A novel method for detecting circulating tumor cells immunity based on micro-nano technique / 生物工程学报

This study was to develop a new method for detecting circulating tumor cells (CTCs) with high sensitivity and specificity, therefore to detect the colorectal cancer as early as possible for improving the detection rate of the disease. To this end, we prepared some micro-column structure microchips modified with graphite oxide-streptavidin (GO-SA) on the surface of microchips, further coupled with a broad-spectrum primary antibody (antibody1, Ab1), anti-epithelial cell adhesion molecule (anti-EpCAM) monoclonal antibody to capture CTCs. Besides, carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) were coupled with colorectal cancer related antibody as specific antibody 2 (Ab2) to prepare complex. The sandwich structure consisting of Ab1-CTCs-Ab2 was constructed by the microchip for capturing CTCs. And the electrochemical workstation was used to detect and verify its high sensitivity and specificity. Results showed that the combination of immunosensor and micro-nano technology has greatly improved the detection sensitivity and specificity of the immunosensor. And we also verified the feasibility of the immunosensor for clinical blood sample detection, and successfully recognitized detection and quantization of CTCs in peripheral blood of colorectal cancer patients by this immunosensor. In conclusion, the super sandwich immunosensor based on micro-nano technology provides a new way for the detection of CTCs, which has potential application value in clinical diagnosis and real-time monitoring of disease.

Could cerebrospinal fluid biomarkers offer better predictive value for spinal cord ischaemia than current neuromonitoring techniques during thoracoabdominal aortic aneurysm repair - a systematic review

Abstract Objective: Cerebrospinal fluid (CSF) drainage is a technique that has significantly reduced the incidence of spinal cord ischaemia (SCI). We present results of a systematic review to assess the literature on this topic in relation to thoracoabdominal aortic aneurysm repair (TAAR). Methods: Major medical databases were searched to identify papers related to CSF biomarkers measured during TAAAR. Results: Fifteen papers reported measurements of CSF biomarkers with 265 patients in total. CSF biomarkers measured included S-100ß, neuron-specific endolase (NSE), lactate, glial fibrillary acidic protein A (GFPa), Tau, heat shock protein 70 and 27 (HSP70, HSP27), and proinflammatory cytokines. Lactate and S-100ß were reported the most, but did not correlate with SCI, which was also the case with NSE and TAU. GFPa showed significant CSF level rises, both intra and postoperative in patients who suffered SCI and warrants further investigation, similar results were seen with HSP70, HSP27 and IL-8. Conclusions: Although there is significant interest in this topic, there still remains a significant lack of high-quality studies investigating CSF biomarkers during TAAR to detect SCI. A large and multicentre study is required to identify the significant role of each biomarker.

An anti-passivation ink for the preparation of electrodes for use in electrochemical immunoassays / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

p-Nitrophenylphosphate (PNPP) is usually employed as the substrate for enzyme-linked immunosorbent assays. p-Nitrophenol (PNP), the product of PNPP, with the catalyst alkaline phosphatase (ALP), will passivate an electrode, which limits applications in electrochemical analysis. A novel anti-passivation ink used in the preparation of a graphene/ionic liquid/chitosan composited (rGO/IL/Chi) electrode is proposed to solve the problem. The anti-passivation electrode was fabricated by directly writing the graphene-ionic liquid-chitosan composite on a single-side conductive gold strip. A glassy carbon electrode, a screen-printed electrode, and a graphene-chitosan composite-modified screen-printed electrode were investigated for comparison. Scanning electron microscopy was used to characterize the surface structure of the four different electrodes and cyclic voltammetry was carried out to compare their performance. The results showed that the rGO/IL/Chi electrode had the best performance according to its low peak potential and large peak current. Amperometric responses of the different electrodes to PNP proved that only the rGO/IL/Chi electrode was capable of anti-passivation. The detection of cardiac troponin I was used as a test example for electrochemical immunoassay. Differential pulse voltammetry was performed to detect cardiac troponin I and obtain a calibration curve. The limit of detection was 0.05 ng/ml.

Detección de cortisol salival nocturno en una muestra de sujetos de Santiago de Chile, mediante la técnica deelectroquimioluminicencia / Night salivary cortisol measurement in a sample of volunteers from Santiago using an electroquimioluminicence technique

Cortisol is a glucocorticoid hormone with circadian cycle, it shows high levels in the morning and lower in the night. The salivary cortisol is the biologically active fraction and night measurement has been very useful for improving the diagnosis of Cushing’s syndrome, an endocrine disorder characterized by high levels of cortisol and loss of their circadian cycle. A disadvantage of this measurement is the establishment of reference ranges, which depends on the population and technique. Therefore the night salivary cortisol values were determined in a sample of 75 healthy volunteers, aged 18-75 years old. Each volunteer collects two samples in consecutive days and these samples were analyzed by electrochemiluminescence. The average of night salivary cortisol of volunteers was 0.165 +/- 0.059 ug/dL with a range from 0.082 to 0.352 ug/dL and no significant differences were found between two samples of cortisol in day 1 and 2. Our results suggest that the proposed cut-off limit 0.32 ug/dL between patients with and without Cushing Syndrome would be suitable for this technique and in our population.

A simple and sensitive method for determination of Norfloxacin in pharmaceutical preparations / Um método simples e sensível para determinação da norfloxacina em preparações farmacêuticas

In this approach, a new voltammetric method for determination of norfloxacin was proposed with high sensitivity and wider detection linear range. The used voltammetric sensor was fabricated simply by coating a layer of graphene oxide (GO) and Nafion composited film on glassy carbon electrode. The advantage of proposed method was sensitive electrochemical response for norfloxacin, which was attributed to the excellent electrical conductivity of GO and the accumulating function of Nafion under optimum experimental conditions, the present method revealed a good linear response for determination of norfloxacin in the range of 1×10^-8mol/L-7×10^-6 mol/L with a detection limit of 5×10^-9 mol/L. The proposed method was successfully applied in the determination of norfloxacin in capsules with satisfactory results...

Propos-se, por essa abordagem, novo método voltamétrico, com alta sensibilidade e faixa linear de detecção mais ampla, para a determinação de norfloxacino. O sensor voltamétrico utilizado foi fabricado simplismente por cobertura de camada de óxido de grafeno (GO) e filme de Nafion em eletrodo de cabrono vítreo. A vantagem do método proposto foi a resposta eletroquímica sensível para o norfloxacino, atribuída à condutividade elétrica excelente do GO e à função acumulada do Nafion. Sob condições experimentais ótimas, o presente método revelou boa resposta linear para a determinação do norfloxacino na faixa de limite de detecção de 1×10^-8mol/L-7×10^-6 mol/L. O método proposto foi aplicado com sucesso na determinação de norfloxacino em cápsulas, com resultados satisfatórios...

Differential pulse voltammetric determination of diclofenac in pharmaceutical preparations and human serum / Pulso diferencial determinação voltamétrica de diclofenaco em preparações farmacêuticas e em soro humano

This article describes a differential pulse voltammetric (DPV) method for the determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electro-oxidation of diclofenac at platinum electrode in 0.1 M TBAClO₄/acetonitrile solution. The well-defined two oxidation peaks were observed at 0.87 and 1.27 V, respectively. Calibration curves that obtained by using current values measured for second peak were linear over the concentration range of 1.5-17.5 μg mL^-1and 2-20 μg mL^-1 in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra- and inter-day precision values for diclofenac were less than 3.87, and accuracy (relative error) was better than 4.12%. The method developed in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. In addition, the proposed technique was successfully applied to spiked human serum samples. No electro-active interferences from the endogenous substances were found in human serum...

Este artigo descreve um método de voltametria de pulso diferencial (VPD) para a determinação de diclofenaco em preparações farmacêuticas e em soro humano. O método proposto foi baseado em eletroxidação de diclofenaco no eléctrodo de platina em solução 0,1 M TBAClO₄/acetonitrila. Dois picos de oxidação bem definidos foram observados em 0,87 e 1,27 V, respectivamente. As curvas de calibração obtidas utilizando-se valores de corrente medidos por segundo pico foram lineares no intervalo de concentração de 1,5-17,5 μg mL^-1e 2-20 μg mL^-1em eletrólito suporte e soro, respectivamente. Precisão e exatidão também foram verificadas em todos os meios. Valores de precisão intra- e inter-dia para o diclofenaco foram inferiores a 3.87 e a precisão (erro relativo) foi melhor do que 4,12%. O método desenvolvido neste estudo é exato, preciso e pode ser facilmente aplicado a Diclomec, Dicloflam e comprimidos Voltaren, como preparação farmacêutica. Além disso, a técnica proposta foi aplicada com sucesso em amostras de soro humano. Não se observaram interferências das substâncias endógenas no soro humano...

Silver artifacts protection by anticorrosive coatings

Many objects of cultural heritage constituted of bulk, plated silver or alloys are often displayed in museum show-cases or kept in depositories. The silverworks tarnish with time by reactions with atmospheric pollutant elements, namely sulfides forming silver sulfide. The blackish films thus formed make these artifacts inappropriate to display and have to be dealt with. Tarnish can be removed with a silver polish, by a chemical dip, an electrochemical reduction method or galvanic coupling with aluminum. Several methods have been developed to reduce silver tarnish such as silver alloying, surface treatment and coating. The protection system employed, has to follow the Venice Charter, to be removable and not to change the aesthetics of the object to be protected. In this study, silver alloys have been tested for corrosion under accelerated atmospheric corrosion conditions. A system of hexadecane-thiol [HOT] has been tried on silver coupons. An acrylic copolymer has also been used as the organic vehicle for dispersed nano-pigment of aluminum oxide. Several percentages of pigments have been tried to check on the system capabilities, without altering the visual effects of the surface. The different coating systems have been prepared and either brushed on the surface of the silver coupons or the silver coupons were immersed in the coating system. Alternate immersion testing in sulfide solution has been tried on the coupons. Electrochemical testing, visual observations and gloss measurements showed that the coating with 2% nano-AI2O3 and the hexadecane-thiol exhibit better protective properties than the plain acrylic

Corrosion inhibition of Cu in nitrate solution

The effect of ethylenediamine [ED] and acetic acid on the corrosion inhibition of copper in 0.1 M NaNO] was studied. The study involved electrochemical polarization methods, gravimetric measurements and scanning electron microscopy investigations [SEM]. Both of ED and concentrated solutions of acetic acid >/= 10[-3] M act as a promoter while diluted concentrations of acetic acid

Effects of electrolyte viscosity on the efficiency of the electrochemical removal of lead ions using porous flow-through electrodes

The current study addresses the effect of the electrolyte viscosity on the efficiency of porous flow-through electrode [PFTE] made up of stacked screens during the electrochemical removal of lead ions from flowing alkaline solutions. Two types of efficiencies characterize the overall behaviour of the PFTE, namely, the collection efficiency [ratio of the captured ions to the feed concentration] and the coulombic efficiency [percentage of the total current used for the electrodeposition of lead ions]. The increase in the electrolyte viscosity causes a decrease in the experimentally measured limiting current of the electrodeposition reaction at the same electrolyte flow rate, and hence the collection efficiency decreases correspondingly. Also, the coulombic efficiency decreases with the increase of the electrolyte viscosity. This is attributed to the consequences of decreasing the diffusivity and the interfacial mass transfer coefficient of lead ions with the increase of electrolyte viscosity. On the other hand, the conductivity of the electrolyte has no effect on the limiting current

Electrochemical behavior of copper electrode in different solutions of adrenalin chydrogentatrate and catechol

Galvanic anodic polarization of copper electrode at different current densities in electrolytes of different pH values containing adrenaline hydrogen tartarte [AHT] and catechol [Cat.] have been studied. The effect of complex formation on the underlying anodic reactions and inhibition effect of these complexes on copper electrode is also studied. The cathodic deposition of copper in the prepared complexes on the surface of the cathode is involved to check their stability at different pH values and the effect of this stability on cathodic behavior of copper electrode