Ratiometric Fluorescent Probe for Super-Resolution Imaging of Lysosome HClO in Ferroptosis Cells.

Ferroptosis is an iron-dependent programmed cell death that is characterized by the dysregulation of lipid reactive oxygen species (ROS) production, causing abnormal changes in hypochlorous acid (HClO) levels in lysosomes. Super-resolution imaging can observe the fine structure of the lysosome at the nanometer level; therefore, it can be used to detect lysosome HClO levels during ferroptosis at the suborganelle level. Herein, we utilize a ratiometric fluorescent probe, SRF-HClO, for super-resolution imaging of lysosome HClO. Structured-illumination microscopy (SIM) improves the accuracy of lysosome targeting and enables the probe SRF-HClO to be successfully applied to rapidly monitor the up-regulated lysosome HClO at the nanoscale during inflammation and ferroptosis. Importantly, the probe SRF-HClO can also detect HClO changes in inflammatory and ferroptosis mice and evaluate the inhibitory effect of ferroptosis on mice tumors.

Decontamination Effect of Hypochlorous Acid Dry Mist on Selected Bacteria, Viruses, Spores, and Fungi as Well as on Components of Electronic Systems.

This publication presents the effect of hypochlorous acid dry mist as a disinfectant on selected bacteria, viruses, spores, and fungi as well as on portable Microlife OXY 300 finger pulse oximeters and electronic systems of Raspberry Pi Zero microcomputers. The impact of hypochlorous acid on microbiological agents was assessed at concentrations of 300, 500, and 2000 ppm of HClO according to PN-EN 17272 (Variant I). Studies of the impact of hypochlorous acid fog on electronic components were carried out in an aerosol chamber at concentrations of 500 ppm and 2000 ppm according to two models consisting of 30 (Variant II) and 90 fogging cycles (Variant III). Each cycle included the process of generating a dry mist of hypochlorous acid (25 mL/m3), decontamination of the test elements, as well as cleaning the chamber of the disinfectant agent. The exposure of the materials examined on hypochlorous acid dry mist in all variants resulted in a decrease in the number of viruses, bacteria, spores, and fungi tested. In addition, the research showed that in the variants of hypochlorous acid fogging cycles analyzed, no changes in performance parameters and no penetration of dry fog of hypochlorous acid into the interior of the tested medical devices and electronic systems were observed.

[An in vitro experiment on the stability and irritant of hypochlorous acid in oral cavity].

PURPOSE: To study the stability of physicochemical properties and sterilizing effect about two commercially available hypochlorous acid (HClO) products under simulated clinical conditions, and to evaluate the compatibility of HClO on soft and hard tissues and cells in oral cavity. METHODS: Samples of HClO solution with different production processes were prepared, to detect the changes of physicochemical indexes of each sample over time under simulated clinical conditions (shielded from light at 20-25 ℃, open the cover for 5 minutes every day), including free available chlorine, oxidation-reduction potential and pH. Through suspension quantitative germicidal test, the antibiosis-concentration curve of HClO solution was made, so as to calibrate the change of antibacterial ability of disinfectant with the decrease of available chlorine content during storage. Pulp, tongue and dentine were immersed in PBS, 100 ppm HClO, 200 ppm HClO and 3% NaClO. The influence on soft and hard tissues was evaluated by weighing method and microhardness test. The toxic effects of HClO, NaClO and their 10-fold diluent on human gingival fibroblasts were determined by CCK-8 cytotoxicity assay. GraphPad PRIS 8.0 software was used to analyze the data. RESULTS: Under simulated conditions, the free available chlorine (FAC) of HClO solution decayed with time, and the attenuation degree was less than 20 ppm within 1 month. The bactericidal effect of each HClO sample was still higher than 5log after concentration decay. There was no obvious dissolution and destruction to soft and hard tissues for HClO(P＞0.05). The cell viability of HClO to human gingival fibroblast cells (HGFC) was greater than 80%, which was much higher than 3% NaClO (P＜0.001). CONCLUSIONS: The bactericidal effect and stability of HClO solution can meet clinical needs, which has low cytotoxicity and good histocompatibility. It is expected to become a safe and efficient disinfection product in the field of living pulp preservation and dental pulp regeneration.

A smart hypochlorous acid fluorescent probe enabling Ibuprofen-release for osteoarthritis theranostics.

Background: Osteoarthritis (OA) standing as the most prevalent form of arthritis, closely associates with heightened levels of reactive oxygen species, particularly hypochlorous acid (HOCl). Although there are numerous probes available for detecting HOCl in the OA region, probes with dual functions of diagnostic and therapeutic capabilities are still significantly lacking. While this type of probe can reduce the time gap between diagnosis and treatment, which is clinically needed. Methods: We developed a fluorescent probe (DHU-CBA1) toward HOCl with theranostics functions through the release of methylene blue (MB) and ibuprofen (IBP) in this work. DHU-CBA1 can detect HOCl with high specificity and sensitivity, releasing MB and IBP with an impressive efficiency of ≥ 95% in vitro. Results: DHU-CBA1 exhibits good biosafety, enabling in vivo imaging of endogenous HOCl, along with reducing arthritis scores, improving synovitis and cartilage damage, and maintaining catabolic balance while alleviating senescence in cartilage. Conclusions: This study proposes a novel approach to enhance osteoarthritis therapy by releasing IBP via a smart HOCl-enabled fluorescent probe.

Highly purified hypochlorous acid water facilitates glucose metabolism and memory formation in type 2 diabetic mice associated with altered-gut microbiota.

Hypochlorous acid (HOCl) is an endogenous oxidant and chlorinating agent in mammals that is effective against a broad range of microorganisms. However, the effects of exogenous HOCl on biological processes have not been reported. In this study, the effects of highly purified slightly acidic hypochlorous acid water (HP-HAW) were investigated. After the safety of oral administration of HP-HAW was confirmed, the effects of HP-HAW on glucose homeostasis were assessed in mice. HP-HAW treatment significantly improved blood glucose levels in hyperglycemic condition. Based on the 16S rRNA sequencing, HP-HAW treatment significantly increased the diversity and changed the composition of gut microbiota by decreasing the abundance of genus Romboutsia in mice fed normal chow. In obese mice, HP-HAW administration tended to improve glucose tolerance. HP-HAW also attenuated memory impairments and changes N-methyl-d-aspartate (NMDA) receptor mRNA expression in obese mice. HP-HAW treatment suppressed Il-6 mRNA expression in the hippocampus in type 2 diabetic mice. Overall, these results support HP-HAW as a potential therapeutic agent to improve or prevent glucose tolerance and memory decline via gut microbiota alteration.

A Mitochondria-Targeting Fluorescent Probe for the Dual Sensing of Hypochlorite and Viscosity without Signal Crosstalk in Living Cells and Zebrafish.

Hypochlorite (ClO-) and viscosity both affect the physiological state of mitochondria, and their abnormal levels are closely related to many common diseases. Therefore, it is vitally important to develop mitochondria-targeting fluorescent probes for the dual sensing of ClO- and viscosity. Herein, we have explored a new fluorescent probe, XTAP-Bn, which responds sensitively to ClO- and viscosity with off-on fluorescence changes at 558 and 765 nm, respectively. Because the emission wavelength gap is more than 200 nm, XTAP-Bn can effectively eliminate the signal crosstalk during the simultaneous detection of ClO- and viscosity. In addition, XTAP-Bn has several advantages, including high selectivity, rapid response, good water solubility, low cytotoxicity, and excellent mitochondrial-targeting ability. More importantly, probe XTAP-Bn is successfully employed to monitor the dynamic change in ClO- and viscosity levels in the mitochondria of living cells and zebrafish. This study not only provides a reliable tool for identifying mitochondrial dysfunction but also offers a potential approach for the early diagnosis of mitochondrial-related diseases.

Rapid-response near-infrared fluorescence probe for colorimetric detection of HClO and its applications in environmental monitoring and biological imaging.

As a crucial endogenous reactive oxygen species, hypochlorous acid (HClO) plays an indispensable role in numerous physiological and pathological processes. Additionally, it serves as a biomarker closely associated with inflammation and liver injury. The utilization of near-infrared fluorescence probes has surged in recent years for live biological imaging, owing to their minimal tissue damage and potent tissue penetration capabilities. In this work, a novel near-infrared fluorescence probe MB-HPD was synthesized to sensitively detect HClO. Probe MB-HPD exhibits remarkable selectivity, high sensitivity (14.3 nM), and rapid response towards HClO (20 s). Probe MB-HPD has demonstrated successful application in the imaging of HClO within cells and zebrafish. Remarkably, it has proven to be effective for detecting HClO within environmental samples, as well as imaging HClO in mice models of arthritis and APAP-induced liver injury. These findings indicate the broad applicability of probe MB-HPD, offering a promising avenue for designing highly selective near-infrared fluorescence probes suitable for real-time HClO monitoring.

An ESIPT + AIE based dual-response fluorescent probe for continuous detection of PhSH and HClO and visualization of PhSH-induced oxidative stress in living cells.

As a valuable industrial chemical, thiophenol (PhSH) is poisonous, which can be easily absorbed by the human body, leading to many serious health issues. In addition, PhSH-triggered oxidative stress is considered to be related with the pathogenesis and toxicity of PhSH. Therefore, efficient methods for monitoring PhSH and ROS production induced by PhSH in living systems are very meaningful and desired. Herein, we reasonably developed a facile dual-response fluorescent probe (HDB-DNP) by incorporating the dinitrophenyl (DNP) group into a novel methylthio-substituted salicylaldehyde azine (HDB) with AIE and ESIPT features. The probe itself was non-fluorescent owing to the strong quenching effect of DNP group. In the presence of PhSH, HDB-DNP gave an intense red fluorescence (610 nm), which can rapidly switch to green fluorescence (510 nm) upon further addition of HClO, allowing the successive detection of PhSH and HClO in two well-separated channels. HDB-DNP proved to be a very promising dual-functional probe for rapid (PhSH: < 17 min; HClO: 10 s) and selective detection of PhSH and HClO in physiological conditions with low detection limit (PhSH: 13.8 nM; HClO: 88.6 nM). Inspired by its excellent recognition properties and low cytotoxicity, HDB-DNP was successfully applied for monitoring PhSH and PhSH-induced HClO generation in living cells with satisfactory results, which may help to better understand the pathogenesis of PhSH-related diseases.

The efficient application of instilling negative pressure wound therapy with a hypochlorous acid-preserved wound cleanser: a case series and practical advice.

BACKGROUND: The use of negative pressure wound therapy with instillation and dwell time (NPWTi-d) has been shown to be effective in removing nonviable tissue, reducing bioburden, and promoting granulation tissue formation in acute and chronic infected wounds. OBJECTIVE: To illustrate the clinical efficacy of the use of pure hypochlorous acid (pHA) antimicrobially preserved wound cleansing solution as the instillation fluid for NPWTi-d (NPWTi-d/pHA) in wound bed preparation in patients with complex wounds. CASE REPORT: The treatment protocol for use of NPWTi-d/pHA in preparing wound beds for final closure is demonstrated in 3 illustrative cases of patients with complex wounds resulting from necrotizing infection and trauma with heavy contamination. All 3 patients developed a healthy-appearing wound bed deemed suitable for primary closure an average of approximately 1 month following initial surgical debridement. CONCLUSION: The cases presented demonstrate the ability of a pHA antimicrobially preserved wound cleansing solution used as the instillation fluid with NPWTi-d to aid in bacterial reduction, mechanical debridement, and promotion of wound healing. Use of NPWTi-d/pHA in these cases of extensive necrotizing infection and posttraumatic injury with heavy contamination allowed for final closure an average of 1 month after initial surgical debridement.

Large stokes shift and near-infrared fluorescent probe for bioimaging and evaluating the HClO in an rheumatoid arthritis mouse model.

It is crucial to identify aberrant HClO levels in living things since they pose a major health risk and are a frequent reactive oxygen species (ROS) in living organisms. In order to detect HClO in various biological systems, we created and synthesized a near-infrared fluorescent probe with an oxime group (-C = N-OH) as a recognition unit. The probe DCMP1 has the advantages of fast response (10 min), near-infrared emission (660 nm), large Stokes shift (170 nm) and high selectivity. This probe DCMP1 not only detects endogenous HClO in living cells, but also enables further fluorescence detection of HClO in living zebrafish. More importantly, it can also be used for fluorescence imaging of HClO in an rheumatoid arthritis mouse model. This fluorescent probe DCMP1 is anticipated to be an effective tool for researching HClO.

IBPA a mutual prodrug of ibuprofen and acetaminophen alleviates inflammation, immune dysregulation and fibrosis in preclinical models of systemic sclerosis.

Systemic sclerosis (SSc) is a devastating autoimmune illness with a wide range of clinical symptoms, including vascular abnormalities, inflammation, and persistent and progressive fibrosis. The disease's complicated pathophysiology makes it difficult to develop effective therapies, necessitating research into novel therapeutic options. Molecular hybridization is a strategy that can be used to develop new drugs that act on two or multiple targets and represents an interesting option to be explored for the treatment of complex diseases. We aimed to evaluate the effects of a hybrid mutual prodrug of ibuprofen and acetaminophen (IBPA) in peripheral blood mononuclear cells (PBMC) isolated from SSc patients, and in an in vivo model of SSc induced in BALB/c mice by intradermal injections of hypochlorous acid (HOCl) for 6 weeks. The mice were treated at the same time with daily intraperitoneal injections of IBPA (40 mg/kg). Pulmonary and skin fibrosis as well as immune responses were evaluated. IBPA significantly decreased the release of cytokines in PBMC culture supernatants from SSc patients after stimulation with phytohemagglutinin-M (IL-2, IL-4, IL-6, IL-10, IL-13, IL-17A, TNF and IFN-γ).In HOCl-induced SSc, IBPA treatment prevented dermal and pulmonary fibrosis, in addition to reducing CD4 + T and B cells activation and reversing the M2 polarization of macrophages in spleen cells, and inhibiting IFN-γ secretion in splenocyte cultures. These results show the anti-inflammatory and antifibrotic effects of IBPA in SSc and highlight the therapeutic potential of this mutual prodrug, providing support for future studies.

Correlation between disinfection efficacy and cumulative amount of free chlorine reaching various positions during ultrasonic fogging with hypochlorite solution.

When a hypochlorite solution is ultrasonically fogged in a room, free chlorine, i.e., HOCl and OCl-, reaches various positions in two forms: fine fog droplets and gaseous hypochlorous acid（HOCl(g)）. In this study, the cumulative amount of free chlorine reaching various positions on the floor away from the fogger was measured in a 90-m3 room, using a sulfamate-carrying glass-fiber filter indicator. The fine droplets were blown out from the fogger into the spaces at different discharge port angles of 30 - 90°. Free chlorine was successfully trapped by sulfamate, forming monochlorosulfamate, which was stably retained on the indicator. The cumulative amount of free chlorine（ ng/indicator） increased with fogging time at each position and depended on the blow angle and distance from the fogger. Minor differences in the HOCl(g) concentration near the floor at all positions were observed. The disinfection efficacy of the fogging treatment against Staphylococcus aureus on wet surfaces was relatively higher at positions near the fogger and lower at positions far from the fogger. At each discharge port angle, a strong correlation between the logarithmic reduction in relative viable cells and the cumulative amount of free chlorine reaching S. aureus plates was observed. The slopes of the regression lines of correlation diagrams as a function of the cumulative amount of free chlorine were between -0.0362 and -0.0413 ng-1. This study demonstrated that the cumulative amount of free chlorine measured using the filter indicator could reflect the sum of the free chlorine of both fine droplets and HOCl(g), and that the disinfection efficiency depended on the cumulative amount of free chlorine reaching different areas.

Evaluation of surface tensions and root-dentin surface contact angles of different endodontic irrigation solutions.

BACKGROUND: Surface tension and contact angle properties, which play a crucial role in determining the effectiveness of irrigation solutions in penetrating dentin surfaces and dentin tubules, are highly important for the development of new irrigation solutions and their preferences. The aim of the current study was to compare the surface tension and contact angle properties of different irrigation solutions used in endodontics, both on the dentin surface and within dentin tubules. METHODS: In this study, the contact angles and surface tensions of 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 5% boric acid (BA), 0.02% hypochlorous acid (HOCl), 0.2% chlorine dioxide (ClO2), Biopure MTAD, QMix solutions, and distilled water (control group) were measured. Measurements were conducted using a goniometer device (Attension Theta Lite Tensiometer, Biolin Scientific, USA), employing the sessile drop method for contact angle measurements on pre-prepared dentin surfaces, and the pendant drop method for surface tension. RESULTS: Contact angle measurements revealed no statistically significant differences between the contact angle values of MTAD, ClO2, and CHX or between NaOCl, QMix, BA, and HOCl (p > 0.05). However, EDTA exhibited a significantly greater contact angle than did MTAD, ClO2, CHX, NaOCl, QMix, BA, and HOCl (p < 0.05). Furthermore, the contact angle of dentin with distilled water was greater than that with all other solutions tested (p < 0.05). Surface tension measurements revealed that the surface tension values of QMix and MTAD were statistically similar (p > 0.05). CHX exhibited lower surface tension than distilled water and HOCl (p < 0.05), and it also had lower surface tension than ClO2, NaOCl, and BA (p < 0.05). Additionally, the surface tension of the samples treated with EDTA was greater than that of all other solutions tested (p < 0.05). CONCLUSION: The direct linear relationship between the surface tension of liquids and contact angles on different surfaces may not always hold true, and these values should be considered independently for each solution on various surfaces. Considering the contact angles and surface tension properties of irrigation solutions with root canal dentin, it can be suggested for clinical use that ClO2 could be recommended over NaOCl, and similarly, BA could be recommended over EDTA.

In-situ evaluation the fluctuation of hypochlorous acid in acute liver injury mice models with a mitochondria-targeted NIR ratiometric fluorescent probe.

Acute liver injury (ALI) is a frequent and devastating liver disease that has been made more prevalent by the excessive use of chemicals, drugs, and alcohol in modern life. Hypochlorous acid (HClO), an important biomarker of oxidative stress originating mainly from the mitochondria, has been shown to be intimately connected to the development and course of ALI. Herein, a novel BODIPY-based NIR ratiometric fluorescent probe Mito-BS was constructed for the specific recognition of mitochondrial HClO. The probe Mito-BS can rapidly respond to HClO within 20 s with a ratiometric fluorescence response (from 680 nm to 645 nm), 24-fold fluorescence intensity ratio enhancement (I645/I680), a wide pH adaptation range (5-9) and the low detection limit (31 nM). The probe Mito-BS has been effectively applied to visualize endogenous and exogenous HClO fluctuations in living zebrafish and cells based on its low cytotoxicity and prominent mitochondria-targeting ability. Furthermore, the fluorescent probe Mito-BS makes it possible to achieve the non-invasive in-situ diagnosis of ALI through in mice, and provides a feasible strategy for early diagnosis and drug therapy of ALI and its complications.

Recent development in dual function fluorescence probes for HOCl and interaction with different bioactive molecules.

Reactive oxygen species (ROS), reactive sulfur species (RSS), metal ions, and nitrogen species (RNS) play important roles in a variety of biological processes, such as a signal transduction, inflammation, and neurodegenerative damage. These species, while essential for certain functions, can also induce stress-related diseases. The interrelation between ROS, RSS, Metal ions and RNS underscores the importance of quantifying their concentrations in live cells, tissues, and organisms. The review emphasizes the use of small-molecule-based fluorescent/chemodosimeter probes to effectively measure and map the species' distribution with high temporal and spatial precision, paying particular attention to in vitro and in vivo environments. These probes are recognized as valuable tools contributing to breakthroughs in modern redox biology. The review specifically addresses the relationship of HOCl/ClO‾ (hypochlorous acid/Hypochlorite) with other reactive species. (Dual sensing probes).

A tumor-targeting two-photon fluorescent probe with a far-red to NIR emission for imaging basal hypochlorite in cancer cells and tumor.

Cancer cells have a high abundance of hypochlorite compared to normal cells, which can be used as the biomarker for imaging cancer cells and tumor. Developing the tumor-targeting fluorescent probe suitable for imaging hypochlorite in vivo is urgently demanded. In this article, based on xanthene dye with a two-photon excited far-red to NIR emission, a tumor-targeting two-photon fluorescent probe (Biotin-HClO) for imaging basal hypochlorite in cancer cells and tumor was developed. For ClO-, Biotin-HClO (20.0 µM) has a linear response range from 15.0 × 10-8 to 1.1 × 10-5 M with a high selectivity and a high sensitivity, a good detection limit of 50 nM and a 550-fold fluorescence enhancement with high signal-to-noise ratio (20 mM PBS buffer solution with 50 % DMF; pH = 7.4; λex = 605 nm; λem = 635 nm). Morover, Biotin-HClO exhibited excellent performance in monitoring exogenous and endogenous ClO- in cells, and has an outstanding tumor-targeting ability. Subsequently, Biotin-HClO has been applied for imaging ClO- in 4T1 tumor tissue to distinguish from normal tissue. Furthermore, Biotin-HClO was successfully employed for high-contrast imaging 4T1 tumor in mouse based on its tumor-targeting ability. All these results proved that Biotin-HClO is a useful analytical tool to detect ClO- and image tumor in vivo.

Evaluation of treatment of methicillin-resistant Staphylococcus aureus biofilms with intermittent electrochemically generated H2O2 or HOCl.

Chronic wound infections can be difficult to treat and may lead to impaired healing and worsened patient outcomes. Novel treatment strategies are needed. This study evaluated the effects of intermittently produced hydrogen peroxide (H2O2) and hypochlorous acid (HOCl), generated via an electrochemical bandage (e-bandage), against methicillin-resistant Staphylococcus aureus biofilms in an agar membrane biofilm model. By changing the working electrode potential, the e-bandage generated either HOCl (1.5 VAg/AgCl) or H2O2 (-0.6 VAg/AgCl). The degree of biocidal activity of intermittent treatment with HOCl and H2O2 correlated with HOCl treatment time; HOCl treatment durations of 0, 1.5, 3, 4.5, and 6 hours (with the rest of the 6-hour total treatment time devoted to H2O2 generation) resulted in mean biofilm reductions of 1.36 ± 0.2, 2.22 ± 0.16, 3.46 ± 0.38, 4.63 ± 0.74, and 7.66 ± 0.5 log CFU/cm2, respectively, vs. non-polarized controls, respectively. However, application of H2O2 immediately after HOCl treatment was detrimental to biofilm removal. For example, 3 hours HOCl treatment followed by 3 hours H2O2 resulted in a 1.90 ± 0.84 log CFU/cm2 lower mean biofilm reduction than 3 hours HOCl treatment followed by 3 hours non-polarization. HOCl generated over 3 hours exhibited biocidal activity for at least 7.5 hours after e-bandage operation ceased; 3 hours of HOCl generation followed by 7.5 hours of non-polarization resulted in a biofilm cell reduction of 7.92 ± 0.12 log CFU/cm2 vs. non-polarized controls. Finally, intermittent treatment with HOCl (i.e., interspersed with periods of e-bandage non-polarization) for various intervals showed similar effects (approximately 6 log CFU/cm2 reduction vs. non-polarized control) to continuous treatment with HOCl for 3 hours, followed by 3 hours of non-polarization. These findings suggest that timing and sequencing of HOCl and H2O2 treatments are crucial for maximizing biofilm control when using an e-bandage strategy.

Assessing the stability and sporicidal efficacy of oxidizing disinfectants.

BACKGROUND: The role of the healthcare environment in the transmission of clinical pathogens is well established. EN 17126:2018 was developed to address the need for regulated sporicidal product testing and includes a realistic medical soil to enable validation of products that claim combined cleaning and disinfection efficacy. AIM: To investigate the chemical stability and sporicidal efficacy of oxidizing disinfectant products in the presence of simulated clean and medical dirty conditions. METHODS: Disinfectant stability and sporicidal efficacy were evaluated in like-for-like ratios of soil:product. Disinfectants were exposed to simulated test soils and free chlorine, chlorine dioxide or peracetic acid concentrations were measured using standard colorimetric methods. Efficacy of disinfectants against C. difficile R027 endospores was assessed as per EN 17126:2018. Comparisons of performance between clean and medical dirty conditions were performed using one-way analysis of variance. Correlation analysis was performed using Pearson product-moment correlation. FINDINGS: Performance of chlorine-releasing agents (sodium dichloroisocyanurate, chlorine dioxide and hypochlorous acid) was concentration dependent, with 1000 ppm chlorine showing reduced stability and efficacy in dirty conditions. By contrast, peracetic acid product demonstrated stability and consistently achieved efficacy in dirty conditions. CONCLUSION: These results have implications for clinical practice, as ineffective environmental decontamination may increase the risk of transmission of pathogens that can cause healthcare-associated infections.

A New Fluorene-Based Fluorescent Probe for Recognition of Hypochlorite Ions and its Applications.

Oxidative stress is a trigger for many diseases and occurs with the unstable hypochlorite (ClO-), known as one of the reactive oxygen species (ROS) in organisms. Then, HOCI is acknowledged as an oxidizing species that eliminates a variety of environmental pollutants. Hence, the development of novel methodologies for the selective and precise identification of HOCl/ ClO- is considered to be of utmost importance. In this study, the design, characterization, and applications of a fluorene-based fluorescent probe (FHBP) dependent on the ESIPT mechanism with a "turn-on" response for the sensitive/selective determination of ClO- against other competing samples were reported. The experimental results indicated that the detection limit for ClO-could be quantitatively determined by the probe to be 8.2 × 10-7 M. The binding constant of the probe FHBP with ClO- was computed as 9.75 × 103 M-1. In addition, the response time of FHBP was appointed to be 30 s, indicating a rapid reaction with ClO-. It has also been demonstrated that this probe can be successfully used for the detection of ClO- on filter papers, TLC sheets, cotton swabs, and real samples.

A new FRET-based fluorescent probe: Colorimetric and ratiometric detection of hypochlorite and anti-counterfeiting applications.

Hypochlorite (ClO-), as the main component of widely used disinfectants in daily life, comes into closer contact with the human body, which can lead to a number of diseases. The high-performance method is increasingly needed to detect ClO- in our daily life. In this report, we successfully synthesized a FRET ratiometric fluorescent probe (NDAC) containing benzoxadiazole moieties and coumarin moieties bound via ethylenediamine. As expected, NDAC has excellent selectivity and anti-interference ability toward ClO-, and the ratio of fluorescence intensity (I471 nm/I533 nm) has a very good linear relationship with the concentration of ClO-, with a wide linear range (2.5-1750 µM) and low detection limit (0.887 µM). Furthermore, we have successfully applied it for the quantitative detection of ClO- in water samples in daily life. At the same time, there is a very clear change in the fluorescence color after the reaction of the NDAC with ClO-. The blue/green value (B/G) of this color change also shows a very good linear relationship to ClO- (5.0-1000 µM). Therefore, the NDAC has also been successfully used for test strip detection and quantitative detection of ClO- in actual samples through smartphone-based fluorescence image analysis, and this method can provide faster, more convenient and more accessible detection. In addition, NDAC sensors also have potential applications in the field of information anti-counterfeiting.