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In most biophysiological processes, sulfur dioxide (SO 2 ) is an important intracellular signaling molecule that plays an important role. The change of SO 2 in cells are closely related to various diseases such as neurological disorders and lung cancer, so it is necessary to develop fluorescent probes with the ability to accurately detect SO 2 during physiological processes. In this work, we designed and synthesized a multifunctional fluorescent probe TIS. TIS has excellent properties such as near-infrared emission, large stokes shift, excellent SO 2 detection capabilities, low detection limit, high specificity and visualization of color change before and after reaction. Simultaneously, TIS has low cytotoxicity, good biocompatibility, clear cell imaging capability and mitochondrial targeting ability. In addition, the ability of TIS to be applied to different material surfaces for latent fingerprint fluorescence imaging was also explored. TIS provides an excellent method for the accurate detection of SO 2 derivatives and shows great potential applications in near-infrared cellular imaging and latent fingerprint fluorescence imaging., Competing Interests: Declaration of competing interest No conflict of interest exits in the submission of this manuscript, and manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described is original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed. We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work. There is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2023 Elsevier B.V. All rights reserved.)

High-fidelity imaging and long-term visualization of lysosomes are pivotal factors in the functional assessment of lysosomes, which perform an instrumental role in the physiological activity of cells. However, commercial probes have great limitations in lysosome exploration resulting from the aggregation-caused quenching effect as well as photobleaching instability and small Stokes shift. Therefore, we constructed a novel probe named TTAM with triphenylamine as the matrix and morpholine ring as the targeting group. In contrast with commonly accessible Lyso-tracker Red, TTAM has the merits of aggregation-induced emission effect, extremely high quantum yields (51.57 % solid-state) as well as fluorescence intensity, significant photostability, and high resolution. These properties make it ideal for imaging and activity monitoring lysosomes, which provides a powerful condition for bio-imaging., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Hydrogen sulfide and cysteine are momentous endogenous regulators of many physiological processes and maintain a dynamic balance of redox in living organisms. To investigate the inter-relationship of them in vivo, there is a pressing need to develop analytical molecular tools to identify related biomolecules. We construct a mitochondria-targeted single fluorescence probe (Mit-CM) for separately and continuously visualizing H 2 S, Cys and H 2 S/Cys with multi-response fluorescence signals. Mit-CM has the following advantages: (Ⅰ) colorimetric and ratiometric: two well-separated emission bands can ensure accurate detection of the analyte and significant color changes contribute to rapid identification of the analyte by the naked eye; (Ⅱ) mitochondrial localization: study the physiological functions of H 2 S and Cys in mitochondria; (Ⅲ) separate and continuous detection of H 2 S and Cys: reveal the inter-relationship and interconversion of them in biological system. Moreover, the desirable attributes of low cytotoxicity, better biocompatibility and excellent mitochondria enrichment ability indicate that Mit-CM can be employed to achieve detection and observe distribution of H 2 S, Cys and H 2 S/Cys in living organism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Cysteine (Cys), an important organic small molecule containing sulfhydryl groups, plays paramount functions in human pathologies and physiologies. The detection of Cys in living vivo is essential for studying its roles. Here, we designed and synthesized a novel red-emission fluorescent probe AXPI-Cys with highly sensitivity (LOD = 48.9 ± 0.23 nM), rapidly response (<7 min) and colorimetric for detection cysteine. More importantly, the AXPI-Cys was determined Cys in real cystinuria urine samples for the first time with the satisfactory results (92%-99.96%) and employed for specifically location of endogenous/exogenous Cys in living cancer/normal cells and almost non-toxic, that is very valuable for diagnosis of cystinuria and observation of the distribution of Cys in normal cells. Notably, the AXPI-Cys was applied to imaging Cys in BALB/c nude mice with good biocompatibility and desirable tissue-penetration depth. Owing to the superior capability of AXPI-Cys, it provided a desired method to detect Cys in urine samples and cells, and exhibited munificent potential usage in biosystems and imaging studies in vivo., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Real-time monitoring of the cytochrome P450 1A1 (CYP1A1) activity in complex biological systems via a practical tool is highly sought after because of its significant role in the metabolism and bioactivation of various xenobiotics. Herein, according to slight differences in the 3D structure and substrate preference between CYP1A1 and its homologous CYP1A2, a series of novel ratiometric fluorescent probes were designed and synthesized using 1,8-naphthalimide because of its trait of naked-eye visualization and ratiometric fluorescence to achieve the detection of CYP1A1 in biological samples. Among these probes, NEiPN showed good water solubility, highly isoform selectivity and great sensitivity (LOD = 0.04874 nM) for CYP1A1 under simulated physiological conditions, which makes it favorable for monitoring CYP1A1 in vivo. Remarkably, NEiPN exhibited excellent reproducibility when it was used to detect the CYP1A1 content in human liver microsomes, which indicated that it has a great potential for quantifying the CYP1A1 content in real biological samples. Furthermore, NEiPN showed relatively low cytotoxicity and has been successfully applied in biological imaging in living cells and zebrafish. These findings indicate that NEiPN is capable of real-time monitoring of the activity of endogenous CYP1A1, which could provide support for CYP1A1-associated pathological processes.

Cysteine(Cys) is tightly related to physiological and pathological of human, and the imbalance of concentration of cysteine in the intracellular are associated with many diseases. Here, a novel NIR fluorescent probe TCF-Cys was designed and synthesized, and both the optimal excitation and emission wavelength of them were between 650 and 900 nm, that within the "optical window" of biological tissues. In aqueous solution, TCF-Cys, which with an acrylate extremity as a recognizing unit, exhibited excellent "turn-on" fluorescence response for Cys superior to other amino acids and thiols with a limit of detection of 0.1323 μM. Moreover, as an excellent naked-eye colorimetric indicator, TCF-Cys could effectively distinguishing the Cys, Hcy and GSH in aqueous solution through color change. Then, the response mechanism of TCF-Cys for Cys was revealed by TLC, 1 H NMR, HPLC, HRMS and DFT calculation. Finally, TCF-Cys was successfully employed to fluorescence specifically map of exogenous and endogenous Cys in living cells and zebrafish with low toxicity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Fast, highly selective and sensitive thiophenol probes are highly desirable in the field of bioimaging and environmental monitoring. For that, based on the mechanism that thiophenol can effectively cleave the sulfonamide bond selectively, we herein report a dicyanoisophorone-based Red-emitting/NIR probe for thiophenol detection. This probe had some desirable properties such as rapid response, high selectivity and sensitivity, remarkable large Stokes shift (181 nm), Red-emitting/NIR fluorescence region and low LOD value (80 nM, according to 3σ/s). Moreover, this novel Red-emitting/NIR probe can potentially be applied to the detection of thiophenols in real water samples quantitatively and fluorescent imaging in living cells and zebrafishes., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this work, a simple and ultrasensitive localized surface plasmon resonance (LSPR) method that use Au nanoflowers (AuNFs) as a probe was designed for in situ monitoring of alkaline phosphatase (ALP) activity. The AuNFs were fabricated by hydrogen tetrechloroaurate-induced oxidative disruption of polydopamine-coated Au nanoparticles (AuNPs), and subsequently, growth of Au nanopetals on AuNPs occurred. The as-prepared AuNFs showed a much higher LSPR capability and stronger scattering color change than AuNPs. The strategy for in situ cellular ALP activity detection relied on the deposition of Ag on the AuNFs surface, which changed the morphology of AuNFs and led to a tremendous LSPR response and scattering color change. The deposition of Ag shell on AuNFs was related to ALP activity, where ALP catalyzed the hydrolysis of l-ascorbic acid 2-phosphate sesquimagnesium salt hydrate to form l-ascorbic acid (AA), and then AA reduced Ag + to Ag and deposited onto AuNFs. With this concept, the ALP activity could be monitored with a detection limit of 0.03 μU L -1 . Meanwhile, the ALP activity of single HepG2 cells and HEK 293 cells was tracked with a proposed approach, which indicated the trace expression level of ALP in HEK 293T cell and overexpressed level of ALP in HepG2 cells. After treatment with drugs, the cellular ALP activity of HepG2 cells was decreased with the treating time and dose increasing. Therefore, the proposed strategy could be used for tracking the cellular ALP activity, which paved a new avenue for cell studies and held great potential for discovering novel ALP-based drugs applications.

A near-infrared (NIR) and colorimetric fluorescent probe system was developed for Carbon Monoxide (CO) via a Pd 0 -mediated Tsuji-Trost reaction. In this probe, phenoxide anion formation (DPCO - ) was acted as the signal unit and an allyl carbonate group was used as the recognition unit. This non-fluorescent probe molecule can release the relevant fluorophore after conversion of Pd 2+ to Pd 0 by CO. The probe system including probe 1 and Pd 2+ can be used for "naked-eye" detection of CO, and exhibited high selectivity to CO over various other sensing objects. More importantly, the probe system has great potential for fluorescence imaging of intracellular CO in living cells., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Cytochrome P450s have brought considerable attention to researchers for their significant correlations with metabolic behaviors of procarcinogenic chemicals. To better understand the roles of CYP1A in biological and physiological systems, we developed a novel ratiometric fluorescence probe N-((2-hydroxyl ethoxy) ethyl)- 4-methoxy-1, 8-naphthalimide (NEMN) allowing for selectively and sensitively monitoring the target enzymes under physiological conditions and living cells. The probe was designed based on substrate predilection of CYP1A and its outstanding O-dealkylation capacity, and 1, 8-naphthalimide was chosen as fluorophore on account of its desirable photophysical properties. Absorption and emission spectra of the probe solution and reacted metabolism showed obvious red-shift with remarkable colour changes, which indicated that NEMN could be a promising ratiometric detector of CYP1A. Additionally, the selectivity assays displayed that NEMN only sensitive to CYP1A1 and CYP1A2 enzymes with scarce interference of other CYPs. Furthermore, the excellent linear relationships between the ratio of fluorescent intensities and incubation time and enzymes concentration signified time- and concentration- dependence of the probe, which were of desire benefit to quantify and monitor the CYP1A-involved biological behaviors in physiological conditions. The assay in real living samples (Human liver microsomes) further proved the analytical utility of the probe. Finally, the cytotoxicity assay and confocal fluorescence imaging demonstrated that this probe was of great promise for detecting the activity of endogenous CYP1A in human living cells., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A novel label-free fluorescent chemodosimeter (C1) was synthesized, based on coumarin and N-(4-aminobenzoyl)-β-alanine, for the selective detection of cysteine (Cys) over glutathione (GSH), which involved a click reaction of Cys to CN of a Schiff base. The probe C1 featured a fast response (about 3 min), emission in the visible region, and high selectivity. Addition of Cys in HEPES-NaOH solution (pH 7.4) to C1 in water resulted in the appearance of a new emission peak at 445 nm, in company with remarkable enhancement of fluorescence intensity, while other amino acids did not induce any significant fluorescence change. Meanwhile, the addition reaction of Cys to C1 elicited 90.8-fold fluorescence intensity enhancement, which resulted in a change of emission color from orange to blue., (Copyright © 2016 Elsevier Inc. All rights reserved.)

A selective Hg²⁺/Cu²⁺-induced OFF-ON-OFF type of signaling pattern was calculated by density functional theory and time-dependent density functional theory method. Geometries, molecular orbitals, and interaction thermal energies were evaluated at the restricted hybrid Becke's three-parameter exchange functional using 6-31+G(d) basis set and relativistic effective core potentials. The optimized geometric structures are used to perform natural bond orbital (NBO) analysis. The main type of driving force is the electrostatic interactions between the metal ions and the electron-donating oxygen and nitrogen atoms. Maximum absorption spectrums of the complexes are mainly contributed by the HOMO → LOMO transition. The high selectivity of ligand H₂NB for Hg²⁺ results in a "turn-on" fluorescent phenomenon.

Organic AIE nanostructures are extremely important fluorescent dyes for imaging-guided photosensitizing therapy, which are capable of imaging organelles and producing ROS well, however, it remains difficulties nowadays. Here we disclose the development and assembly of a NIR AIE nanoparticle (MeTTSN) by multiple assembling chemical engineering for utilization in cellular LDs, with accurate dynamic monitoring (Pearson's coefficient of 0.981) and suitable particle size distribution (267.04 nm) in PBS solution, effective Stokes shifts (91 nm), valuable quantum yield (5.88%) in water and high bioactivity and stability, superior self-assembly and incredibly 1O 2 and ROS generation. Moreover, under white light irradiation, the MeTTSN , as an ideal PS, displayed superior photosensitivity for active HepG2 cells. Furthermore, the end up living cells' co-staining imaging and flow cytometry revealed that MeTTSN could actively suppress cell growth and cause or lead to cell death. Overall, the current study presents a feasible method for LDs targeting chemical bioengineering and highlights the importance of organic AIE materials PSs medication throughout the healthcare and fluorescent imaging-guided PDT area. • MeTTSN was applied to glow brightly and high-fidelity monitoring lipids droplets. • MeTTSN has suitable particle size distribution in PBS. • MeTTSN has excellent bioactivity and photostability. • MeTTS N has been utilized effectively for the photodynamic etching of cancer cells. [ABSTRACT FROM AUTHOR]