting the ESIPT effect of HPBC in the recognition system, HPBC shows large Stokes shift (243 nm), high selectivity, rapid identification of CN– and AIE effects. Excitingly, the limit of detection (LOD) was calculated to be 1.32 × 10-7 M, which was much lower than the 1.9 × 10-6 M specified by the World Health Organization and better than other previously reported probes. More importantly, further investigations demonstrated that the molecule we designed was successfully applied to sense endogenous CN– in food samples and the low cytotoxicity of HPBC was allowed to discover CN– in C. elegans , mice and HeLa cells. Overall, this work provides a new viewpoint of the rational design and synthesis of fluorescent probe toward CN– with AIE and large Stokes shift features, and triggers the discovery of new functions and properties of biological materials, which would open a new frontier for probes. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO), a significant gas transmitter, plays a vital role in the intricate functioning of living systems and is intimately linked to a variety of physiological and pathological processes. To comprehensively investigate CO within biological system, researchers have widely adopted CORM-3, a compound capable of releasing CO, which serves as a surrogate for CO. It aids in elucidating the physiological and pathological effects of CO within living organisms and can be employed as a therapeutic drug molecule. Therefore, the pivotal role of CORM-3 necessitates the development of effective probes that can facilitate the visualization and tracking of CORM-3 in living systems. However, creating fluorescent probes for real-time imaging of CORM-3 in living species has proven to be a persisting challenge that arises from factors such as background interference, light scattering and photoactivation. Herein, the BNDN fluorescent probe, a brand-new near-infrared is proposed. Remarkably, the BNDN probe offers several noteworthy advantages, including a substantial Stokes shift (201 nm), heightened sensitivity, exceptional selectivity, and an exceedingly low CORM-3 detection limit (0.7 ppb). Furthermore, the underlying sensing mechanism has been meticulously examined, revealing a process that revives the fluorophore by reducing the complex Cu2+ to Cu+. This distinctive NIR fluorescence "turn-on" character, coupled with its larger Stokes shift, holds great promise for achieving high resolution imaging. Most impressively, this innovative probe has demonstrated its efficacy in detecting exogenous CORM-3 in living animal. It is important to underscore that these endeavors mark a rare instance of a near-infrared probes successfully detecting exogenous CORM-3 in vivo. These exceptional outcomes highlighted the potential of BNDN as a highly promising new tool for in vivo detection of CORM-3. Considering the impressive imaging capabilities demonstrated by BNDN presented in this study, we anticipate that this tool may offer a compelling avenue for shedding light on the roles of CO in future research endeavors. A novel NIR fluorescent probe BNDN for detection of CORM-3 in living cells and animalA novel robust NIR fluorescent probe for the detection of CORM-3 has been reported. The probe not only demonstrates remarkable selectivity towards CORM-3 over other potential interfering species, but it also exhibits high sensitivity to CORM-3, yielding 20-fold fluorescence enhancement. Particularly, the probe effectively tracks and images CORM-3 in vivo such as mice. These findings suggest that BNDN holds significant promise as a tool for exploring CO-related physiological and pathological processes in living systems. [Display omitted] • Reporting a novel probe for simultaneously detecting CORM-3 in living cells and animals. • This probe shows enhanced fluorescence in the NIR region with a large Stokes shift. • The underlying sensing mechanism has been meticulously examined. [ABSTRACT FROM AUTHOR]