A simple fluorescence detection of acetylcholinesterase with peroxidase-like catalysis from iodide.

Acetylcholinesterase (AChE) is an important enzyme in the central and peripheral nervous system that regulates the balance of the neurotransmitter acetylcholine. In this work, a simple, selective and sensitive fluorescence assay was developed toward AChE activity. A conventional AChE substrate acetylthiocholine iodide (ATCI) was applied.

Simple and sensitive fluorescence detection of trypsin with Cu-Bovine serum albumin complex as a peroxidase mimic.

Trypsin is a serine protease playing a key role in regulating pancreatic exocrine function and can be applied as a marker for the diagnosis of pancreatitis. In this work, a convenient and sensitive fluorescent assay was developed toward trypsin. Hydrogen peroxide slowly oxidized a non-fluorescent o-phenylenediamine (OPD) into a fluorescent product 2,3-diaminophenothiazine (DAP) under the catalytic from copper ions.

Novel Electrochemiluminescent Immunosensor Using Dual Amplified Signals from a CoFe Prussian Blue Analogue and Au Nanoparticle for the Detection of Lp-PLA2.

Coronary heart disease (CHD) poses an important threat to human health, and its pathogenesis is the formation of atheromatous plaques in coronary ventricles. Compared to other biomarkers, lipoprotein-associated phospholipase A2 (Lp-PLA2), which is involved in multiple processes of atherosclerosis, is a noticeable inflammatory biomarker related to CHD. Herein, using a multifunctional nanocomposite containing a CoFe Prussian blue analogue (PBA) and Au nanoparticles (AuNPs) (AuNPs@CoFe PBA) as a sensing substrate, an electrochemiluminescent (ECL) immunosensor was developed for the highly sensitive detection of Lp-PLA2.

Colorimetric detections of iodide and mercuric ions based on a regulation of an Enzyme-Like activity from gold nanoclusters.

A simple colorimetric method was developed for sensitive and selective detections of I and Hg. Histidine stabilized gold nanoclusters (His-AuNCs) were synthesized and catalyzed the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to a blue product. As a strong ligand toward gold, iodide (I) attached to the surface of the His-AuNCs and significantly enhanced the oxidase-like activity of the His-AuNCs.

Ready-to-Use Colorimetric Platform for Versatile Enzyme Assays through Copper Ion-Mediated Catalysis.

A low cost and versatile colorimetric platform is developed for selective detections of various enzymes. Similar to peroxidases, free copper ion catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of HO and turns TMB into a blue product. Bindings from ligands toward copper ions inhibit this catalysis.

Sensitive detection of glutathione through inhibiting quenching of copper nanoclusters fluorescence.

A method for a sensitive fluorescence detection of glutathione was established. Glutathione-stabilized copper nanoclusters (CuNCs) were synthesized via a facile process. These CuNCs showed blue fluorescence with a peak around 450 nm.

Clinical effect of Chinese herbal medicine for removing blood stasis combined with acupuncture on sequelae of cerebral infarction.

Objective: To assess the clinical efficacy of Chinese herbal medicine for removing blood stasis combined with acupuncture in the treatment of sequelae of cerebral infarction.

Methods: Ninety patients with cerebral infarction admitted to our hospital from April 2018 to April 2020 were enrolled and equally allocated to an experimental group and a control group. The control group was treated with aspirin, and the experimental group was treated with Chinese herbal medicine for removing blood stasis combined with acupuncture.

Detection of silver through amplified quenching of fluorescence from polyvinyl pyrrolidone-stabilized copper nanoclusters.

Silver ion detection with ultra-high sensitivity was established. We synthesized copper nanoclusters (CuNCs) with blue fluorescence through a one-pot process. Instead of a direct quencher toward the CuNCs, silver ions activated the strong oxidation from persulfate and subsequently converted divalent manganese ion into manganese dioxide (MnO).

Turn-on fluorescence measurement of acid phosphatase activity through an aggregation-induced emission of thiolate-protected gold nanoclusters.

A fluorescence method was developed for a turn-on measurement of acid phosphatase (ACP) activity. It was found that cerous ion (Ce) could lead to an enhancement of glutathione protected gold nanocluster fluorescence through an aggregation-induced-emission (AIE) process, while its higher valent counterpart ceric ion (Ce) could not. In a weakly acidic environment, ACP catalyzed the dephosphorylation of a phosphate ester of ascorbic acid, with a generation of ascorbic acid (AA).

Determination of dopamine based on its enhancement of gold-silver nanocluster fluorescence.

Dopamine (DA) is one of the most important neurotransmitters in human bodies and its sensitive detection remains a challenge. Herein, protein stabilized gold-silver nanoclusters (Au-AgNCs) were synthesized at first. It was found that the introduction of dopamine lead to a significant enhancement of the fluorescence from the nanoclusters, together with a red-shift of the peak.

Fluorescence detections of hydrogen peroxide and glucose with polyethyleneimine-capped silver nanoclusters.

Detection of hydrogen peroxide is of significant importance for biological assays, and fluorescence methods are intensively reported for this purpose. Due to the highly oxidative property of this species, usually fluorescence quenching is obtained during the interactions and decreased signals are rendered. In this report, this oxidative property was adopted for an increased fluorescence signaling.

Sensitive detection of molybdenum through its catalysis and quenching of gold nanocluster fluorescence.

Molybdenum (Mo) is an essential nutrient for the proper functioning of some enzymes in living organisms as human beings. Conventional methods for its detection require complicated instrumentations as atomic absorption or mass spectrometers. In this work, a sensitive kinetic fluorescence was developed as an alternative.

An experimental study on the treatment of diabetes-induced cognitive disorder mice model with exosomes deriving from mesenchymal stem cells (MSCs).

The occurrence rate of senile dementia among diabetes patients is high, but there is still no effective therapeutic method. This study aimed to explore curative effect of exosomes deriving from MSCs treating diabetes-induced cognition impairment. After BM-MSCs culture was purified, Western Blot and electron microscope were used to identify exosomes which were injected into diabetes mouse through intracranial injection.

A C-reactive protein immunosensor based on platinum nanowire / titania nanotube composite sensitized electrochemiluminescence.

C-reactive protein (CRP) is one of the important indicators of inflammatory response. It plays as an essential role in diseases such as myocardial infarction and atherosclerosis. A simple and effective label-free electrochemiluminescent (ECL) immunosensor for quantitative detection of CRP is reported.

Fluorometric determination of nitrite through its catalytic effect on the oxidation of iodide and subsequent etching of gold nanoclusters by free iodine.

A method for sensitive detection of nitrite is presented. It is found that the red fluorescence of gold nanoclusters (with excitation/emission maxima at 365/635 nm) is quenched by traces of iodine via etching. Free iodide is formed by oxidation of iodide by bromate anion under the catalytic effect of nitrite.

Determination of alkaline phosphatase activity based on enzyme-triggered generation of a thiol and the fluorescence quenching of silver nanoclusters.

A fluorimetric method is described for the determination of alkaline phosphatase (ALP) activity. It is based on the use of polyethyleneimine-coated silver nanoclusters (AgNCs), which display an intense blue fluorescence peaking at 450 nm (under 375 nm excitation). ALP catalyzes the dephosphorylation of the thiophosphate amifostine to generate a thiol that binds to the AgNCs and causes its fluorescence to be quenched.

Fluorescence red-shift of gold-silver nanoclusters upon interaction with cysteine and its application.

In this work, gold-silver alloy nanoclusters (AuAg NCs) were demonstrated as a novel probe for fluorescent detection of cysteine (Cys). The alloy nanoclusters were fabricated by bovine serum albumin as a template and NaBH as a reducer. They showed a red emission at 650 nm.

A sensitive electrochemiluminescent biosensor based on AuNP-functionalized ITO for a label-free immunoassay of C-peptide.

The C-peptide is a co-product of pancreatic β-cells during insulin secretion; its content in body fluid is closely related to diabetes. This paper reports an immune-sensing strategy for a simple and effective assay of C-peptide based on label-free electrochemiluminescent (ECL) signaling, with high sensitivity and specificity. The basal electrode was constructed of an indium tin oxide (ITO) glass as a conductive substrate, which was decorated by Au nanoparticles (AuNPs) with hydrolysed (3-aminopropyl)trimethoxysilane as the linker.

Copper ion detection with improved sensitivity through catalytic quenching of gold nanocluster fluorescence.

In this report, a sensitive fluorescence detection of copper (Ⅱ) ion was developed. Although itself only a weak quencher toward gold nanocluster fluorescence, this ion functioned as a catalyst that accelerated the oxidation of iodide into iodine by a strong oxidant. The so-produced iodine quenched the nanocluster fluorescence through an efficient etching reaction, which rendered a much improved sensitivity for copper detection.

A label-free electrochemiluminescent immunosensor for glutamate decarboxylase antibody detection on AuNPs supporting interface.

In this paper, we will describe a novel lable-free electrochemiluminescent (ECL) immunosensor for the detection of glutamate decarboxylase antibody (GADA) in which Au nanoparticles (AuNPs) had pre-functionalized the indium tin oxide (ITO) glass to support the sensing interface. The preparation of the basal electrode only need a simple two-step drop coating, a thin polymer of hydrolyzed 3-aminopropyl trimethoxysilane, and the AuNPs gel on the ITO substrate. The AuNPs not only enhanced the ECL signal of luminol, but also acted to immobilize the glutamate decarboxylase (GAD) to build the sensing host.

Gold nanocluster-based ratiometric fluorescent probes for hydrogen peroxide and enzymatic sensing of uric acid.

A method is described for ratiometric fluorometric assays of HO by using two probes that have distinct response profiles. Under the catalytic action of ferrous ion, the 615 nm emission of protein-stabilized gold nanoclusters (under 365 nm photoexcitation) is quenched by HO, while an increased signal is generated with a peak at 450 nm by oxidizing coumarin with the HO/Fe(II) system to form a blue emitting fluorophore. These decrease/increase responses give a ratiometric signal.

A New Tactic for Label-Free Recognition of β-Trophin via Electrochemiluminescent Signalling on an AuNPs Supported Immuno-Interface.

In this paper, a new strategy is reported for preparing a label-free β-trophin electrochemiluminescent (ECL) immunosensor with good specificity, reproducibility and stability. An aquagel polymer from the hydrolysis of (3-aminopropyl) trimethoxysilane acted as the linker to catch the Au nanoparticles (AuNPs) on the indium-tin oxide (ITO) substrate by a two-step method. The AuNPs play an important role in enhancing ECL and immobilizing the β-trophin antibody.

A label-free genetic biosensor for diabetes based on AuNPs decorated ITO with electrochemiluminescent signaling.

The variation of I27L gene closely relates to increasing risk of type 2 diabetes, thus it is greatly significant to develop various methods for its identification or monitoring. We report here a novel label-free electrochemiluminescent (ECL) biosensor for simple and effective determination of I27L gene based on Au nanoparticles functionalized ITO electrode. The ECL technique is employed to monitor the hybridization of DNA strands by measuring the changes of its intensity.

A nanocluster-based fluorescent sensor for sensitive hemoglobin detection.

In this report, a fluorescence sensor for sensitive detection of hemoglobin was developed. Gold nanoclusters were first synthesized with bovine serum albumin. It was found that both hydrogen peroxide and hemoglobin could weakly quench the fluorescence from the gold nanoclusters, but when these two were applied onto the nanolcusters simultaneously, a much improved quenching was resulted.

Turn-on fluorescence detection of ascorbic acid with gold nanolcusters.

In this report, a sensitive fluorescent detection of ascorbic acid was developed with protein-stabilized gold nanoclusters. The fluorescence signal from the gold nanoclusters could be effectively quenched by elemental iodine. This kind of quenching could be inhibited by ascorbic acid through a corresponding reduction process, thus a turn-on response toward ascorbic acid was obtained.