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A chemiluminescence (CL) based assay is described for the determination of the environmental pollutant 2-hydroxyfluorene (2-HOFlu) which is found to inhibit the CL of a system composed of the G-quadruplex/hemin complex (a DNAzyme), H.sub.2O.sub.2, and luminol. The G-rich aptamer PW17 is transformed to a potassium(I)-stabilized G-quadruplex-hemin complex which displays peroxidase-like activity to catalyze the oxidation of luminol by H.sub.2O.sub.2 which is accompanied by strong blue CL emission. On addition of 2-HOFlu, it will participate in the G-quadruplex DNAzyme-mediated oxidation by H.sub.2O.sub.2. As a result, CL intensity is decreased. The difference in CL intensity ([DELTA]I) before and after addition of 2-HOFlu serves as the signal for its quantitation. In water of pH 9.0, a linear relationship is found for the 1 nM to 1 [mu]M concentration range, with a 0.2 nM detection limit. The assay is highly selective over other fluorene derivatives. It was successfully applied to the determination of 2-HOFlu in spiked lake water samples. The method is rapid, cost-effective and convenient. Conceivably, it has a wide scope in that it may be applied to other target pollutants for which G-quadruplexes are available.

A novel glow-type chemiluminescence (CL)-based nanosensing system was developed for sensitive and rapid point-of-care testing (POCT) of H.sub.2O.sub.2 in food. CuSe nanoparticles (CuSe.sub.NPs) have excellent peroxidase-like activity. After being modified with thiols of 4-mercaptophenylboronic acid (MBA) (CuSe.sub.NPs@MBA), luminol can be catalyzed to produce long-lasting CL in the presence of H.sub.2O.sub.2. The possible reason for the long-lasting glow-type CL behavior was explored. Under the optimized condition, H.sub.2O.sub.2 can be sensitively detected with improved repeatability. The limit of detection is as low as 0.30 M. To meet the requirement of in situ and outside of laboratory detection, a 3D-printed portable device was designed which can eliminate the environmental interference to improve detection accuracy. The developed multifunctional platform also has the advantages of simple operation and low cost, suggesting its great potential for applications in food and agricultural fields. Graphical

A single-holed cobalt - nitrogen - carbon (Co - N - C) hollow structure nanozyme has been fabricated by in situ growth of zeolitic imidazolate framework (ZIF - 67) on the polystyrene (PS) sphere and following treatment by high-temperature carbonization. The Co - N - C nanostructure mimics the activity of oxidase and can activate O.sub.2 into reactive oxygen species (ROS), giving a remarkable enhancement on the chemiluminescence (CL) signal of luminol - O.sub.2 reaction. The Co - N - C oxidase mimic has further been exploited in the biosensing field by the determination of the activity of - galactosidase ( - gal). The CL method for - gal activity has a linear range of 0.5 mU·L.sup.-1 to 5.0 U·L.sup.-1, a detection limit of 0.167 mU·L.sup.-1, and the precision of 3.1% (5.0 U·L.sup.-1, n = 11). This method has been employed to assess inhibitor screening of - gal and determine activity of - gal in spiked human serum samples. Graphical

Purposes: To explore the optimization method and application of Au-NP-enhanced luminol––H2O2 luminescence system in TORCH (TOX, RV, CMV, HSVI, and HSVII) detection. Method: 4.5 × 10−5 mmol/L gold nano solution was prepared with chloroauric acid as the reducing agent and trisodium citrate as the stabilizer. After curing for 3 days, Au NPs participate in the luminal–H2O2 luminescence system to detect TORCH antibodies and establish the cut off value. SPSS 18.0 software was used to analyze the TORCH antibodies detected by the nano-gold-enhanced luminol luminescence method and TORCH kit. Additionally, its detection performance is studied. Results: The results of a paired t-test for the absorbance values of samples with and without gold nanoparticles showed that there were statistically significant differences (p < 0.001) between the two methods in the detection of TOX, RV, CMV, HSVI, and HSVII. The luminescence values with the addition of gold nanoparticles were significantly higher than those without gold nanoparticles. Using the Au NP–luminol–H2O2 chemiluminescence method, 127 serum samples were tested for TORCH antibodies. The sensitivities were 84.6%, 83.3%, 90.9%, 85.7%, and 84.6%, while the specificities were 94.7%, 96.5%, 96.6%, 97.3%, and 95.6%, respectively. The sensitivity and specificity of the chemiluminescence method enhanced by gold nanoparticles are significantly improved compared to the chemiluminescence method without enhancers. Conclusions: Au NPs participate in the luminal–H2O2 luminescent system. The absorbance, sensitivity, and specificity of TORCH antibodies show that Au NPs can enhance the luminol–H2O2 luminescent system. Au NP–luminol–H2O2 luminescence system has broad application prospects in the detection of eugenics.

A dual signal-amplified sandwich electrochemiluminescence (ECL) immunosensor was fabricated for trace detection of procalcitonin (PCT). CeO.sub.2-Au@Pt composed of sea urchin-like Au@Pt nanoparticles coated on CeO.sub.2 hollow nanospheres was immobilized on electrode surface to electrochemically catalyze H.sub.2O.sub.2 to produce a large number of superoxide anion (O.sub.2.sup.*-). The immunosensor was prepared by linking the capture antibody on immobilized CeO.sub.2-Au@Pt with heptapeptide (HWRGWVC), which could maintain the activity of the antibody. The prepared Au star@BSA was used to bind abundant luminol for labeling the secondary antibody (Ab.sub.2). Upon the sandwich-typed immunoreactions, the O.sub.2.sup.*- could react with the introduced luminol on the immunosensor surface to produce strong ECL intensity. With an outstanding linear detection range and a low detection limit of 17 fg/mL, the ECL immunosensor permitted ultrasensitive detection of PCT at a low H.sub.2O.sub.2 concentration and demonstrated its high application potential in the clinical assay. Graphical abstract

Water-soluble forms of α-tocopherol (TP) as an effective antioxidant were obtained by encapsulating it into nanoparticles (NPs) of amphiphilic copolymers of N-vinylpyrrolidone with triethylene glycol dimethacrylate (CPL1-TP) and N-vinylpyrrolidone with hexyl methacrylate and triethylene glycol dimethacrylate (CPL2-TP) synthesized by radical copolymerization in toluene. The hydrodynamic radii of NPs loaded with TP (3.7 wt% per copolymers) were typically ca. 50 or 80 nm depending on copolymer composition, media, and temperature. Characterization of NPs was accomplished by transmission electron microscopy (TEM), IR-, and [sup.1]H NMR spectroscopy. Quantum chemical modeling showed that TP molecules are capable to form hydrogen bonds with donor groups of the copolymer units. High antioxidant activity of both obtained forms of TP has been found by the thiobarbituric acid reactive species and chemiluminescence assays. CPL1-TP and CPL2-TP effectively inhibited the process of spontaneous lipid peroxidation as well as α-tocopherol itself. The IC[sub.50] values of luminol chemiluminescence inhibition were determined. Antiglycation activity against vesperlysine and pentosidine-like AGEs of TP water-soluble forms was shown. The developed NPs of TP are promising as materials with antioxidant and antiglycation activity and can be used in various biomedical applications.

Chemiluminescence (CL) is regarded as a better method for the detection of reactive oxygen species (ROS). However, the weak CL intensity prevents its further application. Many nanomaterials have been developed to enhance CL intensity, and mixed-ligand MOFs incorporating additional metals or organic ligands exhibit high efficiency in catalyzing. In this work, one kind of bimetallic mixed-ligand metal–organic framework (Ni-Co m-MOF) was synthesized using solvothermal methods. The material was morphologically characterized and demonstrated to be a dense and spherical flower-like structure. The addition of Ni-Co m-MOFs significantly enhanced the CL intensity of the luminol-H[sub.2]O[sub.2] system by nearly 2,000-fold. The enhancement was found through further research as hydrogen peroxide was catalyzed to create hydroxyl radicals, etc., which reacted more easily with luminol. Herein, significant enhancement of the CL system by Ni-Co m-MOFs was identified, which provides ideas for improving the sensitivity and signal-to-noise ratio development of CL detectors.

A highly sensitive molecularly imprinted electrochemiluminescence (MIECL) sensor was developed for detecting rifampicin (RIF) based on luminol@Co-MOF. Co-MOF had a significant enhancement of ECL signaling in the luminol-O 2 system. Molecular imprinted polymers (MIPs) with the introduction of RIF provide new properties for the specific recognition of RIF. A noteworthy decrease in ECL intensity was observed with higher concentrations of RIF. Consequently, the ECL signal was controlled by RIF elution from and adsorption by the MIP, thus establishing a new method for RIF detection. Under optimal conditions, this sensor exhibited linear detection ranges of RIF between 1.0 × 10 −11  mol L −1 and 1.0 × 10 −6  mol L −1 , with a detection limit of 3.3 × 10 −12  mol L −1 ( S / N  = 3). The recoveries ranged between 98.1 and 106.0% in fish samples. This method can be used as a sensitive and rapid method to detect RIF in real samples. Graphical Abstract

The monitoring of reactive oxygen species in living cells provides valuable information on cell function and performance. Lately, the development of chemiluminescence-based reactive oxygen species monitoring has gained increased attention due to the advantages posed by chemiluminescence, including its rapid measurement and high sensitivity. In this respect, specific organelle-targeting trackers with strong chemiluminescence performance are of high importance. We herein report the synthesis and chemiluminescence properties of eight novel phosphonium-functionalized amino-acylated luminol and isoluminol derivatives, designed as mitochondriotropic chemiluminescence reactive oxygen species trackers. Three different phosphonium cationic moieties were employed (phenyl, p-tolyl, and cyclohexyl), as well as two alkanoyl chains (hexanoyl and undecanoyl) as bridges/linkers. Synthesis is accomplished via the acylation of the corresponding phthalimides, as phthalhydrazide precursors, followed by hydrazinolysis. This method was chosen because the direct acylation of (iso)luminol was discouraging. The new derivatives’ chemiluminescence was evaluated and compared with that of the parent molecules. A relatively poor chemiluminescence performance was observed for all derivatives, with the isoluminol-based ones being the poorest. This result is mainly attributed to the low yield of the fluorescence species formation during the chemiluminescence oxidation reaction.

This critical review discusses the results published between 2000 and 2005 on the development of analytical systems based on the luminol chemiluminescent and electrochemiluminescent reactions. An increasing number of non-specific detection systems based on the enhancing, inhibiting or catalysing effect of a large range of compounds have been published. Possible detected compounds and their concomitant presence in samples are discussed. Chemiluminescent and electrochemiluminescent reactions were also found to merge in biochip and microarray development as a possible substitute to the well-established but hardly quantitative fluorescent detections.