Detection Of Anions Research Articles

Photoelectrochemical detection of superoxide anions released from mitochondria in HepG2 cells based on the synergistic effect of MnO2@Co3O4 core-shell p-n heterojunction

The detection and comparison of the amount of superoxide anion (O2.-) released by different complexes in mitochondrial electron transport chain (ETC) can locate the main electron leakage sites in mitochondria. In order to realize this, we designed an ultrasensitive photoelectrochemical (PEC) sensor by in situ hydrothermal growth of MnO2 nanosheets on Co3O4 nanowires array modified Ti substrate (NWA|Ti). Due to the formation of a core-shell p-n heterojunction with high specific surface area, tight surface contact and plentiful oxygen vacancies (OVs), MnO2@Co3O4 NWA|Ti possesses a strong visible light absorption, high charges transfer and separation ability. The proposed PEC sensor exhibited a wide linear range of 0.1–50000 nM and a low detection limit of 0.025 nM towards H2O2. Due to the rapid conversion of O2.- to H2O2 inside mitochondria, the PEC sensor can indirectly monitor the electron leakage in the ETC. Specifically, four selected mitochondrial inhibitors specifically inhibited the corresponding complex in mitochondria extracted from living HepG2 cells (hepatocellular carcinoma cells), and the H2O2 levels converted from O2.- was measured by the PEC sensor. It is evident that IQ (ubiquinone binding) site of complex I and Qo (ubiquinol oxidation) site of complex III are the key sites at which electron leakage occurred. This study could provide meaningful information for the diagnosis and treatment of certain disease caused by oxidative stress due to the electron leakage.

Colorimetric chemosensors for the selective detection of arsenite over arsenate anions in aqueous medium: Application in environmental water samples and DFT studies

Novel organic receptors N3R1- N3R3 were developed for the selective colorimetric recognition of arsenite ions in the organo-aqueous media. In the 50% aq. acetonitrile media and 70% aq. DMSO media, receptors N3R2 and N3R3 showed specific sensitivity and selectivity towards arsenite anions over arsenate anions. Receptor N3R1 showed discriminating recognition of arsenite in the 40% aq. DMSO medium. All three receptors formed a 1:1 complex with arsenite and stable for a pH range of 6–12. The receptors N3R2 and N3R3 achieved a detection limit of 0.008 ppm (8 ppb) and 0.0246 ppm, respectively, for arsenite. Initial hydrogen bonding on binding with the arsenite followed by the deprotonation mechanism was well supported by the UV–Vis titration, 1H- NMR titration, electrochemical studies, and the DFT studies. Colorimetric test strips were fabricated using N3R1- N3R3 for the on-site detection of arsenite anion. The receptors are also employed for sensing arsenite ions in various environmental water samples with high accuracy.

A Review of Anion Sensors: Progress and Prospects for Construction and Operation

The aim of this research paper is to offer an understanding of how anion sensing devices are constructed and operated. It will mainly focus on the practical aspects of anion sensing rather than the chemistry involved in designing molecules or receptors for the specific detection of anions. There are two main types of anion sensing, which are optical and electrical. This research paper will begin with a discussion on the construction and use of ion-sensitive electrodes and will progress to more complex devices such as CHEMFETs and ISFETs. Subsequently, this review will also examine optical sensors, including their basic principles, construction, and operation. Additionally, we will compare the relative advantages and disadvantages of optical sensors in comparison to electronic sensors. The objective of this research paper is to discuss the current use of anion sensors in the field and provide insights into potential future technologies and applications.

An amino-appended asymmetry salamo-type ratiometric fluorescent probe for efficient relay detection of B4O72−/HCHO in real samples

Development of fluorescent chemical sensors for ratiometric detection of multiple metal ions or anions are highly demanded, but there are still many challenges. Herein, an asymmetry salamo-type ratiometric fluorescent probe G1 were designed and synthesized for highly selective and sensitive detection of B4O72− and formaldehyde (HCHO). The introduction of B4O72− anion into salamo-type fluorescent probe solution induces a significant turn-off fluorescence behavior. Meanwhile, a strong fluorescence feature was again observed when HCHO was successively injected into the formed G1-B probe solution with turn-on style. 1H NMR titration and theoretical calculation proved that the B4O72- coordinates with phenolic oxygen and oxime nitrogen in fluorescent probe G1. B4O72− combination with probe G1 destroys the excited-state intramolecular proton transfer (ESIPT) process and causes fluorescence quenching effect. However, the addition of HCHO leads to a Cannizzaro disproportionation reaction occurred with the G1-B probe, resulting in the fluorescence recovery of the primitive probe molecule. Such probes have excellent selectivity and sensitivity for B4O72− and HCHO, in which the detection limit of sensor towards B4O72− and HCHO was 9.65×10−6 M and 4.66×10−11 M, respectively. Moreover, such sensor was successfully used for monitoring the concentration levels of B4O72− and HCHO in actual sample.

Associations of continuous anionic gap detection with the mortality in critically ill patients receiving renal replacement therapy

PurposeTo investigate the associations of anion gap (AG) levels before and 1-day after hemodialysis as well as anion gap changes with the mortality in critically ill patients receiving renal replacement therapy (RRT).MethodsTotally, 637 patients from MIMIC-III were included in this cohort study. The associations between AG (T0), AG (T1), or ∆AG [AG (T0) − AG (T1)], and the risk of 30-day or 1-year mortality were examined by Cox restricted cubic spline regression models. Univariate and multivariate Cox proportional-hazards model was applied to assess the associations between AG (T0), AG (T1), ∆AG with 30-day and 1-year mortality, respectively.ResultsThe median follow-up time was 18.60 (8.53, 38.16) days and 263 (41.3%) patients were survived. There was a linear relationship between AG (T0), AG (T1) or ∆AG and the risk of 30-day or 1-year mortality, respectively. The risk of 30-day mortality was higher in AG (T0) > 21 group (HR = 1.723, 95% CI 1.263–2.350), and AG (T1) > 22.3 group (HR = 2.011, 95% CI 1.417–2.853), while lower in AG > 0 group (HR = 0.664, 95% CI 0.486–0.907). The risk of 1-year mortality was increased in AG (T0) > 21 group (HR = 1.666, 95% CI 1.310–2.119), and AG (T1) > 22.3 group (HR = 1.546, 95% CI 1.159–2.064), while decreased in AG > 0 group (HR = 0.765, 95% CI 0.596–0.981). Patients with AG (T0) ≤ 21 had higher 30-day and 1-year survival probability than those with AG (T0) > 21.ConclusionAG before and after dialysis as well as the changes of AG were important factors associated with the risk of 30-day and 1-year mortality in critically ill patients receiving RRT.

Antimonene quantum dots as bifunctional fluorescent sensors for rapid detection of cation (Fe3+) and anions (CrO42−, Cr2O72−)

As an emerging bandgap material, antimonene quantum dots (AQDs) have attracted much attention due to their unique structure and outstanding physical and chemical properties. However, the research on the optical properties of AQDs is still in the initial stage and needs further exploration. Herein, the fluorescent AQDs were synthesized by ultrasonic liquid-phase exfoliation, combined with a hydrothermal treatment process. The as-prepared AQDs exhibit good fluorescence characteristics and have a fluorescence quantum yield value of 7.56%. Besides, the AQDs show good stability under different salt concentrations. Especially, the AQDs show high selectivity and rapid detection of Fe3+, CrO42−, and Cr2O72− ions in an aqueous solution with good anti-interference ability. The relatively low limit of detection for Fe3+ based on AQDs was 6.85 µM, and the limits of detection for CrO42−, and Cr2O72− were 23.0 and 5.91 µM, respectively. The mechanism for the fluorescence quenching of the AQDs can be attributed to the synergistic effect of the internal filter effect and the oxidation–reduction reaction between the AQDs and analytes. This work provided a simple synthesis method to easily prepare the AQDs with a larger yield, which can be applied to rapidly detect Fe3+ cation, and CrO42−, and Cr2O72− anions.

A Novel L-Arginine Functionalized CdTe Quantum Dots Fluorescence Probe for Pyrophosphate Anion Detection.

In this paper, a novel amino acid surface-functionalized semiconductor CdTe quantum dot fluorescent probe amidated by carboxyl and amide groups was synthesized to detect pyrophosphate ions (P2O74-, PPi). L-Arginine (L-Arg) was grafted onto cysteine modified CdTe quantum dots (Mea-CdTe QDs) to form a new L-Arginine-functionalized quantum dot fluorescent probe (L-Arg@Mea-CdTe). The prepared probe has good optical properties with multiple grafted functional groups on the surface. The guanidine group of the L-Arg@Mea-CdTe fluorescent probe is strongly basic and will be fully protonated under physiological conditions. The resulting hydrogen bonds bound to pyrophosphate lead to significant changes in the fluorescence of CdTe quantum dots. IR and XPS characterization were performed to confirm it. The addition of PPi induces a significant fluorescence quenching of L-Arg@Mea-CdTe in aqueous solution. The fluorescent QDs probe can also detect pyrophosphate with good sensitivity and anti-interference performance. The detection limit of the L-Arg@Mea-CdTe fluorescence probe for PPi is as low as 0.30μM. In addition, the novel nano-fluorescent probe was successfully applied to detect PPi in water and in cell imaging.

Nanomolar pyrophosphate detection in water using a zinc-terpyridine receptor and its applications in antiproliferative and antioxidant activity

A new fluorescent 4′-(3,4-diethoxyphenyl)-2,2′:6′,2′'-terpyridine ligand L and its 1:1 zinc complex ZnCl2L have been synthesized, characterized with the help of NMR, Mass spectroscopy, CHN analysis, and DFT study. In-situ prepared non-fluorescent ZnCl2L receptor was utilized for selective detection of pyrophosphate anion (P2O74-, PPi) in water (10 mM HEPES buffer, pH 7.4) in the vicinity of other competing analytes (10 equivalents of HPO42-, H2PO4-, CO32–, HCO3–, Cl−, OH–, Br−, CH3CO2–, F−, I-, NO3–, SO42-, SO32-, S2O32-, N3–) by employing UV–Visible spectroscopy and fluorescence “ON–OFF–ON” mechanism. ZnCl2L receptor formed a fluorescent 2:1 adduct with PPi in water during its detection at a nanomolar concentration (LOD ∼27.89 nM). The receptor is also successfully employed in low-cost PPi detection through real-time easily accessible paper strip application. Further, ZnCl2L exhibited significant cytotoxic activity against MDAMB-231 cells with an IC50 value of 53.85 µM and excellent antioxidant activity having an antioxidant percentage of 73.75%.

Determination of Cations and Anions in Desulfurization Waste Water of Coal-Fired Power Plant by Ion Chromatography.

The reliable and accurate determination of corrosive anions at sub- to low-μg/L levels is a challenging analytical problem. In this manuscript, a simultaneous determination method of cations and anions in power plant water samples was established by large volume injection ion chromatography. The analytical parameters including separation column, the suppressor current and the elute concentration were optimized. Results showed good separation under the optimum conditions, and the calibration curves of all analytes were linear with good coefficient of determination (r2) >0.997, and the mean recoveries for all analytes ranged from 75.62 to 118.58% with RSD of 0.07-4.83%. The established method was successfully applied to determine the cations and anions in realwaste water samples from coal-fired power, and was verified by inductively coupled plasma optical emission spectrometry and electrometric titration. The relative deviation between methods was all below 6.72%, which indicated good accuracy of the established ion chromatography method. The results could also provide reference for the precise and rapid detection of cations and anions in environmental water samples.

An amphiphilic macrocyclic acylhydrazone dimer: Facile synthesis and dual channel detection and removal of phthalate anion

Despite the large number of dicarboxylates’ receptors, the dual channel ones capable of recognizing and removing of phthalate anion are rare and the task remains challenging. In this paper, a facilely synthesized amphiphilic macrocyclic acylhydrazone dimer (AMAD) can not only detect phthalate anion selectively, through both color changes and turn-on fluorescence in solution as well as in solid state, but is also able to remove it from either water or organic solvents. The current study paves the way for the search of more multiple functional receptors of dicarboxylates anions.

A versatile AIE probe with mitochondria targeting for dual-channel detection of superoxide anion and viscosity

Abnormal viscosity and excessive superoxide anion (O2•-) levels in living cells often cause a series of biological dysfunction and oxidative damage. However, a great challenge remains in quickly and conveniently detecting the viscosity and O2•- levels in living cells. Herein, we fabricated a versatile aggregation-induced emission (AIE) probe with mitochondria targeting, DTPB, for dual-imaging of viscosity and O2•- level in living cells with two different channels. The obtained DTPB contained a diphenyl phosphinic acid unit responsive to O2•-, a unit with twisted intramolecular charge trans (TICT) function responsive to viscosity, and a pyridine cation unit with mitochondria targeting. The results showed that DTPB exhibited a remarkable response to viscosity with a near-infrared emission peak at 671 nm and was highly sensitive to O2•- levels with an emission peak at 587 nm. The dual-channel probe has great application prospects in the visual diagnosis of cancer and related diseases.

Urea- and Thiourea-Based Receptors for Anion Binding.

ConspectusOver the past five decades, significant progress has been made in the field of anion recognition with a diverse variety of synthetic receptors because of the fundamental importance of anions in chemical, environmental, and biological processes. In particular, urea- and thiourea-based molecules offering directional binding sites are attractive receptors for anions due to their ability to bind anions employing primarily hydrogen-bonding interactions under neutral conditions and have gained a recent paramount attention in the area of supramolecular chemistry. The presence of two imine (-NH) groups on each urea/thiourea functionality in these receptors gives them potential for excellent binding of an anion, mimicking the natural binding process in living cells. The increased acidity offered by thiocarbonyl groups (C═S) in a thiourea-functionalized receptor could enhance its anion binding ability as compared to its analogous urea-based receptor containing a carbonyl (C═O) group. During the last several years, our group has been involved in exploring a wide variety of synthetic receptors, and we have studied them with anions experimentally and computationally. In this Account, we will highlight the overall summary of our group's efforts focusing on anion coordination chemistry of urea- and thiourea-based receptors with varying linkers (rigid and flexible), dimensions (dipodal and tripodal), and functionalities (bifunctional, trifunctional, and hexafunctional). Depending on the linkers and attached groups, bifunctional-based dipodal receptors can bind anions forming 1:1 or 1:2 complexes. A dipodal receptor with flexible aliphatic or rigid m-xylyl linkers forms a cleft to bind a single anionic species in the pocket. However, a dipodal receptor with p-xylyl linkers binds anions in both 1:1 and 1:2 binding modes. As compared to a dipodal receptor, a tripodal receptor provides a more organized cavity for an anion, forming predominantly a 1:1 complex, while the binding strength and selectivity are influenced by linking chains and terminal groups. A hexafunctional-based tripodal receptor bridged with o-phenylene groups provides two clefts that can host two small anions or one large anion. However, a hexafunctional receptor with p-phenylene groups as linkers binds two anions, one at an inner pocket and the other at an outer pocket. It was shown that the presence of suitable chromophores at the terminal groups makes the receptor useful for the naked-eye detection for certain anions (e.g., fluoride, acetate) in solution. The field of anion binding chemistry is rapidly growing, and this Account aims to provide fundamental aspects influencing the binding strength and selectivity of anionic species with abiotic receptors which might eventually be useful for the development of new devices for binding, sensing, and separating biologically and environmentally important anions.

Novel fluorescent probe for sequential recognition of Zn2+ and pyrophosphate in aqueous based on aggregation-induced emission

A new fluorescent probe (E)-4-(4-([2,2′:6′,2′'-terpyridin]-4′-yl)styryl)-1-dodecylpyridin-1-ium (TPy-SD), with the aggregation-induced emission (AIE) property in aqueous solution, has been synthesized and characterized. The new probe, TPy-SD exhibited excellent selectivity and sensitivity towards Zn2+ with a relatively low detection limit (1.76 × 10−7 M). The addition of Zn2+ is thought to disrupt the AIE property of TPy-SD, thereby leading to a fluorescence blue shift. Interestingly, the complex of probe TPy-SD with Zn2+ (Zn (II) TPy-SD), with molar ratio of 1:1, can be used as a simple, sensitive, and rapid means for the detection of pyrophosphates (PPi) in solution (water/DMSO = 99:1). As evidenced by transmission electron microscopy (TEM), dynamic light scattering (DLS) and fluorescence emission spectroscopy, this detection is thought to be due to the strong affinity between PPi and Zn2+, which brings out Zn2+ from the coordination cavity of chemical sensor TPy-SD, thus realizing the detection and recognition of PPi. Therefore, the new AIE fluorescent probe can be used as a dual probe for the detection of cations and anions.

Fluorophore molecule loaded in Tb-MOF for dual-channel fluorescence chemosensor for consecutive visual detection of bacterial spores and dichromate anion

Developing multifunctional luminescent switches for detecting various poisons are urgent given the continuous deterioration of the environment. Herein, a new porous fluorescent metal–organic framework [Tb2(TPTC)(DMA)4(NO3)2]n(HPU-25) was initially designed. Then, fluorophore molecule tris(2,2′-bipyridine) dichlororuthenium(II) hexahydrate (Ru(bpy)32+) was loaded onto HPU-25 by a simple post-synthesis strategy to prepare a new ratio fluorescence sensor Ru(II)@HPU-25. As a sensor, it can detect 2,6-pyridinedicarboxylic acid (DPA) content in real-time, with high sensitivity and selectivity, without being disturbed by probe concentration and environment. Evident changes in fluorescence color and intensity are observed in distinguishing DPA contents. In addition, after detecting DPA, it can be used for consecutive visual detection of dichromate anion (Cr2O72−) in water. This multifunctional fluorescence sensor could make up for the defects of single fluorescence and single function of the traditional fluorescence sensor by using the dual strategies of ratio sensing and cascade sensing. Interestingly, DPA and Cr2O72− in samples can be visually detected rapidly in real-time through the chroma acquisition APP on smartphone. More importantly, we also designed the combination of two logic gate operations for sensing the two targets. In the poison detection in daily life, these intelligent applications of fluorescence sensors have a broad development space.

Light-controlled detection of aromatic carboxylate anions using doubly fused naphthopyran derivative

A photochromic naphthopyran derivative, 2,2,11,11-tetraphenyl-2,11-dihydrobenzo[f]pyrano[3,2-h]chromene has been synthesized and its structure was confirmed using various spectroscopic techniques like NMR, infrared spectroscopy (FT-IR), high-resolution mass spectroscopy (HR-MS) and single crystal X-ray diffraction (SCXRD). The synthesized probe has shown a sensitive signal toward salicylic acid and 3,5-diaminobenzoic acid in acetonitrile: water (50:50(v:v)) solvent system at pH 7.6 (1 mM Tris buffer). UV–vis and fluorescence spectroscopic analyses revealed complex formation between these carboxylate anions and the synthesized photochromic probe, with blue shifts in absorption bands & enhancement in fluorescence intensity. Furthermore, photo-switching for the naphthopyran derivative in presence of both carboxylic acids was performed using 365 nm UV light, and results obtained indicated that the release and binding of these carboxylic acids can be controlled using 365 nm UV light. As expected, the fluorescence analysis provided a better limit of detection value as compared to the UV–Vis analysis. Fluorescence spectroscopy yielded a detection limit of 16.29 nM for salicylate ions using the naphthopyran-based probe.

Development and Application of Ruthenium(II) and Iridium(III) Based Complexes for Anion Sensing.

Improvements in the design of receptors for the detection and quantification of anions are desirable and ongoing in the field of anion chemistry, and remarkable progress has been made in this direction. In this regard, the development of luminescent chemosensors for sensing anions is an imperative and demanding sub-area in supramolecular chemistry. This decade, in particular, witnessed advancements in chemosensors based on ruthenium and iridium complexes for anion sensing by virtue of their modular synthesis and rich chemical and photophysical properties, such as visible excitation wavelength, high quantum efficiency, high luminescence intensity, long lifetimes of phosphorescence, and large Stokes shifts, etc. Thus, this review aims to summarize the recent advances in the development of ruthenium(II) and iridium(III)-based complexes for their application as luminescent chemosensors for anion sensing. In addition, the focus was devoted to designing aspects of polypyridyl complexes of these two transition metals with different recognition motifs, which upon interacting with different inorganic anions, produces desirable quantifiable outputs.

Liver-Targeted Near-Infrared Fluorescence/Photoacoustic Dual-Modal Probe for Real-Time Imaging of In Situ Hepatic Inflammation.

Early diagnosis of hepatic inflammation is the key to timely treatment and avoid the worsening of liver inflammation. Near-infrared fluorescence (NIRF) probes have high sensitivity but low spatial resolution in lesion imaging, while photoacoustic (PA) imaging has good spatial location information. Therefore, the development of a NIRF/PA dual-modal probe integrated with high sensitivity and spatial location feedback can achieve an accurate early diagnosis of hepatic inflammation. Here, we report an activatable NIRF/PA dual-modal probe (hCy-Tf-CA) for the detection of the superoxide anion (O2·-) in early hepatic inflammation. hCy-Tf-CA showed high selectivity and sensitivity for detecting O2·- fluctuation in vitro. More importantly, by introducing hepatocyte-targeting cholic acid (CA), the probe successfully achieved accurate in situ imaging of acute inflammatory liver injury (AILI) and autoimmune hepatitis (AIH) in vivo. The introduced CA not only promotes the hepatic targeting accumulation of probes but also improves the performance of low background dual-modal imaging in vivo. Therefore, hCy-Tf-CA provides an effective strategy for significantly improving in situ imaging performance and holds great potential for early, sensitive, and accurate diagnosis of hepatic inflammation.

Turn-on fluorescence detection of specific inorganic anions by Zr(IV)-MOF with amino-functional group

Turn-on fluorescence detection of specific inorganic anions by Zr(IV)-MOF with amino-functional group

Protective Effect of Sulforaphane on Oxidative Stress and Mitochondrial Dysfunction Associated with Status Epilepticus in Immature Rats

The present study aimed to elucidate the effect of sulforaphane (a natural isothiocyanate) on oxidative stress and mitochondrial dysfunction during and at selected periods following status epilepticus (SE) induced in immature 12-day-old rats by Li-pilocarpine. Dihydroethidium was employed for the detection of superoxide anions, immunoblot analyses for 3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE) levels and respiratory chain complex I activity for evaluation of mitochondrial function. Sulforaphane was given i.p. in two doses (5 mg/kg each), at PD 10 and PD 11, respectively. The findings of the present study indicate that both the acute phase of SE and the early period of epileptogenesis (1 week and 3 weeks following SE induction) are associated with oxidative stress (documented by the enhanced superoxide anion production and the increased levels of 3-NT and 4-HNE) and the persisting deficiency of complex I activity. Pretreatment with sulforaphane either completely prevented or significantly reduced markers of both oxidative stress and mitochondrial dysfunction. Since sulforaphane had no direct anti-seizure effect, the findings suggest that the ability of sulforaphane to activate Nrf2 is most likely responsible for the observed protective effect. Nrf2-ARE signaling pathway can be considered a promising target for novel therapies of epilepsy, particularly when new compounds, possessing inhibitory activity against protein–protein interaction between Nrf2 and its repressor protein Keap1, with less “off-target” effects and, importantly, with an optimal permeability and bioavailability properties, become available commercially.

A Near-Infrared Fluorescent Probe for Recognition of Hypochlorite Anions Based on Dicyanoisophorone Skeleton.

A novel near-infrared (NIR) fluorescent probe (SWJT-9) was designed and synthesized for the detection of hypochlorite anion (ClO-) using a diaminomaleonitrile group as the recognition site. SWJT-9 had large Stokes shift (237 nm) and showed an excellent NIR fluorescence response to ClO- with the color change under the visible light. It showed a low detection limit (24.7 nM), high selectivity, and rapid detection (within 2 min) for ClO-. The new detection mechanism of SWJT-9 on ClO- was confirmed by 1H NMR, MS spectrum, and the density functional theory (DFT) calculations. In addition, the probe was successfully used to detect ClO- in HeLa cells.