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[Display omitted] • Probe is capable of detecting ONOO− with a longwave fluorescence emission. • TL could monitor high concentration of dexamethasone-induced an up-regulation of ONOO−. • Probe has mitochondrial targeting capability. • Probe have good selectivity and low detection limit. • The imaging demonstrated its value of practical application. Peroxynitrite (ONOO−), as a strong oxidizing reactive nitrogen substance (RNS), is generated endogenously by cells. Its visualization research is crucial to understand relevant disease processes. Herein, we reported a long-wavelength mitochondria-targeted fluorescence "turn on" probe TL. The probe TL could react with ONOO− by using 4-(Bromomethyl)benzeneboronic as a reactive site, which exhibited outstanding characteristics for detection of ONOO−, thus improving response time (about 50 s), sensitivity (DL, 10.1 nM), and emission wavelength (667 nm). Besides, TL displayed well mitochondria targeting and biological visualizing of exogenous and endogenous ONOO− in biological systems. Finally, TL was used to monitor high concentration of dexamethasone-induced an up-regulation of ONOO−. This indicated that TL has excellent potential to study the fluctuation of ONOO− in the physiological and pathological system. [ABSTRACT FROM AUTHOR]

Peroxynitrite (ONOO-), an endogenous reactive oxygen species (ROS), can cause a variety of diseases in organisms at high levels. Golgi oxidative stress produces a large number of ROS, and the quantitative detection of various ROS is of great significance to study Golgi oxidative stress. Therefore, accurate detection of ONOO- level in Golgi is important to reveal the mechanism of ONOO- in living organisms. Here, we developed a Golgi-targeted aggregation-induced emission (AIE) fluorescent probe Gol-ONOO - to detect ONOO- in cells. The probe Gol-ONOO - has the advantages of instant response to ONOO-, high selectivity, low detection limit (250 nM) and large Stoke's shift (180 nm). Most importantly, the probe Gol-ONOO - monitored the increase of ONOO- level caused by monensin-induced oxidative stress in the Golgi apparatus, and it was the first time to realize ONOO- imaging in the Golgi apparatus. • A AIE fluorescent probe Gol-ONOO - was synthesized for detecting peroxynitrite with large Stock's shift. • For the first time, real-time imaging of the ONOO- level of the Golgi apparatus has been achieved. • Gol-ONOO - has been used to monitor the ONOO- level caused by monensin-induced oxidative stress in Golgi for the first time. [ABSTRACT FROM AUTHOR]

Mercury and sulfur dioxide (SO 2) are common pollutants in the ecological environment, which are important factors causing many diseases of organisms. The lack of appropriate analytical tools has limited the further understanding of the relationship between ionic mercury (Hg2+) and SO 2. Herein, a bifunctional fluorescent probe LJ was designed and explored to simultaneously detect Hg2+ and SO 2 via desulfurization reaction and Michael addition reaction, respectively. Probe LJ showed distinct fluorescence responses which a large near-infrared fluorescence enhancement towards Hg2+ at λ em = 713 nm and a blue shift at λ em = 450 nm towards SO 2 without any spectral cross interferences. To the best of our knowledge, this is the first fluorescent probe with dual fluorescent emission channels to detect Hg2+ and SO 2 with the detection limit of 187 nM and 354 nM, respectively. Moreover, cell fluorescent imaging experiments indicated that the probe was mitochondria targetable and provided evidence that SO 2 could be used as an antidote to attenuate the toxicity of Hg2+ in living cells. [Display omitted] • The first fluorescent probe LJ which can detect Hg2+ and SO 2 simultaneously was constructed. • LJ is mitochondria targetable, and can image Hg2+ and HSO 3 − in living cells. • The study presented the first evidence that HSO 3 − could be used as an antidote for Hg2+-induced toxicity in living cells. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is considered as a serious carcinogenic mycotoxin that was widely detected in grains and foods, and its sensitive analysis is of key importance to avoid the health threats for consumers. In this study, a dual-signal aptasensor based on cascade of entropy-driven strand displacement reaction (ESDR) and linear rolling circle amplification (LRCA) was fabricated for ultrasensitive determination of AFB1. At the sensing system, the complementary strand would be released after the aptamer combined with AFB1, which will bring about the functional domains exposed, triggering the subsequent ESDR. Meanwhile, the two strands that were outputted by ESDR would incur the downstream LRCA reaction to produce a pair of long strands to assist in the generation of fluorescence and absorbance signals. Under the optimized conditions, the proposed aptasensor could achieve excellent sensitivity (limit of detection, 0.427 pg/mL) with satisfactory accuracy (recoveries, 92.8–107.9 %; RSD, 2.4–5.0 %), mainly ascribed to the cascade amplification. Importantly, owing to the flexibility design of nucleic acid primer, this analytical method can be applied in monitoring various hazardous substances according to the specific requirements. Our strategy provides some novel insights at signal amplification for rapid detection of AFB1 and other targets. [ABSTRACT FROM AUTHOR]

The rational development of efficient nanozymes for the colorimetric detection of targets is still challenging. Herein, Prussian blue analogues of Ni–Co–MoS 2 nano boxes were fabricated for colorimetric detection of glyphosate and copper ions owing to its peroxidase like activity. At the sensing system, the Ni–Co–MoS 2 nano boxes display high peroxidase activity, which could catalytically oxidize the colourless TMB to blue colour oxTMB. In presence of glyphosate in this sensing system the blue colour is diminished, ascribed to the inhibit the catalytic activity of Ni–Co–MoS 2 nano boxes. Concurrently, the addition of copper ion, which result in blue colour was reappear due to the generation of glyphosate-copper complex formation. The Ni–Co–MoS 2 nano boxes based colorimetric sensing platform was developed to sensitive detection of glyphosate and copper ions with low detection limit of 3 nM for glyphosate and 3.8 nM for copper. This method also displays satisfactory outcomes from real samples analysis and its good accuracy. Therefore, this work provides a great potential for rapid detection of the targets from the environments. [Display omitted] • Ni–Co–MoS 2 nano boxes exhibited superior peroxidase-like activity. • The excellent detection limits of GLY and copper were founded. • This colorimetric sensor displayed potential application in real samples. [ABSTRACT FROM AUTHOR]

It is a challenging and meaningful task to design an enzyme electrochemical biosensor that can maintain high sensitivity while improving stability. In this study, we constructed an enzyme electrochemical biosensor by preparing nanocomposites with multi-stable interface structures. Specifically, the nanocomposite (PGOx@MXene/CS) was prepared by efficient electrostatic assembly of GOx polynanogel (PGOx) onto MXene nanosheets. PGOx could enhance enzyme stability, while the extensive the large specific surface area of MXene could realize the efficient loading of nanocapsules (PGOx) and catalyze the decomposition of toxic intermediate H 2 O 2 , thereby reducing its influence on the stability of enzyme. The linear range of the constructed glucose sensor was 0.03–16.5 mM, the sensitivity was 48.98 μA mM−1·cm−2, and the detection limit was 3.1 μM. After 200 cycles, the current still remained at 85.83% of the initial current value. The high sensitivity, excellent selectivity and great reproducibility verified the effectiveness of the system we constructed. The multi-stable enzyme electrochemical biosensor had a wide application prospect in stable and continuous blood glucose detection. [ABSTRACT FROM AUTHOR]

A fast and accurate method for ultrasensitive monitoring of substrate is significant for cascade molecular detection. Here, we synthesize a glucose oxidase (GOx) microgel with iron coordination (Fe/GOx microgel). The microgel is cross-linked by chitosan and iron ion coordination which construct a tubular structure. Powder X-ray diffraction and Brunauer-Emmett-Teller results confirm the tubular crystal structure with a high specific surface area is formed in the microgel. The tubular structure offers a stable channel for intermediate transport which ensures the stabilization for the intermediate transport, and high specific surface area enhances the interaction between substrates and catalysts. As a result, the sensitivity of the Fe/GOx microgel is 175.5 μA mM−1 cm−2 and the lowest detection limit is 4.42 μM. In addition, the nanoscale Fe/GOx microgel also has the characteristics of reusability and maintains its activity after five times of catalysis. The generation of free radicals during the catalytic process can be detected by light detection and electrochemical signal detection within different detection limits. Therefore, Fe/GOx microgel provides a new platform and catalyst for the precise detection of cascade catalysis. [ABSTRACT FROM AUTHOR]