Evaluation of the Efficacy and Safety of Tenofovir Disoproxil Fumarate in Intercepting Mother-to-Child Transmission of Hepatitis B Virus.

Vertical transmission of hepatitis B virus (HBV), especially in Asia, is a key target in the global elimination of HBV. This study assessed the effects of tenofovir disoproxil fumarate (TDF) in pregnant women for mother-to-infant transmission of HBV. A total of 122 pregnant women at our hospital met the inclusion criteria for high HBV DNA viral loads.

Single-holed cobalt - nitrogen - carbon hollow structure with oxidase-mimicking activity for the chemiluminescence determination of β - galactosidase activity.

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 into reactive oxygen species (ROS), giving a remarkable enhancement on the chemiluminescence (CL) signal of luminol - O reaction. The Co - N - C oxidase mimic has further been exploited in the biosensing field by the determination of the activity of β - galactosidase (β - gal).

Substrate-free fluorescence ratiometric detection of serum acetylcholinesterase activity with a self-assembled CsPbBr perovskite nanocrystals/tetraphenylporphyrin tetrasulfonic acid nanocomposite.

A dual-emission fluorescent nanoprobe was successfully constructed through self-assembling CsPbBr perovskite nanocrystals (CsPbBr PNCs) and tetraphenylporphyrin tetrasulfonic acid (TPPS). Acetylcholinesterase (AChE) is observed to directly quench the green fluorescence of CsPbBr PNCs at 520 nm in the absence of an enzyme substrate, but has no significant influence on the red emission of TPPS at 650 nm. The decreased value of the fluorescence intensities ratio at 520 to 650 nm (ΔF/F) is proportional to the logarithmic value of AChE activity ranging from 0.

Green-emission nitrogen-doped carbon quantum dots from alkaline N-methyl-2-pyrrolidinone for determination of β-galactosidase and its inhibitors.

A new fluorescence method was established for sensitive detection of β-galactosidase (β-gal) activity in spiked human serum and screening of inhibitor. Nitrogen-doped carbon quantum dots (N-CQDs) were prepared by solvothermal polymerization of N-methyl-2-pyrrolidinone in an alkaline condition. The colloidal N-CQDs exhibit good water solubility, stability, and emit bright green fluorescence with a maximum emission peak at 528 nm upon excitation at 420 nm.

A novel luminol chemiluminescence system induced by black phosphorus quantum dots for cobalt (II) detection.

Black phosphorus quantum dots (BP QDs) were prepared through a solvothermal exfoliation method in alkaline N-methyl-2-pyrrolidinone. The BP QDs induce distinct chemiluminescence (CL) of alkaline luminol directly. A possible reaction mechanism is proposed by the study of CL spectrum, ultraviolet-visible absorption spectra, electron paramagnetic resonance spectra as well as radical scavenging experiments.

Aptamer biorecognition-triggered hairpin switch and nicking enzyme assisted signal amplification for ultrasensitive colorimetric bioassay of kanamycin in milk.

A colorimetric aptasensing strategy for detection of kanamycin was designed based on aptamer biorecognition and signal amplification assisted by nicking enzyme. The aptamer of kanamycin was designed to be contained in the metastable state hairpin DNA. The target DNA as recycling DNA was located in the loop of hairpin DNA.

Light-accelerating oxidase-mimicking activity of black phosphorus quantum dots for colorimetric detection of acetylcholinesterase activity and inhibitor screening.

A feasible and sensitive colorimetric platform was established for the assay of acetylcholinesterase (AChE) activity and evaluation of its inhibitor screening, based upon the light-accelerating oxidase-mimicking activity of black phosphorus quantum dots (BP QDs). The BP QDs were synthesized through a thermal exfoliation method and characterized using various techniques. The BP QDs exhibit oxidase-mimicking catalytic activity on dissolved oxygen-mediating oxidation of 3,3',5,5'-tetramethylbenzidine, a typical substrate of oxidase.

Black phosphorus quantum dots are useful oxidase mimics for colorimetric determination of biothiols.

Black phosphorus quantum dots (BP QDs) with small size are synthesized using an easy to operate thermal method. It was found that BP QDs possess oxidase-mimicking activity. They can catalyze the oxidation of the substrate 3,3',5,5'-tetramethylbenzidine to produce a blue-colored product even in the absence of hydrogen peroxide.

Perovskite nanocrystals fluorescence nanosensor for ultrasensitive detection of trace melamine in dairy products by the manipulation of inner filter effect of gold nanoparticles.

Barium sulfate-coated CsPbBr perovskite nanocrystals (CsPbBr NCs@BaSO) was successfully synthesized that exhibited stable and intense fluorescence property in aqueous buffer. With the CsPbBr NCs@BaSO as signal readout, an ultrasensitive fluorescence nanosensor was developed for turn-on determination of melamine by the manipulation of inner filter effect of citrate-protected gold nanoparticles (AuNPs). The fluorescence of the CsPbBr NCs@BaSO was remarkably quenched by the AuNPs due to inner filter effect.

Luminescent metal organic frameworks-based chemiluminescence resonance energy transfer platform for turn-on detection of fluoride ion.

A luminescent metal organic frameworks (MOFs)-based chemiluminescence resonance energy transfer (CRET) platform was constructed for turn-on detection of fluoride ion. A hybrid MOFs was prepared by encapsulating strong fluorescence 2',7'-dichlorofluorescein (DCF) into the frames of NH-MIL-101(Al) MOFs, which led to a significant suppression of fluorescence signal of DCF. In the presence of fluoride ion, it destroyed the structure of the hybrid MOFs and released DCF molecules from the frames due to the formation of more stable aluminum hexafluoride complex ions [AlF] between fluoride ion and aluminum ion.

A fluorometric aptamer-based assay for ochratoxin A by using exonuclease III-assisted recycling amplification.

A fluorometric assay is described for ochratoxin A (OTA) using an aptamer. The method is based on exonuclease-assisted recycling amplification. The OTA-binding aptamer partially hybridizes with complementary DNA (cDNA) that is released when the aptamer recognizes OTA.

A covalent triazine framework as an oxidase mimetic in the luminol chemiluminescence system: application to the determination of the antioxidant rutin.

It is found that a covalent triazine framework (CTF-1) (that was prepared from 1,4-dicyanobenzene) exhibits oxidase-like activity toward the oxidation of luminol with dissolved oxygen in alkaline condition to produce intense blue chemiluminescence (CL). The reaction follows Michaelis-Menten kinetics and shows strong specificity for luminol. Reactive oxygen species including O, OH and O are testified to be involved in the reaction and responsible for the CL.

Ratiometric fluorometric determination of mercury(II) by exploiting its quenching effect on glutathione-stabilized and tetraphenylporphyrin modified gold nanoclusters.

A ratiometric fluorometric assay for mercury(II) ion is described. It is making use of glutathione-stabilized gold nanoclusters (GSH-AuNCs) modified with tetraphenylporphyrin tetrasulfonic acid (TPPS). The resultant GSH-AuNC/TPPS nanocomposite displays dual emission (at 572 and 664 nm) under a single excitation wavelength of 365 nm.

Bifunctional gold nanoclusters enable ratiometric fluorescence nanosensing of hydrogen peroxide and glucose.

The accurate quantification of hydrogen peroxide (HO) and glucose is essential significance in clinical diagnosis. Herein a selective and sensitive ratiometric fluorescent nanosensor was developed for the determination of HO and glucose by integrating peroxidase-like catalytic and fluorescent bifunctional properties of glutathione protected gold nanoclusters (GSH-AuNCs). The GSH-AuNCs exhibit inherent peroxidase-like activity and accelerate the decomposition of HO into hydroxyl radicals.

Fluorescein and its derivatives: New coreactants for luminol chemiluminescence reaction and its application for sensitive detection of cobalt ion.

Fluorescein and its derivatives, including 4',5'-dibromofluorescein, 2',7'-dichlorofluorescein and 2',4',5',7'-tetrabromofluorescein can be employed as efficient coreactants for luminol reaction. Under an alkaline condition they reacted with luminol to produce measureable chemiluminescence (CL) in the absence of any extra-oxidant. Cobalt ion (Co) significantly enhanced the CL emission of the reaction.

A novel electrochemiluminescence resonance energy transfer system of luminol-graphene quantum dot composite and its application in HO detection.

Luminol-nitrogen doped graphene quantum dot (luminol-NGQDs) nanocomposite was synthesized and a novel electrochemiluminescence resonance energy transfer (ECL-RET) process occurred between luminol as the donor and NGQDs as the acceptor in the composite. This ECL-RET effect helped luminol-NGQDs composite produced an anodic ECL signal without coreactants. The ECL-RET mechanism was also studied based on the fluorescence spectra, the ultraviolet-visible absorption spectra and the electrochemiluminescence (ECL) spectra.

Distance dependent fluorescence quenching and enhancement of gold nanoclusters by gold nanoparticles.

The interaction between fluorescent gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) has been investigated. It was observed that the fluorescence of AuNCs was remarkably quenched when direct contact with AuNPs. The fluorescence quenching of AuNCs by AuNPs was dynamic quenching and exhibited size-dependent property.

Label-free, turn-on fluorescent sensor for trypsin activity assay and inhibitor screening.

The development of new detection methods for proteases activity assay is important in clinical diagnostics and drug development. In this work, a simple, label-free, and turn-on fluorescent sensor was fabricated for trypsin, a protease produced in the pancreas. Cytochrome c, a natural substance of trypsin, could be selectively cleaved by trypsin into heme-peptide fragment.

Selective sensing of submicromolar iron(III) with 3,3',5,5'-tetramethylbenzidine as a chromogenic probe.

The development of highly selective and sensitive method for iron(III) detection is of great importance both from human health as well as environmental point of view. We herein reported a simple, selective and sensitive colorimetric method for the detection of Fe(III) at submicromolar level with 3,3,'5,5'-tetramethylbenzidine (TMB) as a chromogenic probe. It was observed that Fe(III) could directly oxidize TMB to form a blue solution without adding any extra oxidants.

A sensitive and label-free trypsin colorimetric sensor with cytochrome c as a substrate.

The development of simple and sensitive methods for protease sensing plays important roles in clinical diagnostics and drug development. Here a simple, rapid, label-free, and sensitive trypsin colorimetric sensor was developed by employing cytochrome c (cyt c) as an enzyme substrate and 3,3´,5,5´-tetramethylbenzidine (TMB) as a chromogenic reagent. It was found that cyt c hardly catalyzes H2O2-mediated TMB oxidation to produce a blue solution.

Gold nanoparticles-based chemiluminescence resonance energy transfer for ultrasensitive detection of melamine.

A turn-on chemiluminescence resonance energy transfer method was fabricated for the determination of melamine by using bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide-fluorescein chemiluminescence reaction as a donor and dispersed gold nanoparticles as an acceptor. The chemiluminescence signal of bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide-fluorescein reaction decreased significantly in the presence of dispersed gold nanoparticles because the absorption band of dispersed gold nanoparticles perfectly overlapped with the chemiluminescence spectrum. Melamine could induce the aggregation of gold nanoparticles, leading to a dramatic red-shift of the absorption band of dispersed gold nanoparticles.

A cost-efficient and portable sulfide device with in situ integrating gas-permeable porous tube isolation and long path absorbance detection.

A cost-efficient and portable device for detecting sulfide at submicromolar level was fabricated by in situ integrating gas-permeable porous tube isolation and long path absorbance detection. The device consisted of a pair of petri dish, having a diametrically strung porous membrane tube in the top cover. The ends of the tube were terminated by a light emitting diode and a photodiode via plugging acrylic optical fiber into the light input/output of tees.

A siphonage flow and thread-based low-cost platform enables quantitative and sensitive assays.

For pump-free, material abundant, portable, and easy-to-operate low-cost microfluidics, a siphonage flow microfluidic thread-based analytical device (S-μTAD) platform enabling quantitative and sensitive assays was designed. Renewable and continuous siphonage flow allowed replicate sampling and detection on one channel/device, obviating some possible inconsistencies among channels or devices. Y-shaped channels were fabricated with polyester cotton blend thread, due to its greater chemiluminescent sensitivity in comparison with that of cotton and polyester threads.

Prussian blue nanoparticles as peroxidase mimetics for sensitive colorimetric detection of hydrogen peroxide and glucose.

Prussian blue nanoparticles (PB NPs) exhibits an intrinsic peroxidase-like catalytic activity towards the hydrogen peroxide (H2O2)-mediated oxidation of classical peroxidase substrate 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt to produce a colored product. The catalysis follows Michaelis-Menen kinetics and shows strong affinity for H2O2. Using PB NPs as a peroxidase mimetics, a colorimetric method was developed for the detection of 0.

Chemiluminescence determination of trimetazidine via inducing the aggregation of gold nanoparticles.

A simple, rapid and sensitive chemiluminescence (CL) method combined with flow injection analysis was developed for the determination of trimetazidine. Trimetazidine was found to significantly increase the CL signal arising from N-bromosuccinimide-luminol reaction in the presence of gold nanoparticles. The enhanced CL intensity was proportional to trimetazidine concentration in the range of 0.