ABSTRACT
Rutin,a flavonoid found in fruits and vegetables,is a potential anticancer compound with strong anti-cancer activity.Therefore,electrochemical sensor was developed for the detection of rutin.In this study,CoWO4 nanosheets were synthesized via a hydrothermal method,and porous carbon(PC)was prepared via high-temperature pyrolysis.Successful preparation of the materials was confirmed,and character-ization was performed by transmission electron microscopy,scanning electron microscopy,and X-ray photoelectron spectroscopy.A mixture of PC and CoWO4 nanosheets was used as an electrode modifier to fabricate the electrochemical sensor for the electrochemical determination of rutin.The 3D CoWO4 nanosheets exhibited high electrocatalytic activity and good stability.PC has a high surface-to-volume ratio and superior conductivity.Moreover,the hydrophobicity of PC allows large amounts of rutin to be adsorbed,thereby increasing the concentration of rutin at the electrode surface.Owing to the syn-ergistic effect of the 3D CoWO4 nanosheets and PC,the developed electrochemical sensor was employed to quantitively determine rutin with high stability and sensitivity.The sensor showed a good linear range(5-5000 ng/mL)with a detection limit of O.45 ng/mL.The developed sensor was successfully applied to the determination of rutin in crushed tablets and human serum samples.
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Objective:To investigate the radiosensitizing effect of Ta 4C 3-PVP nanosheets on the tumor of 4T1 murine triple-negative breast cancer cells planted in mice. Methods:4T1 tumor-bearing mice model was established by subcutaneous injection of 4T1 cells into the right flank of the female BALB/c mice. The mice were divided into four groups uniformly according to their tumor size: blank control group, Ta 4C 3-PVP group, ionizing radiation (IR) group and Ta 4C 3-PVP plus IR group. A single dose of 8 Gy X-ray local irradiation was given to xenograft tumor at 24 h after tail intravenous injection of Ta 4C 3-PVP (20 mg/kg). The xenograft tumor volume and weight, the pathological changes of tumor tissue, the expression of tumor proliferative marker Ki-67 protein, and the formation of γ-H2AX foci [a DNA double-strand breaks (DSBs) molecular marker] were detected. Tumor growth curve was established, and enhancement factor (EF) and tumor inhibition rate were calculated. Results:Compared with the blank control group, tumor growth was significantly inhibited ( t=5.41, 9.59, P < 0.05) and tumor weight was markedly decreased ( t=2.67, 4.40, P < 0.05) in both IR group and Ta 4C 3-PVP plus IR group at day 16 after IR. The EF in Ta 4C 3-PVP plus IR group was 1.57, and tumor inhibition rate in Ta 4C 3-PVP plus IR group were about 64%, which was much higher than that of IR group alone(42%). Immunohistochemistry and immunofluorescence histochemistry assays showed that the expression of Ki-67 protein was obviously decreased and the amount of γ-H2AX foci was significantly increased in both IR group and Ta 4C 3-PVP plus IR group in comparison with the blank control group ( t=5.73, 8.02, 2.97, 9.86, P < 0.05). Moreover, the inhibition of Ki-67 protein expression and the increase of γ-H2AX foci were much higher in Ta 4C 3-PVP plus IR group than that in IR group ( t=4.75, 4.42, P < 0.05). Conclusions:Ta 4C 3-PVP nanosheets could enhance radiosensitivity of xenograft tumor in 4T1 tumor-bearing mice through increasing the IR-induced DNA DSBs.
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Carbon nanosheets load beta-cyclodextrin (β-CD-CNS) as a new modified electrode materials was reported for the electrochemical determination of sulfadiazine(SD). Carbon nanosheets(CNS) were prepared by a new method of ultrasonic electrolysis in which the β-CD was attached on CNS through ultrasonic dispersion method. The β-CD-CNS composite nanomaterials were immobilized onto glassy carbon electrodes with drops of coating method to construct an SD voltammetric sensor. The differential pulse stripping voltammetry (DPSV) was used to characterize the electrocatalytic behavior of the developed sensor. The Effects of some parameters on the response behavior of the sensor such as pH,modification amount,scanning rate,stirring speed,stirring time,deposition potential and time were investigated and optimized. The results indicated that the β-CD-CNS composite nanomaterials had excellent electroactivity for the SD in neutral solution and greatly improved the current response of SD. Under the optimal conditions, the SD had an irreversible characteristic oxidation peak around+0.87 V,and the oxidation peak current ip(μA) had a good linear relationship with the concentration C ( μmol/L) of the SD in concentration range of 0.05 μmol/L-13.5 μmol/L with correlation coefficients of 0.999. The detection limit was 12.2 nmol/L (S/N=3). The sensor was successfully applied for the trace SD determination in water and milk samples and the recoveries from the spiked samples were 80.0%-102% with RSD≤5.2%.
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Iron-doped titanium dioxide nanosheets was prepared by hydrothermal method using tetrabutyl titanate (C16H36O4Ti) and iron trifluoride (FeF3) and modified on ITO electrode.ITO/Fe : TiO2/CdS photoelectrochemical sensor was fabricated by successive ionic layer absorption and reaction(SILAR) method for determination of copper ion.The band gap of electode material was narrowed by iron doped TiO2 nanosheets,which made its absorption red-shifted and its response range of light was magnified.Based on the sensitization effect of CdS,the absorption and utilization of visible light of sensor was significantly enhanced and the photoelectric signal was amplified via reducing the recombination of electrons and holes.The sensor displayed excellent analytical performance for detection of copper ion with linear range of 0.2-4.0 μmol/L and 4.0-80.0 μmol/L and with the detection limit of 85 nmol/L.The sensor was used to detect copper ion in tap water,drinking water and Yongjiang river water with recoveries ranging from 94% to 111%.
ABSTRACT
Background: Hazards of graphene particles, as novel application in biomedicine and industry of electronics, have attracted extensive attention Large number of toxicological studies have evaluated the interactions of graphene nanomaterials with living systems Although many studies have been performed on graphene-induced toxic effects, toxicological data for the effect of graphene materials on the nervous system are lacking Aim: To follow whether graphene oxide nano-sheets (GONs) affect malonaldehyde (MDA), glutathione (GSH) and nitric oxide (NO) contents, also, mice brain neurotransmitters levels upon using different increasing doses at different time intervals Materials and methods: The present study focused on the biological effects of GONs, at 10, 50, 100, 250 and 500 µg/kg bw, on mice brain content of GSH, MDA and NO after 7, 28 and 56 days of injection Moreover, dopamine (DA), norepinephrine (NE) and 5-hydroxytryptamine (5-HT) levels, in mice brain, were also evaluated Results: Data obtained revealed significant decreases in GSH content coupled with significant increases in MDA and NO contents after GONs injection and these changes was dose and time dependent Meanwhile, DA and 5- HT levels s in mice brain revealed fluctuating responses, NE level showed significant elevations at different time intervals
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A colorimetric self-indicating probe for glucose was constructed by self-assembly of MnO2 nanosheets (MnO2 NSs) and glucose oxidase(GOD) in this paper.Under the weak acidic medium,glucose oxidase specifically catalyzes glucose into gluconic acid and hydrogen peroxide.The by-product of hydrogen peroxide could efficiently dissolve the MnO2 nanosheets,resulting into a significant decrease of the characteristic absorbance at 374 nm assigned to MnO2 NSs.Furthermore,the absorbance difference was linearly proportional to the concentration of glucose ranging from 1 to 20 μmol/L The fitted curve could be used for quantification of glucose with a correlation coefficient of 0.990 1.And the detection limit as low as 0.1 μmol/L could be reached based on the definition of three times of the deviation of the blank signal (3σ) and there was negligible interference with other co-existing amino acids,anions,cations and protein,which indicated high sensitivity and selectivity of the hybrid probe.The construction strategy of designated probe is readily generalized in principle for detection of numerous analytes in view of reactive property of MnO2 and the diversity of enzymes.
ABSTRACT
@#The aim of this study was to evaluate the potential application of layered double hydroxide(LDH)nanosheets for ocular drug delivery. Using LDH nanosheets as carriers, carboxymethyl cellulose(CMC)as a stabilizer and pirenoxine sodium(PRN)as the model drug, CMC-PRN-LDH nanosheets were prepared. PRN-LDHs nanoparticles were synthesized via co-precipitation method. X-ray diffraction, atomic force microscopy, transmission electron microscopy and laser particle sizer were employed to characterize the physicochemical properties of LDH nanosheets, CMC-LDH nanosheets and PRN-LDH nanocomposites. Stability, accumulative release in vitro and precorneal retention in vivo of both CMC-PRN-LDH nanosheets and PRN-LDHs nanoparticles were evaluated. It was found that CMC-PRN-LDH nanosheets were electrostatically stabilized by CMC absorbed on the surface of LDH nanosheets, but PRN-LDHs nanoparticles aggregated in phosphate buffered saline. 12-hr accumulative release percentage of PRN from CMC-PRN-LDH nanosheets and PRN-LDHs nanoparticles were 70. 44% and 44. 21% in vitro, respectively. Compared with the commercial PRN eye drops, there existed 4. 18-fold increase in AUC0-6 h and 1. 79-fold in mean retention time of CMC-PRN-LDH nanosheets. Negligible levels of PRN-LDHs nanoparticles might be attributed to inter-groups difference. Draize test showed that CMC-PRN-LDH nanosheets were non-irritant to the rabbit eyes after single and repeated dosing. It suggest that this novel LDH nanosheet could be a promising carrier for ocular drug delivery with prolonged residence time.