A novel glutathione-triggered theranostic prodrug for anticancer and imaging in living cells

A novel theranostic prodrug was designed and synthesized by conjugating a naphthalimide derivative with vitamin D₂via a disulfide linker. The prodrug featured a highly selective detection process for glutathione (GSH) and showed a red-shifted fluorescence within 30 min. Notably, it also exhibited antitumor activity similar to vitamin D₂ and could be monitored by cellular imaging.

A novel glutathione-triggered theranostic prodrug was synthesized by conjugating the naphthalimide chromophore and vitamin D₂via a disulfide bond.     

A mitochondrial-targetable dual functional near-infrared fluorescent probe to monitor pH and H2O2 in living cells and mice

A lower pH level and high hydrogen peroxide (H₂O₂) concentration in mitochondria is closely associated with a variety of diseases including cancer and inflammation. Thus, determination of changes in the level of acidic pH and H₂O₂ is of great importance and could provide new insights into the key functions under both physiological and pathological conditions. Herein, we present a novel mitochondria-targetable probe NIR-pH-H₂O₂, as the first near infrared (NIR) fluorescent small molecule, to monitor changes of endogenous pH (pk_a = 6.17) and H₂O₂ with high sensitivity, good compatibility and low cytotoxicity. Futhermore, it was successfully employed to monitor pH and H₂O₂ in a mouse acute inflammation model. These results demonstrate that NIR-pH-H₂O₂ is a novel bifunctional mitochondrial-targeted NIR probe to sense acidic pH and H₂O₂in vitro and in vivo, indicating its huge potential for the diagnosis of pH and H₂O₂-related diseases.

A lower pH level and high hydrogen peroxide (H₂O₂) concentration in mitochondria is closely associated with a variety of diseases including cancer and inflammation.     

A real-time ratiometric fluorescent probe for imaging of SO2 derivatives in mitochondria of living cells

A real-time ratiometric fluorescent probe (IN-CZ) for highly selective detection of sulfite was designed and synthesized, which is based on modulating the intramolecular charge transfer (ICT) of the hemicyanine dye platform. The mechanism of using the probe is mainly through the Michael addition that occurs between IN-CZ and sulfite with a detection limit of 2.99 × 10⁻⁵ M. IN-CZ displays a fast response (within 1 minute) and is highly selective for SO₃²⁻/HSO₃⁻ over ROS, biologically relevant ions, biological mercaptans and other reactive species. More importantly, IN-CZ was suitable for ratiometric fluorescence imaging in living cells, by real-time monitoring of SO₃²⁻/HSO₃⁻ changes in mitochondria targeted in living cells.

A real-time ratiometric fluorescent probe (IN-CZ) for highly selective detection of sulfite was designed and synthesized, which is based on modulating the intramolecular charge transfer of the hemicyanine dye platform.     

Construction of a lysosome-targetable ratiometric fluorescent probe for H2O2 tracing and imaging in living cells and an inflamed model

Hydrogen peroxide (H₂O₂), an important reactive oxygen species (ROS) with unique destructive oxidation properties, can be produced in lysosomes to fight off pathogens. Although many fluorescent probes have been developed for the detection and imaging of H₂O₂, the development of a ratiometric fluorescent probe for H₂O₂ detection and imaging in lysosomes and an inflammation model remains rather scarce. Therefore, it is important to develop an efficient tool for monitoring H₂O₂ in inflamed tissues to evaluate the physiological and pathological relationship between inflammation and lysosomal H₂O₂. In this work, a new naphthalimide-based lysosome-targeting fluorescent probe (NPT-H₂O₂) for ratiometric detection and imaging was developed in vitro and in vivo. The probe exhibited two well-resolved emission peaks separated by 125 nm, rapid response (<40 s), and high selectivity and sensitivity toward H₂O₂, as well as low cytotoxicity in vitro. Inspired by prominent features of these results, we further successfully applied NPT-H₂O₂ for H₂O₂ imaging with a dual-channel in living cells, demonstrating that our probe NPT-H₂O₂ was targeted in the lysosomes. Finally, NPT-H₂O₂ was used for H₂O₂ detection in inflamed tissues and achieved satisfactory results. We predict that our probe can be used as a powerful tool to reveal the relationship between physiology and pathology of inflammation and lysosomal H₂O₂.

Hydrogen peroxide (H₂O₂), an important reactive oxygen species (ROS) with unique destructive oxidation properties, can be produced in lysosomes to fight off pathogens.     

H2O2 induces DNA repair in mononuclear cells: evidence for association with cytosolic Ca2+ fluxes

Cellular DNA repair systems are induced whenever DNA is damaged. Reactive oxygen species (ROS) are generated, in vivo, in the tissues as a result of regular cellular metabolism or after exposure to oxidizing agents, such as ultraviolet (UV) irradiation. It has been suggested that ROS mediate DNA damage. The objectives of the study were as follows: (1) to investigate whether hydrogen peroxide (H2O2), the commonly occurring cellular ROS, induces DNA repair as a response to the damage it probably causes; (2) to evaluate whether H2O2-induced DNA repair, if present, is signaled through a Ca2(+)-dependent pathway via the tyrosine kinase signal transduction. H2O2 was found to induce DNA repair in human peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. The recovery of RNA synthesis, which occurred after DNA repair, confirmed that transcribable DNA was repaired. The inhibition of tyrosine kinase activity by genistein reduced the DNA repair significantly. Furthermore, H2O2 caused a dose-dependent significant rise in cytosolic calcium ((Ca2+)i). H2O2 also induced a small rise in (Ca2+)i of cytosolic Ca2(+)-depleted cells, probably reflecting the release of Ca2+ from internal stores. Genistein inhibited both Ca2+ influx and Ca2+ release from internal stores. In summary, H2O2 induced a DNA repair synthesis that was in part Ca2+ dependent and signaled via tyrosine kinase. The changes in DNA repair paralleled changes in (Ca2+)i. The H2O2-induced (Ca2+)i rise was mostly the result of influx, but to some degree it was also due to the translocation of Ca2+ from internal stores.     

Donor-derived b2a2-specific T cells for immunotherapy of patients with chronic myeloid leukemia

The BCR-ABL fusion proteins, b2a2 and b3a2, are potential targets for a beneficial graft-versus-leukemia (GVL) effect after allogeneic stem cell transplantation for chronic myeloid leukemia (CML). This study demonstrates that CD4+ T cells specific to the b2a2 peptide can be generated from a normal allogeneic stem cell transplant donor after stimulation with monocyte-derived dendritic cells (Mo-DC) using culture conditions applicable to clinical use. Stimulation of donor T-cell enriched mononuclear cells (MNC) with b2a2-pulsed Mo-DC produced approximately 3 x 10(9) b2a2-specific CD4+ T cells. The CD4+ T cells were HLA-DR7 restricted. These results confirm that the generation of donor derived b2a2-specific T cells for clinical use is feasible and warrants clinical testing after stem cell transplantation.     

束缚应激状态下大鼠腹腔巨噬细胞释放一氧化氮及肿瘤坏死因子α和H2O2的变化

目的:检测牙龈卟啉菌内毒素穴Pg-LPS雪刺激大鼠腹腔巨噬细胞所释放的NO、肿瘤坏死因子α和H2O2是否受到束缚应激的影响。方法:实验于2005-09/2006-02在福建医科医科大学口腔医学院和福建中西医结合研究院实验室进行。①分组:取14只SPF级雄性SD大鼠随机分为正常组及应激组,每组7只。②造模:正常组不加刺激,应激组大鼠置于特制的圆柱形筒内,于实验开始最初3d每日9:00～15:00被置于束缚筒6h,3d后于每日9:00至次日9:00被置于束缚筒24h,正常饲养24h后再应激24h,如此循环直至实验结束。③观察指标:观察造模12d后两组大鼠体质量变化,并及时处死,收集腹腔液,计数巨噬细胞总量。贴壁后的巨噬细胞分成2组分别继续用RPMI-1640培养液和RPMI-1640培养液 1mg/LPg-LPS继续培养,24h后分别收集上清,观察无刺激组、单纯Pg-LPS组、单纯应激组和应激 Pg-LPS组上清液中NO,H2O2和肿瘤坏死因子α水平。结果:14只大鼠全部进入结果分析。①实验完成时应激组大鼠体质量低于正常组眼穴162.14±17.53雪熏穴263.57±19.94雪g熏P<0.05演。②应激组大鼠腹腔巨噬细胞总量低于正常组眼穴9.49±2.75雪×106熏穴31.47±8.00雪×106熏P<0.01演。③NO浓度押单纯Pg-LPS组显著高于无刺激组眼穴265.69±10.86雪熏穴239.40±12.07雪μmol/L,P<0.05演;应激 Pg-LPS组显著高于无刺激组和单纯应激组眼穴257.57±12.43雪熏穴239.40±12.07雪,穴243.32±13.94雪μmol/L,P<0.05演。④H2O2浓度:单纯应激组和应激 Pg-LPS组显著高于无刺激组眼穴7.14±1.04雪熏穴7.54±1.15雪,穴5.27±1.02雪μmol/L,P<0.05演。⑤肿瘤坏死因子α水平:应激 Pg-LPS组显著高于无刺激组眼穴16.81±4.76雪熏穴8.38±0.93雪ng/L熏P<0.05演。结论:①束缚应激可改变巨噬细胞对牙龈卟啉菌内毒素刺激的反应,引起大鼠腹腔巨噬细胞功能紊乱。②应激作为一种不良刺激因素,可以和牙龈卟啉菌内毒素一起发生协同作用,引起炎症反应发生。     

束缚应激状态下大鼠腹腔巨噬细胞释放一氧化氮及肿瘤坏死因子α和H2O2的变化

目的：检测牙龈卟啉菌内毒素（Pg-LPS）刺激大鼠腹腔巨噬细胞所释放的NO、肿瘤坏死因子α和H2O2是否受到束缚应激的影响。 方法：实验于2005-09／2006-02在福建医科医科大学口腔医学院和福建中西医结合研究院实验室进行。①分组：取14只SPF级雄性SD大鼠随机分为正常组及应激组，每组7只。②造模：正常组不加刺激，应激组大鼠置于特制的圆柱形筒内，于实验开始最初3d每日9：00～15：00被置于束缚筒6h，3d后于每日9：00至次日9：00被置于束缚筒24h，正常饲养24h后再应激24h，如此循环直至实验结束。③观察指标：观察造模12d后两组大鼠体质量变化，并及时处死，收集腹腔液，计数巨噬细胞总量。贴壁后的巨噬细胞分成2组分别继续用RPMI-1640培养液和RPMI-1640培养液＋1mg／L Pg-LPS继续培养，24h后分别收集上清，观察无刺激组、单纯Pg-LPS组、单纯应激组和应激＋Pg-LPS组上清液中NO，H2O2和肿瘤坏死因子③水平。 结果：14只大鼠全部进入结果分析。①实验完成时应激组大鼠体质量低于正常组[（162．14&;#177;17．53），（263．57&;#177;19．94）g，P〈0．05]。②应激组大鼠腹腔巨噬细胞总量低于正常组[（9．49&;#177;2．75）&;#215;10^6，（31．47&;#177;8．00）&;#215;10^6，P〈0．01]。③NO浓度：单纯Pg-LPS组显著高于无刺激组[（265．69&;#177;10．86），（239．40&;#177;12．07）μmol／L，P〈0．05]；应激＋Pg-LPS组显著高于无刺激组和单纯应激组[（257．57&;#177;12．43），（239．40&;#177;12．07），（243．32&;#177;13．94）μmol／L，P〈0．05]。（4）H2O2浓度：单纯应激组和应激＋Pg-LPS组显著高于无刺激组[（7．14&;#177;1．04），（7．54&;#177;1．15），（5．27&;#177;1．02）μmol／L，P〈0．05]。⑤肿瘤坏死因子α水平：应激＋Pg-LPS组显著高于无刺激组[（16．81&;#177;4．76），（8．38&;#177;0．93）ng／L，P〈0．05]。 结论：①束缚应激可改变巨噬细胞对牙龈卟啉菌内毒素刺激的反应，引起大鼠腹腔巨噬细胞功能紊乱。②应激作为一种不良刺激因素，可以和牙龈卟啉菌内毒素一起发生协同作用，引起炎症反应发生。     

Signaling in H2O2-induced increase in cell proliferation in Barrett's esophageal adenocarcinoma cells

Mechanisms whereby acid reflux may accelerate the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. We have previously shown that NADPH oxidase NOX5-S generates reactive oxygen species (ROS) when Barrett's metaplastic cells are exposed to acid. Besides metaplastic cells, other H(2)O(2)-producing cells (e.g., inflammatory cells) present in BE mucosa may produce additional ROS, which may also affect metaplastic cells contributing to esophageal tumorigenesis. In this study, we investigate whether exogenous H(2)O(2) stimulates cell proliferation by increasing NOX5-S expression. Low dose (10(-13) M) of H(2)O(2) significantly increased thymidine incorporation, NOX5-S mRNA, and protein expression in a Barrett's EA cell line FLO. H(2)O(2)-induced increase in NOX5-S expression was significantly inhibited by knockdown of nuclear factor (NF)-κB1 p50 with p50 small interfering RNA (siRNA) in EA cell lines FLO and OE33. H(2)O(2) significantly increased p65 phosphorylation and the luciferase activity in FLO cells transfected with a NF-κB activation reporter plasmid pNF-κB-Luc. H(2)O(2)-induced increase in luciferase activity in FLO cells was significantly decreased by knockdown of extracellular signal-regulated kinase 2 (ERK2) mitogen-activated protein kinase (MAPK). Overexpression of p50 and p65 remarkably increased the luciferase activity in FLO cells transfected with a NOX5-S reporter plasmid NOX5-LP. In addition, H(2)O(2)-induced thymidine incorporation in FLO cells was significantly decreased by the MAPK kinase 1/2 inhibitor 2'-amino-3'methoxyflavone (PD98059) and ERK2 siRNA but not by ERK1 siRNA. Likewise, H(2)O(2)-induced increase in NOX5-S expression was significantly decreased by ERK2 siRNA in FLO and OE33 cells. We conclude that a low dose of H(2)O(2) increases cell proliferation. H(2)O(2)-induced increase in cell proliferation may depend on sequential activation of ERK2 MAPK, NF-κB1 p50, and NOX5-S.     

A benzothiazole-based new fluorogenic chemosensor for the detection of CN− and its real-time application in environmental water samples and living cells

Since the cyanide ion is used in a wide range of industries and is harmful to both human health and the environment, a number of research efforts are dedicated to creating fluorescence sensors for the detection of cyanide (CN⁻). Herein, for the fluorescence detection of CN⁻, a new highly selective and sensitive sensor 2-(3-(benzo[d]thiazol-2-yl)-4-hydroxybenzylidene)-1H-indene-1,3(2H)-dione (BID) was created by conjugating a benzothiazole moiety with 1H-indene-1,3(2H)-dione. The donor and acceptor components of this hybrid receptor were covalently connected through a double bond. The nucleophilic addition of a cyanide anion to the BID inhibits the intramolecular charge transfer (ICT) transition, resulting in spectral and colour alterations in the receptor. When the solvent polarity was increased from n-hexane to methanol, this molecule exhibited a bathochromic shift in the emission wavelength (610 to 632 nm), suggesting the presence of a solvatochromic action. The sensor BID has shown strong specificity towards CN⁻ by interrupting its internal charge transfer (ICT), resulting in a significant change in the UV-vis spectrum and a notable blue shift in the fluorescence emission spectrum. The cyanide anion (CN⁻) is responsible for the optical alterations observed by BID, as opposed to the other anions examined. The detection limit was 5.97 nM, significantly less than the WHO''s permitted amount of CN⁻ in drinking water. The experimental findings indicate that BID''s fluorescence response to CN⁻ is pH insensitive throughout a wide pH range of 6.0 to 12.0. The interaction mechanism between the BID and CN⁻ ions has been studied by HRMS, ¹H-NMR titration experiments, FT-IR, and DFT, which confirmed the nucleophilic addition of CN⁻ on vinylidene and subsequent disturbance of ICT. Additionally, we demonstrated the real-time detection application of CN⁻ in environmental water samples and live-cell imaging.

Since the cyanide ion is used in a wide range of industries and is harmful to both human health and the environment, a number of research efforts are dedicated to creating fluorescence sensors for the detection of cyanide (CN⁻).     

A MnO2–[Ru(dpp)3]Cl2 system for colorimetric and fluorimetric dual-readout detection of H2O2

Two-dimensional (2D) MnO₂ nanosheets were synthesized by a template-free and one-step route, and the dye [Ru(dpp)₃]Cl₂ was linked onto the MnO₂ nanosheet surface via electrostatic interaction. The formed MnO₂–[Ru(dpp)₃]Cl₂ hybrid was used for a dual optical detection for H₂O₂, an important reactive oxygen species (ROS). Upon addition of H₂O₂, the reaction of MnO₂ with H₂O₂ results in the dissolution of MnO₂ nanosheets and simultaneous generation of O₂. The fading of the solution and simultaneous fluorescence change of [Ru(dpp)₃]Cl₂, sensitive to O₂, enables colorimetric and fluorimetric dual-mode detection of H₂O₂. The dual-output assay in a single probe provides a good sensitivity with a detection limit of 0.18 μM H₂O₂. The dual-signal strategy can efficiently overcome the shortcoming of the single detection mode, and improve the detection accuracy by an additional correction of output signals from each other. Moreover, the successful determination of H₂O₂ in the serum samples demonstrates the potential applicability of the MnO₂–[Ru(dpp)₃]Cl₂ based probe in biosensing and bioanalysis.

The MnO₂ nanosheets with anchored [Ru(dpp)₃]Cl₂ were prepared for colorimetric and fluorimetric dual-mode detection of H₂O₂.     

Synthesis of caffeic acid sulfonamide derivatives and their protective effect against H2O2 induced oxidative damage in A549 cells

Exogenous antioxidants are considered as important therapeutic tools for oxidative stress associated disorders as they can regulate the redox state, which is associated with cell and organ function. Inspired by natural polyphenols, six new caffeic acid sulfonamide derivatives were synthesized by coupling sulfonamides to the backbone of caffeic acid with good yields. Their structure and lipophilicity were characterized by 1H nuclear magnetic resonance (NMR), ¹³C{¹H} NMR, infrared spectroscopy (IR) and oil–water partition coefficient assay. Their free radical scavenging activity and antioxidant activity were assessed by DPPH assay and hydrogen peroxide (H₂O₂) induced oxidative stress in human lung carcinoma A549 cells. The oil–water partition coefficient results indicate that the conjugation of sulfonamides increases the lipophilicity of caffeic acid. The CASMD, CASDZ and CASN results show higher free radical scavenging effects compared with vitamin C. The derivatives do not show any inhibitory effect on the proliferation of A549 cells up to a concentration of 200 μM, except CASDZ which significantly inhibits the growth of A549 cells at a concentration of 200 μM. In addition, the obtained derivatives markedly attenuate H₂O₂ induced decrease of cell viability, inhibit the production of ROS and MDA, and promote the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). Besides, treatment of H₂O₂ stimulated A549 cells with caffeic acid sulfonamide derivatives further increases mRNA expression of NF-E2-related factor 2 (Nrf2) and its target genes, including heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1) and thioredoxin reductase 1 (TXNRD1). These results suggest that these new caffeic acid sulfonamide derivatives have higher lipophilicity and better antioxidant activities than the parent caffeic acid, and they might be able to control the antioxidant response in cells via the Nrf2 pathway.

Synthesized caffeic acid derivatives exhibit protective effect on H₂O₂ induced oxidative injury in A549 cells via Nrf2 pathway.     

A two-photon lysosome-targeted probe for endogenous formaldehyde in living cells

Formaldehyde (FA) is a gaseous signaling molecule that plays a vital role in various biological processes as well as neurodegenerative diseases. Therefore, it is of great practical significance to develop effective and reliable chemical sensors for the monitoring of endogenous FA. Here, we designed and synthesized a two-photon (810 nm) turn-on chemosensor AMNT (aminomorpholine naphthalimide) that accurately localizes lysosomes in cells for imaging of cellular endogenous FA. The fluorescence emission peak of AMNT was at ∼540 nm, with a slight blue shift (∼528 nm) in response to FA, while the green fluorescence intensity increased. The probe exhibits excellent selectivity for FA among other biological interference species and a fast response time for FA. It is worth mentioning that the probe successfully imaged endogenous FA in cells in two-photon mode, making the probe an effective research tool in the biomedical field to study diseases related to abnormal FA expression.

A turn-on two-photon lysosome-targeted probe based on the ICT mechanism has been synthesized and was successfully used not only to monitor and image formaldehyde exogenously but also endogenously with excellent performance in living cells.     

Modification of carbon felt anodes using double-oxidant HNO3/H2O2 for application in microbial fuel cells

Carbon felt is widely used as an anode material in microbial fuel cells (MFCs) because of its high specific surface area, low cost, good electrical conductivity, and biocompatibility. In this paper, carbon felt samples were thermally treated with a mixed solution of concentrated HNO₃ and 30% H₂O₂ with different volume ratios of 1 : 3 (MFC-1), 1 : 1 (MFC-2), and 3 : 1 (MFC-3). The electrochemical performance of the resulting MFCs were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, chronoamperometry and polarization curve measurement. Fourier transform infrared spectroscopy and scanning electron microscopy were conducted to characterize the functional groups and the morphology of the carbon felts. After modification, the number of oxygen-containing functional groups in MFC-1, MFC-2, and MFC-3 increased compared with MFC-4 (bare anode MFC), the start-up time of the obtained MFCs was markedly shortened, and the charge transfer resistance of the bioanode was decreased. In MFC-2, the maximum power density was 758.2 mW m⁻², which was 51.1% higher than MFC-4. Increases of oxygen-containing functional groups on the modified anodes favored the adsorption and growth of bacteria and acceleration of electron transport between the electrode and bacteria. Thus, the electrochemical characteristics of MFCs employing these anodes were improved.

Carbon felt is widely used as an anode material in microbial fuel cells (MFCs) because of its high specific surface area, low cost, good electrical conductivity, and biocompatibility.     

A novel biocompatible zwitterionic polyurethane with AIE effect for cell imaging in living cells

In this work, a novel and stable zwitterionic polymer (TPE-CB PUs) was prepared to realize a cellular imaging system. TPE was conjugated into the backbone of zwitterionic polyurethane, which could be well dispersed in aqueous solution and emitted strong blue fluorescence because the TPE segment was aggregated in the core of TPE-CB PUs micelles. More importantly, the TPE-CB PUs micelles showed significant stability in a large pH window and with different storage times. In addition, the micelles exhibited low cytotoxicity in HeLa cells and mainly distributed in the cytoplasm after being incubated with cells. The outstanding properties of TPE-CB PUs combining the merits of AIE and a zwitterionic segment highlight its potential for use as a cell imaging material with remarkable capability.

In this work, a novel and stable zwitterionic polymer (TPE-CB PUs) was prepared to realize a cellular imaging system.     

A nano-sized Cu-MOF with high peroxidase-like activity and its potential application in colorimetric detection of H2O2 and glucose

Peroxidase widely exists in nature and can be applied for the diagnosis and detection of H₂O₂, glucose, ascorbic acid and other aspects. However, the natural peroxidase has low stability and its catalytic efficiency is easily affected by external conditions. In this work, a copper-based metal–organic framework (Cu-MOF) was prepared by hydrothermal method, and characterized by means of XRD, SEM, FT-IR and EDS. The synthesized Cu-MOF material showed high peroxidase-like activity and could be utilized to catalyze the oxidation of o-phenylenediamine (OPDA) and 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂. The steady-state kinetics experiments of the oxidation of OPDA and TMB catalyzed by Cu-MOF were performed, and the kinetic parameters were obtained by linear least-squares fitting to Lineweaver–Burk plot. The results indicated that the affinity of Cu-MOF towards TMB and OPDA was close to that of the natural horseradish peroxidase (HRP). The as-prepared Cu-MOF can be applied for colorimetric detection of H₂O₂ and glucose with wide linear ranges of 5 to 300 μM and 50 to 500 μM for H₂O₂ and glucose, respectively. Furthermore, the specificity of detection of glucose was compared with other sugar species interference such as sucrose, lactose and maltose. In addition, the detection of ascorbic acid and sodium thiosulfate was also performed upon the inhibition of TMB oxidation. Based on the high catalytic activity, affinity and wide linear range, the as-prepared Cu-MOF may be used for artificial enzyme mimics in the fields of catalysis, biosensors, medicines and food industry.

A Cu-MOF with high peroxidase-like activity was prepared and could be used for colorimetric detection of H₂O₂ and glucose with high selectivity and good linear range (50–500 μM).     

A fast chemiluminescent method for H(2)O(2) measurement in exhaled breath condensate

Background: Breath condensate can give useful information on volatile compounds produced at alveolar level. Actual concentration of H₂O₂ in breath condensate is dependent on its production at alveolar level and on the efficacy of the detoxifying systems, catalase, glutathione peroxidase, etc. Methods: In the present paper, a simple chemiluminescent method for the determination of the H₂O₂ collected in exhaled breath is shown and data of both smokers and nonsmokers volunteers are presented. Results: The chemiluminescent response is linear up to 100 μmol/l H₂O₂. The analytical sensitivity is about 0.01 μmol/l. Most of the nonsmokers have a H₂O₂ content lower than 0.05 μmol/l, while smokers have a content ranging from 0.1 to 0.6 μmol/l.     

Evaluation of an enzyme immunoassay system for measuring herpes simplex virus (HSV) type 1-specific and HSV type 2-specific IgG antibodies

MRL Diagnostics has developed a dual enzyme immunoassay (EIA) system that employs the recombinant Herpes Simplex Virus (HSV) type-specific glycoproteins G1 (HSV1) and G2 (HSV2) to detect HSV type-specific IgG antibodies. This system was evaluated using 155 consecutive sera previously tested in a conventional dual EIA system (Zeus) that employs multiple HSV1 and HSV2 proteins to detect type-common as well as type-specific antibodies. Sera were also analyzed by Western blot to determine the true HSV type-specific IgG reactivity pattern. Of 110 sera giving concordant reactivity patterns in the MRL and Zeus EIA systems, 108 (98%) also displayed concordant Western blot patterns; two sera gave false positive HSV2 reactivity in both EIA systems. Of 45 sera giving discordant MRL and Zeus EIA reactivity patterns, 41 (91%) displayed a Western blot reactivity pattern that matched the MRL reactivity pattern. Both the HSV1 IgG component and the HSV2 IgG component of the MRL EIA system were 100% sensitive and > 95% specific. In contrast, the Zeus HSV1 IgG EIA was 98% sensitive and 79% specific, and the Zeus HSV2 IgG EIA was 85% sensitive and 79% specific. An analysis of the distribution of index values in the MRL EIA system showed that low-positive values (1.0-3.0) were rare, but, when detected, often represented false positive results; only 11 MRL low-positive results were observed, but all 6 MRL false positive results were found within this low-positive subgroup. These findings show that the MRL dual EIA system effectively detects HSV type-specific IgG antibodies.