High Spatiotemporal Resolution Observation of Glutathione Hydropersulfides in Living Cells and Tissue via a Two-Photon Ratiometric Fluorescent Probe.

Glutathione hydropersulfides (GSSH) are alluded to play crucial roles in signal transduction, redox homeostasis, and metabolic regulation. However, the detailed biological functions of GSSH in these aspects are extremely ambiguous. The key barrier to understand the role of GSSH in biological systems is a lack of detection tools with high spatiotemporal resolution.

Sequential Detection of Superoxide Anion and Hydrogen Polysulfides under Hypoxic Stress via a Spectral-Response-Separated Fluorescent Probe Functioned with a Nitrobenzene Derivative.

Chronic hypoxic stress disrupts the intracellular redox homeostasis, leads to a series of physiological dysfunction, and finally results in many diseases including cancer and inflammatory and cardiovascular diseases. The intracellular redox status is related to the homeostasis between reactive oxygen species (ROS) and cellular antioxidant species. Superoxide anion (O) is considered to be a precursor of ROS.

Field-amplified sample injection combined with capillary electrophoresis for the simultaneous determination of five chlorophenols in water samples.

A sensitive method of CZE-ultraviolet (UV) detection based on the on-line preconcentration strategy of field-amplified sample injection (FASI) was developed for the simultaneous determination of five kinds of chlorophenols (CPs) namely 4-chlorophenol (4-CP), 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and 2,6-dichlorophenol (2,6-DCP) in water samples. Several parameters affecting CZE and FASI conditions were systematically investigated. Under the optimal conditions, sensitivity enhancement factors for 4-CP, 2-CP, 2,4-DCP, 2,4,6-TCP, and 2,6-DCP were 9, 27, 35, 43, and 43 folds, respectively, compared with the direct CZE, and the baseline separation was achieved within 5 min.

Ternary Emission of a Blue-, Green-, and Red-Based Molecular Imprinting Fluorescence Sensor for the Multiplexed and Visual Detection of Bovine Hemoglobin.

A novel ternary-emission fluorescence sensor was proposed by post-imprinting mixing blue-/green-/red-emission bovine hemoglobin (BHb) imprinted polymers (b-MIPs, g-MIPs, and r-MIPs) at a proper ratio and realized the multiplexed and visual detection of BHb. The three MIPs were individually embedded with blue-emission 7-hydroxycoumarin, green-emission CdTe quantum dots (QDs), and red-emission CdTe/ZnS QDs. Upon interaction with BHb within 8 min, the fluorescence of CdTe and CdTe/ZnS QDs were simultaneously turned off, whereas the 7-hydroxycoumarin turned on the fluorescence intensity.

Dispersive liquid-liquid microextraction coupled with pressure-assisted electrokinetic injection for simultaneous enrichment of seven phenolic compounds in water samples followed by determination using capillary electrophoresis.

Offline dispersive liquid-liquid microextraction combined with online pressure-assisted electrokinetic injection was developed to simultaneously enrich seven phenolic compounds in water samples, followed by determination using capillary electrophoresis, namely phenol, 4-chlorophenol, pentachlorophenol, 2,4,6-trichlorophenol, 2,4-dichlorophenol, 2-chlorophenol, and 2,6-dichlorophenol. Several parameters affecting separation performance of capillary electrophoresis and the enrichment efficiency of pressure-assisted electrokinetic injection and dispersive liquid-liquid microextraction were systematically investigated. Under the optimal conditions, seven phenolic compounds were completely separated within 14 min and good enrichment factors were obtained of 61, 236, 3705, 3288, 920, 86, and 1807 for phenol, 4-chlorophenol, pentachlorophenol, 2,4,6-trichlorophenol, 2,4-dichlorophenol, 2-chlorophenol, and 2,6-dichlorophenol, respectively.

A near-infrared fluorescent probe for evaluating endogenous hydrogen peroxide during ischemia/reperfusion injury.

Hydrogen peroxide (H2O2), as a major component of reactive oxygen species (ROS), plays an important role in normal physiological processes. A H2O2 burst also occurs in the ischemia/reperfusion (I/R) process and causes a series of physiological and pathological injuries. Therefore, it is important to determine concentration fluctuations of H2O2.

Polystyrene Encapsulated SERS Tags as Promising Standard Tools: Simple and Universal in Synthesis; Highly Sensitive and Ultrastable for Bioimaging.

Surface coating determined the sensitivity and stability of surface-enhanced Raman scattering (SERS) tags in bioanalysis. The reported various coatings suffered from the drawbacks of a lack of rigidity, stability, or synthesis versatility. Herein, we demonstrated robust polystyrene (PS) coated SERS tags that could be prepared by an easy and universal approach.

Evaluation of Glutathione S-Transferase Inhibition Effects on Idiopathic Pulmonary Fibrosis Therapy with a Near-Infrared Fluorescent Probe in Cell and Mice Models.

Idiopathic pulmonary fibrosis (IPF) is a lung-limited and progressive fibrotic disease. The early diagnosis and therapies of IPF are still full of clinical challenges. Glutathione S-transferase (GSTs) plays significant roles in promoting the formation of pulmonary fibrosis.

Self-assembly of nanoparticles by human serum albumin and photosensitizer for targeted near-infrared emission fluorescence imaging and effective phototherapy of cancer.

Photodynamic therapy (PDT) and photothermal therapy (PTT) are effective cancer treatments, and photosensitizers play the most important role in the treatment. However, photosensitizers are insufficient for in vivo tumor treatment. Herein, we develop a small molecule fluorophore Cy-HPT as a novel photosensitizer, which possesses the advantages of near-infrared (NIR) emission, high photothermal conversion efficiency and high singlet oxygen generation efficiency.

Preparation of a stoichiometric molecularly imprinted polymer for auramine O and application in solid-phase extraction.

We describe a stoichiometric approach to the synthesis of molecularly imprinted polymers specific for auramine O. Using the stoichiometric interaction in molecular imprinting, no excess of binding sites is necessary and binding sites are only located inside the imprinted cavities. The free base of the template was obtained to facilitate the interaction with the monomers.

Donor Characteristics, Recipient Outcomes, and Histologic Findings of Kidney Allografts With Diffuse Donor-derived Glomerular Fibrin Thrombi.

Background: Limited data are available on whether donor kidneys with diffuse glomerular fibrin thrombi (GFT) are safe to use. In this study, the clinicopathologic characteristics of allografts with diffuse donor-derived GFT were examined.

Methods: All deceased donor kidney transplant implantation biopsies from our institution between July 2011 and February 2018 with diffuse GFT were included.

Green multi-functional monomer based ion imprinted polymers for selective removal of copper ions from aqueous solution.

Green ion imprinted polymers (IIPs) were prepared in aqueous phase via the synergy of three functional monomers of low-cost eco-friendly gelatin (G), 8-hydroxyquinoline (HQ) and chitosan (C), namely G-HQ-C IIPs, and were applied as an effective and recyclable adsorbent to remove Cu(II) from aqueous solution. The as-prepared G-HQ-C IIPs were systematically characterized, and several major factors affecting adsorption capacity including solution pH, temperature and contact time were investigated in detail. The adsorption of Cu(II) on G-HQ-C IIPs followed the pseudo-second-order kinetic and Langmuir isotherm models, and the adsorption capacity increased with temperature increase.

A graphene oxide/gold nanoparticle-based amplification method for SERS immunoassay of cardiac troponin I.

Cardiac troponin I (cTnI) was considered as the "gold standard" for acute myocardial infarction (AMI) diagnosis owing to its superior cardiac specificity for cardiac damage and showing little or no changes in patients with a skeletal muscle disease or trauma. Herein, a new signal amplification surface-enhanced Raman scattering (SERS) platform was developed for recognition and detection of cTnI by using gold nanoparticles (AuNPs), graphene oxide (GO) and magnetic beads (MB). Here, antibody/Raman reporter labeled AuNP-functionalized GO were employed as both SERS nanotags and signal amplification carriers.

SERS-based droplet microfluidics for high-throughput gradient analysis.

In the last two decades, microfluidic technology has emerged as a highly efficient tool for the study of various chemical and biological reactions. Recently, we reported that high-throughput detection of various concentrations of a reagent is possible using a continuous gradient microfluidic channel combined with a surface-enhanced Raman scattering (SERS) detection platform. In this continuous flow regime, however, the deposition of nanoparticle aggregates on channel surfaces induces the "memory effect," affecting both sensitivity and reproducibility.

Imaging of anti-inflammatory effects of HNO via a near-infrared fluorescent probe in cells and in rat gouty arthritis model.

Nitroxyl (HNO) plays a crucial role in anti-inflammatory effects via the inhibition of inflammatory pathways, but the details of the endogenous generation of HNO still remain challenging owing to the complex biosynthetic pathways, in which the interaction between HS and NO simultaneously generates HNO and polysulfides (HS) in mitochondria. Moreover, nearly all the available fluorescent probes for HNO are utilized for imaging HNO in cells and tissues, instead of the in situ real-time detection of the simultaneous formation of HNO and HS in mitochondria and animals. Here, we have developed a mitochondria-targeting near-infrared fluorescent probe, namely, Mito-JN, to detect the generation of HNO in cells and a rat model.

Dummy molecularly imprinted polymers based on a green synthesis strategy for magnetic solid-phase extraction of acrylamide in food samples.

In this work, novel dummy molecularly imprinted polymers (DMIP) with propanamide as a dummy template molecule were prepared based on a green synthesis strategy of less consumption of hazardous/organic reagents and at mild conditions for magnetic solid-phase extraction (MSPE) of acrylamide in biscuit samples, followed by high performance liquid chromatography (HPLC) determination. The resultant DMIP was well characterized by FT-IR, SEM, TEM and VSM, exhibiting uniform nanoscale coreshell structure and good magnetic property in favor of simple rapid separation. Several main variables influencing MSPE efficiency were investigated, including DMIP dosage, sample solution pH, extraction time and desorption solvent; central composite design (CCD) and response surface methodology (RSM) were employed to assist in the MSPE condition optimization with rapidity and reliability.

Chemical Redox-Cycling for Improving the Sensitivity of Colorimetric Enzyme-Linked Immunosorbent Assay.

Herein, a redox-cycling was proposed to amplify the signal of enzyme-linked immunosorbent assay (ELISA), which was performed in a polystyrene microplate based on a classic sandwich-type. After the sandwich immunoreactions were finished, the alkaline phosphatase captured on a microplate triggered the hydrolyzation of l-ascorbic acid 2-phosphate to generate ascorbic acid (AA), which then reduced colorless tris(bathophenanthroline) iron(III) (Fe(BPT)) encapsulated in the micelle of TX-100 to pink red tris(bathophenanthroline) iron(II) (Fe(BPT)). In the presence of tris(2-carboxyethyl)phosphine, the oxidation product, dehydroascorbic acid, was transformed to AA quickly which then reduced Fe(BPT) again and again, resulting in the generation of abundant Fe(BPT) that could be read out conveniently by a commercial microplate reader or the naked eye.

Dual-template molecularly imprinted polymers for dispersive solid-phase extraction of fluoroquinolones in water samples coupled with high performance liquid chromatography.

Novel dual-template molecularly imprinted polymers (dt-MIPs) were prepared by simple and facile precipitation polymerization using norfloxacin (NOR) and enrofloxacin (ENR) as templates for simultaneous selective recognition and extraction of the two fluoroquinolones (FQs). The as-prepared dt-MIPs exhibited high adsorption capacity and excellent selectivity towards NOR and ENR. Several main parameters affecting the efficiency of dt-MIP based dispersive solid-phase extraction (DSPE) were systematically investigated, coupled with high performance liquid chromatography determination.

Imaging of intracellular sulfane sulfur expression changes under hypoxic stress via a selenium-containing near-infrared fluorescent probe.

Hypoxia is a significant global issue affecting the health of organisms. Oxygen homeostasis is critical for mammalian cell survival and cellular activities. Hypoxic stress can lead to cell injury and death, which contributes to many diseases.

Identification of Enantiomeric Byproducts During Microalgae-Mediated Transformation of Metoprolol by MS/MS Spectrum Based Networking.

Metoprolol (MPL) is a chiral β-blocker ubiquitously detected in various environments due to its low to moderate removal in wastewater treatment plants. This study was conducted to test the potential of using microalgae to degrade emerging contaminant MPL and to characterize the enantiomeric enrichment during MPL degradation by microalgae. The results showed that PO- P, NO- N and MPL could be simultaneously removed in the synthetic effluent by the targeted microalgae species, indicating microalgae were promising in wastewater treatment.

Preparation of stoichiometric molecularly imprinted polymer coatings on magnetic particles for the selective extraction of auramine O from water.

A novel magnetic molecularly imprinted polymer for the selective recognition of auramine O was rationally designed via screening from a library of nonimprinted polymers. A stoichiometric ratio of functional monomer (itaconic acid) and template molecule (auramine O) was found to be 1.5.

Rotational Paper-Based Microfluidic-Chip Device for Multiplexed and Simultaneous Fluorescence Detection of Phenolic Pollutants Based on a Molecular-Imprinting Technique.

In this study, we first present rotational paper-based microfluidic chips (RPADs) combined with a molecular-imprinting (MIP) technique to detect phenolic pollutants. The proposed rotational paper-based microfluidic chips could implement qualitative and quantitative analysis of two different phenolic contaminants, 4-nitrophenol (4-NP) and 2,4,6-trinitrophenol (TNP), simultaneously. Qualitative and quantitative analysis could be implemented simultaneously through fluorescence-intensity changes depending on the structures of quantum dots combined with a molecular-imprinting technique.

Functional ZnS:Mn(II) quantum dot modified with L-cysteine and 6-mercaptonicotinic acid as a fluorometric probe for copper(II).

Manganese-doped ZnS quantum dots (ZnS:Mn(II) QDs) were synthesized and modified with L-cysteine (L-Cys) and 6-mercaptonicotinic acid (MNA). This prevents the aggregation of the QDs and makes them available for the interaction with Cu(II) ions via Cu(II)-S interaction. As a result, the fluorescence of the QDs is quenched by Cu(II) due to an electron transfer mechanism.

Cytokine Clearances in Critically Ill Patients on Continuous Renal Replacement Therapy.

Background/aims: We sought to quantify any differences in cytokine clearance between continuous venovenous hemofiltration (CVVH-convective) compared to continuous venovenous hemodialysis (CVVHD-diffusive).

Methods: We conducted a 20 patient, multicenter, prospective, open-label randomized trial (CVVH or CVVHD) at continuous renal -replacement therapy (CRRT) initiation. Blood, urine, and effluent were collected at 0, 4, 24, and 48 h after initiation of CRRT.

Simple Way To Fabricate Novel Paper-Based Valves Using Plastic Comb Binding Spines.

A novel strategy for fabricating the paper-based valves on microfluidic paper-based analytical devices (μPADs) was described to control fluid in a user-friendly way. Initial prototypes of 3D μPADs manipulate the spatial distribution of fluid within the device. The movable paper channel in a different layer could be achieved using the channel's connection or disconnection to realize the valve function using plastic comb binding spines (PCBS).