A Catechol-Meter Based on Conventional Personal Glucose Meter for Portable Detection of Tyrosinase and Sodium Benzoate.

In this study, the personal glucose meter (PGM) was first used as a fast and user-friendly meter for analyzing catechol (CA) based on the reduction of the mediator K3[Fe(CN)6] to K4[Fe(CN)6] in the glucose test strip. Then, an easy, low-cost, and convenient PGM-based method for detecting tyrosinase (TYR) activity and sodium benzoate (SBA) was developed on the basis of the TYR-catalyzed reaction. In this method, CA is oxidized to form o-benzoquinone by TYR, thereby reducing the residual amount of CA and the PGM readout. On the other hand, SBA can inhibit the oxidation of CA catalyzed by TYR and increase the residual amount of CA after the enzymatic reaction. Therefore, the activity of TYR is proportional to the difference in the PGM readout of CA, and the concentration of SBA is positively correlated with the residual amount of CA. After the relevant experimental conditions were systematically optimized, the proposed PGM-based method for the detection of TYR and SBA was successfully validated. The liner ranges are 1.0-103.3 U/mL and 6.25-1000 ppm, and the quantification limits are 1.0 U/mL and 6.25 ppm for TYR and SBA, respectively. Moreover, the spiked recovery tests in normal human serum and carbonate beverages (i.e., Cola, Sprite, and Fanta) were performed, and the recoveries (91.6-106.8%) further confirm the applicability of the PGM-based method in real sample analysis.

Multicolor colorimetric assay for copper ion detection based on the etching of gold nanorods.

An effective, selective, and multicolor colorimetric assay for Cu2+ detection based on the regulation of peroxidase-like nanozyme-mediated etching of gold nanorods (Au NRs) is proposed. Cu2+-creatinine complex is selected as the nanozyme that exhibits excellent peroxidase-like activity even in the case of low concentration of Cu2+, which can catalyze 3,3,5,5-tetramethylbenzidine (TMB) to produce oxidized TMB (TMB+) in the presence of hydrogen peroxide, and TMB+ is oxidized to generate TMB2+ after adding H+, and the TMB2+ can etch Au NRs. The determination of Cu2+ is achieved based on the blue shift of the longitudinal localized surface plasmon resonance peak of Au NRs. Under the optimal conditions, the developed colorimetric assay exhibits high sensitivity for the detection of Cu2+ (limit of detection is 0.034 µM) with a wide linear range of 0.05-4.0 µM (R2 = 0.987). The solution shows a rainbow-like color in response to the increase of Cu2+ concentration, which can realize the semi-quantitative detection of Cu2+ by naked eyes. In addition, the developed method exhibits excellent selectivity for Cu2+-detection. The established method was used for the determination of Cu2+ in lake water, soil, and normal human serum with satisfactory recovery of spiked samples.

A Paper-Based Analytical Device Integrated with Smartphone: Fluorescent and Colorimetric Dual-Mode Detection of ß-Glucosidase Activity.

In this work, indoxyl-glucoside was used as the substrate to develop a cost-effective, paper-based analytical device for the fluorescent and colorimetric dual-mode detection of ß-glucosidase activity through a smartphone. The ß-glucosidase can hydrolyze the colorless substrate indoxyl-glucoside to release indoxyl, which will be self-oxidized to generate green products in the presence of oxygen. Meanwhile, the green products emit bright blue-green fluorescence under ultraviolet-visible light irradiation at 365 nm. Fluorescent or colorimetric images were obtained by a smartphone, and the red-green-blue channels were analyzed by the Adobe Photoshop to quantify the ß-glucosidase activity. Under the optimum conditions, the relative fluorescent and colorimetric signals have a good linear relationship with the activity of ß-glucosidase, in the range of 0.01-1.00 U/mL and 0.25-5.00 U/mL, and the limits of detection are 0.005 U/mL and 0.0668 U/mL, respectively. The activities of ß-glucosidase in a crude almond sample measured by the fluorescent and colorimetric methods were 23.62 ± 0.53 U/mL and 23.86 ± 0.25 U/mL, respectively. In addition, the spiked recoveries of normal human serum and crude almond samples were between 87.5% and 118.0%. In short, the paper-based device, combined with a smartphone, can provide a simple, environmentally friendly, and low-cost method for the fluorescent and colorimetric dual-mode detection of ß-glucosidase activity.

Preparation of Fe3O4@SW-MIL-101-NH2 for selective pre-concentration of chlorogenic acid metabolites in rat plasma, urine, and feces samples.

An innovative sandwich-structural Fe-based metal-organic framework magnetic material (Fe3O4@SW-MIL-101-NH2) was fabricated using a facile solvothermal method. The characteristic properties of the material were investigated by field emission scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction, vibrating sample magnetometry, and Brunauer-Emmett-Teller measurements. Fe3O4@SW-MIL-101-NH2 is associated with advantages, such as robust magnetic properties, high specific surface area, and satisfactory storage stability, as well as good selective recognition ability for chlorogenic acid (CA) and its metabolites via chelation, hydrogen bonding, and π-interaction. The results of the static adsorption experiment indicated that Fe3O4@SW-MIL-101-NH2 possessed a high adsorption capacity toward CA and its isomers, cryptochlorogenic acid (CCA) and neochlorogenic acid (NCA), and the adsorption behaviors were fitted using the Langmuir adsorption isotherm model. Then, a strategy using magnetic solid-phase extraction (MSPE) and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF MS/MS) was developed and successfully employed for the selective pre-concentration and rapid identification of CA metabolites in rat plasma, urine, and feces samples. This work presents a prospective strategy for the synthesis of magnetic adsorbents and the high-efficiency pretreatment of CA metabolites.

Investigation on the Peroxidase-like Activity of Vitamin B6 and Its Applications in Colorimetric Detection of Hydrogen Peroxide and Total Antioxidant Capacity Evaluation.

The peroxidase-like activity of vitamin B6 (VB6) was firstly demonstrated by catalyzing the peroxidase chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) at the existence of H2O2. The influence of different factors on the catalytic property of VB6, including pH, temperature, VB6 concentration, and incubation time, were investigated. The steady-state kinetic study results indicate that VB6 possesses higher affinity to H2O2 than natural horseradish peroxidase and some other peroxidase mimics. Besides, the radical quenching experiment results confirm that hydroxyl radical (•OH) accounts for the catalytic process. Based on the excellent peroxidase-like catalytic activity of VB6, the colorimetric methods for H2O2 and gallic acid (GA) detection were developed by measuring the absorbance variance of the catalytic system. Under the optimal conditions, the linear ranges of the methods for H2O2 and GA determination with good selectivity are 50.0-600.0 µM and 10.0-50.0 µM, respectively. In addition, the developed method was applied in the detection of H2O2 in milk samples and evaluation of total antioxidant capacity of different tea infusions. This study may broaden the application prospect of VB6 in environmental and biomedical analysis fields, contribute to profound insight of the physiological functions of VB6, as well as lay foundation for further excavation of small-molecule peroxidase mimics.

Highly sensitive visual colorimetric sensor for trichlorfon detection based on the inhibition of metallization of gold nanorods.

In this study, a highly sensitive visual colorimetric sensor was designed for the detection of trichlorfon based on inhibiting ascorbate oxidase (AAO)-induced metallization of gold nanorods (Au NRs). Ascorbic acid (AA) can reduce silver ion (Ag+) to metal silver (Ag) that will be deposited on the surface of Au NRs, which results in the blue shift of longitudinal localized surface plasmon resonance (LSPR) peak of Au NRs, accompanying by perceptible color changes from red to cyan to red to yellow. In the presence of trichlorfon, the activity of AAO will be inhibited, resulting in less AA is hydrolyzed to dehydroascorbic acid (DHA), and therefore more Ag+ is reduced to Ag by AA. Under the optimized conditions, detection of trichlorfon has a wide linear range of 27.8-11111.1 µg/L with a limit of detection as low as 132.6 ng/L. Moreover, the sensor has a good sample spiked recovery (84.7-96.8%) for the determination of trichlorfon in lake water samples. The proposed method can achieve rapid analysis (about 10 min) of trichlorfon with simple operation when there are no other types of organophosphorus pesticides in the real samples.

Preparation of Fe3O4@SW-MIL-101-NH2 for selective pre-concentration of chlorogenic acid metabolites in rat plasma,urine,and feces samples / 药物分析学报

An innovative sandwich-structural Fe-based metal-organic framework magnetic material(Fe3O4@SW-MIL-101-NH2)was fabricated using a facile solvothermal method.The characteristic properties of the material were investigated by field emission scanning electron microscopy,transmission electron mi-croscopy(TEM),energy-dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,X-ray powder diffraction,vibrating sample magnetometry,and Brunauer-Emmett-Teller measurements.Fe3O4@SW-MIL-101-NH2 is associated with advantages,such as robust magnetic properties,high specific surface area,and satisfactory storage stability,as well as good selective recognition ability for chlorogenic acid(CA)and its metabolites via chelation,hydrogen bonding,and π-interaction.The results of the static adsorption experiment indicated that Fe3O4@SW-MIL-101-NH2 possessed a high adsorption capacity toward CA and its isomers,cryptochlorogenic acid(CCA)and neochlorogenic acid(NCA),and the adsorption behaviors were fitted using the Langmuir adsorption isotherm model.Then,a strategy using magnetic solid-phase extraction(MSPE)and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF MS/MS)was developed and suc-cessfully employed for the selective pre-concentration and rapid identification of CA metabolites in rat plasma,urine,and feces samples.This work presents a prospective strategy for the synthesis of magnetic adsorbents and the high-efficiency pretreatment of CA metabolites.

Clinical study on minimally invasive liquefaction and drainage of intracerebral hematoma in the treatment of hypertensive putamen hemorrhage.

OBJECTIVE: This study aims to compare the curative effect of different treatment methods of hypertensive putamen hemorrhage, in order to determine an ideal method of treatment; and to explore the curative effect of the application of soft channel technology-minimally invasive liquefaction and drainage of intracerebral hematoma in the treatment of hypertensive putamen hemorrhage. METHODS: Patients with hypertensive cerebral hemorrhage, who were treated in our hospital from January 2015 to January 2016, were included into this study. Patients were divided into three groups: minimally invasive drainage group, internal medical treatment group and craniotomy group. In the minimally invasive drainage group, puncture aspiration and drainage were performed according to different hematoma conditions detected in brain CT, the frontal approach was selected for putamen and intracerebral hemorrhage, and drainage was reserved until the hematoma disappeared in CT detection. Drug therapy was dominated in the internal medical treatment group, while surgery under general anesthesia was performed to remove the hematoma in the craniotomy group. RESULTS: Post-treatment neurological function defect scores in minimally invasive drainage group and internal medical group were 16.14 ± 11.27 and 31.43 ± 10.42, respectively; and the difference was remarkably significant (P< 0.01). Post-treatment neurological function defect scores in the minimally invasive drainage group and craniotomy group were 16.14 ± 11.27 and 24.20 ± 12.23, respectively; and the difference was statistically significant (P< 0.05). There was a remarkable significant difference in ADL1-2 level during followed-up in survival patients between the minimally invasive drainage group and internal medical treatment group (P< 0.01), and there was a significant difference in followed-up mortality between these two groups (P< 0.01). CONCLUSION: Clinical observation and following-up results revealed that minimally invasive drainage treatment was superior to internal medical treatment and craniotomy.

[Effect of Rho kinase on hypoxia stimulated proliferation of pulmonary arterial smooth muscle cells].

OBJECTIVE: To study whether Rho kinase is involved in the proliferation of pulmonary arterial smooth muscle cells (PASMCs) induced by hypoxia. METHODS: Rat's PASMCs were isolated and cultured. Methyl thiazolyl tetrazolium (MTT) was used to determine the growth of cells. The cell cycle was analyzed by flow cytometry. Western blot was used to assess the expression of Rho kinase. RESULTS: The results of MTT showed that the number of PASMCs was increased after exposure to low oxygen tension for 12 hours compared with PASMCs in normoxia. After exposure of PASMCs to hypoxia for 24 hours,the cellular proliferation peaked,and was higher than that of PASMCs exposed to normal oxygen tension, hypoxia and Y27632 (Rho kinase inhibitor) groups,then it declined when exposed for 48 hours. Analysis of cell cycle indicated that the ability of cell proliferation increased significantly in PASMCs exposed to hypoxia compared with normoxia. Rho kinase level was higher in PASMCs exposed to hypoxia compared with normoxia. CONCLUSION: Hypoxia stimulates proliferation of PASMCs and promotes PASMCs into the phase of mitosis. The expression of Rho kinase is increased in PASMCs that are exposed to hypoxia, and it shows that Rho kinase is activated by hypoxia in PASMCs. Rho kinase maybe involve in the proliferation of PASMCs induced by hypoxia.

[Different expression and significance of VEGF and PCNA in aorta and pulmonary artery smooth muscle cells of rats with hypoxia pulmonary hypertension].

AIM: To study the expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen(PCNA) in aorta and pulmonary artery smooth muscle cells of rats with hypoxia pulmonary hypertension(HPH). METHODS: The rat chronically HPH models were set up in the hypobaric hypoxia cabin. The experimental rats were divided into 3 groups: control group (rearing in a normoxia environment), two hypoxia groups (oxygen-deficient time being 2 weeks and 3 weeks, respectively). Expression of VEGF and PCNA were detected by immunohistochemical staining and image analysis. RESULTS: There was VEGF expression in vascular smooth muscle cells of aorta, pulmonary artery trunk and pulmonary arteriole in control group. In two hypoxia groups VEGF expression in vascular smooth muscle cells of pulmonary artery, trunk and pulmonary arteriole increased significantly, while no difference was found in smooth muscle cells of aorta. Expression of PCNA was very little in vascular smooth muscle cells of aorta, pulmonary artery trunk and pulmonary arteriole in control group. In two hypoxia groups, the PCNA expression increased only in vascular smooth muscle cells of pulmonary arteriole; there was no difference of PCNA expression in vascular smooth muscle cells of aorta and pulmonary artery trunk between hypoxia groups and control group. CONCLUSION: There is difference of VEGF expression in pulmonary artery trunk and aorta smooth muscle cells during the formation of chronic HPH, suggesting that VEGF expression may play very important role in the formation of chronic HPH.

[Cellular ultrastructural changes of bone marrow of patients with hemorrhagic fever with renal syndrome].

BACKGROUND: To observe cytopathogenic effect of Hantaan virus (HV) on cultured human bone marrow cells. METHODS: Light and transmission electron microscopy and direct immunofluorescent technique were applied to study cellular structure especially ultrastructural changes of bone marrow cells from patients with Hantaan virus infection. Bone marrow cells of one healthy volunteer were also studied as control. RESULTS: The antigen of HV was found in bone marrow cells of 20 of 27 HFRS patients by the aid of direct immunofluorescent technique. It was found that the granulocytes had the highest percentage of HV antigen positive cells (76%), followed by monocytes (65%), lymphocytes (40%), megakaryocytes (20%) and the lowest was found in erythrocytes (3.7%). The injury of cell membrane after infection with HV was significantly more severe than that in the control group under the light and electron microscopy. CONCLUSION: This study demonstrated that HV could attack human bone marrow cells and cause cytopathogenic effect on them.