Disposable Electrochemical Sensors for Highly Sensitive Detection of Chlorpromazine in Human Whole Blood Based on the Silica Nanochannel Array Modified Screen-Printed Carbon Electrode

Rapid and highly sensitive quantitative analysis of chlorpromazine (CPZ) in human whole blood is of great importance for human health. Herein, we utilize the screen-printed carbon electrodes (SPCE) as the electrode substrates for growth of highly electroactive and antifouling nanocomposite materials consisting of vertically ordered mesoporous silica films (VMSF) and electrochemically reduced graphene oxide (ErGO) nanosheets. The preparation of such VMSF/ErGO/SPCE could be performed by using an electrochemical method in a few seconds and the operation is controllable. Inner ErGO layer converted from graphene oxide (GO) in the growth process of VMSF provides oxygen-containing groups and two-dimensional π-conjugated planar structure for stable fabrication of outer VMSF layer. Owing to the π-π enrichment and excellent electrocatalytic abilities of ErGO, electrostatic preconcentration and antifouling capacities of VMSF, and inherent disposable and miniaturized properties of SPCE, the proposed VMSF/ErGO/SPCE sensor could be applied for quantitative determination of CPZ in human whole blood with high accuracy and sensitivity, good stability, and low sample consumption.     

Anti-Biofouling Electrochemical Sensor Based on the Binary Nanocomposite of Silica Nanochannel Array and Graphene for Doxorubicin Detection in Human Serum and Urine Samples

A disposable and portable electrochemical sensor was fabricated by integrating vertically-ordered silica mesoporous films (VMSF) and electrochemically reduced graphene (ErGO) on a screen-printed carbon electrode (SPCE). Such VMSF/ErGO/SPCEs could be prepared by a simple and controllable electrochemical method. Stable growth of VMSF on SPCE could be accomplished by the introduction of an adhesive ErGO nanolayer owing to its oxygen-containing groups and two-dimensional (2D) planar structure. An outer VMSF layer acting as a protective coating is able to prevent the leakage of the inner ErGO layer from the SPCE surface. Thanks to the electrostatic permselectivity and anti-fouling capacity of VMSF and to the good electroactive activity of ErGO, binary nanocomposites of VMSF and ErGO endow the SPCE with excellent analytical performance, which could be used to quantitatively detect doxorubicin (DOX) in biological samples (human serum and urine) with high sensitivity, good long-term stability, and low sample amounts.     

Electrochemical Determination of Dopamine Using a Poly(3,4-Ethylenedioxythiophene)-Reduced Graphene Oxide-Modified Glassy Carbon Electrode

Poly(3,4-ethylenedioxythiophene) was deposited on a reduced graphene oxide-decorated glassy carbon electrode through an electrochemical polymerization. The resulting glassy carbon electrode-reduced graphene oxide-poly(3,4-ethylenedioxythiophene) electrode was applied as an electrochemical biosensor for the determination of dopamine in the presence of ascorbic acid and uric acid. The material deposited on glassy carbon electrode was investigated in terms of morphology and structural analysis. The comparison of electrochemical behavior of the glassy carbon electrode-reduced graphene oxide-poly(3,4-ethylenedioxythiophene) electrode with the glassy carbon electrode-graphene oxide, glassy carbon electrode-reduced graphene oxide, and glassy carbon electrode-poly(3,4-ethylenedioxythiophene) electrodes exhibited high electrocatalytic activity for dopamine detection. Electrochemical kinetic parameters of glassy carbon electrode-reduced graphene oxide-poly(3,4-ethylenedioxythiophene), including the charge transfer coefficient α (0.49) and electron transfer rate constant k_s (1.04), were determined and discussed. The glassy carbon electrode-reduced graphene oxide-poly(3,4-ethylenedioxythiophene) electrode was studied for the determination of dopamine by differential pulse voltammetry and exhibited a linear range from 19.6 to 122.8?µM with a sensitivity of 3.27?µA?µM^?1?cm^?2 and a detection limit of 1.92?µM. The developed biosensor exhibited good selectivity toward dopamine with high reproducibility and stability.     

多巴胺在电沉积石墨烯修饰碳分子线电极上的电化学测定

以分子线二苯乙炔为修饰剂和粘合剂制备了一种新型的碳糊电极-碳分子线电极(CMWE),并以其为基底电极采用电化学还原法将石墨烯(GR)沉积到CMWE表面得到电沉积石墨烯修饰碳分子线电极(GR/CMWE)。考察了多巴胺(DA)在该修饰电极上的电化学行为。实验结果显示DA在GR/CMWE上出现了1对峰形良好的氧化还原峰,与裸电极相比,该氧化还原峰的电流增大,峰电位差减小,表明修饰电极对DA的电化学反应有催化作用。在最佳实验条件下峰电流与DA浓度在8.0×10-7~2.0×10-3mol/L范围内呈良好的线性关系,检出限(3σ)为2.55×10-7mol/L。将该电极用于多巴胺注射液样品的检测,结果满意。     

基于适配体的石墨烯修饰玻碳电极检测卡那霉素

建立了一种基于适配体和石墨烯修饰玻碳电极检测卡那霉素的方法。卡那霉素适配体(Kanaaptamer)可以吸附在石墨烯(Gr)修饰的电极表面,从而阻碍电化学探针[Fe(CN)6]3-/4-与电极表面的电子传递,然而与含有卡那霉素的样品反应后,卡那霉素能与适配体结合并使其从电极上置换脱落,对界面电子传递的阻碍作用降低,探针的电化学信号得到恢复。通过循环伏安法和原子力显微镜法对该过程进行了表征。该原理被用于对卡那霉素进行电化学检测,结果表明:在优化条件下,用差分脉冲伏安法(DPV)检测卡那霉素时,其线性范围为1×10-6~1×10-5mol/L,检出限为5×10-7mol/L。该方法应用于牛奶样品中卡那霉素的检测,结果满意。     

Nanochannel Array on Electrochemically Polarized Screen Printed Carbon Electrode for Rapid and Sensitive Electrochemical Determination of Clozapine in Human Whole Blood

Rapid and highly sensitive determination of clozapine (CLZ), a psychotropic drug for the treatment of refractory schizophrenia, in patients is of great significance to reduce the risk of disease recurrence. However, direct electroanalysis of CLZ in human whole blood remains a great challenge owing to the remarkable fouling that occurs in a complex matrix. In this work, a miniaturized, integrated, disposable electrochemical sensing platform based on the integration of nanochannel arrays on the surface of screen-printed carbon electrodes (SPCE) is demonstrated. The device achieves high determination sensitivity while also offering the electrode anti-fouling and anti-interference capabilities. To enhance the electrochemical performance of SPCE, simple electrochemical polarization including anodic oxidation and cathodic reduction is applied to pretreat SPCE. The electrochemically polarized SPCE (p-SPCE) exhibits an enhanced electrochemical peak signal toward CLZ compared with bare SPCE. An electrochemically assisted self-assembly method (EASA) is utilized to conveniently electrodeposit a vertically ordered mesoporous silica nanomembrane film (VMSF) on the p-SPCE, which could further enrich CLZ through electrostatic interactions. Owing to the dual signal amplification based on the p-SPCE and VMSF nanochannels, the developed VMSF/SPCE sensor enables determination of CLZ in the range from 50 nM to 20 μM with a low limit of detection (LOD) of 28 nM (S/N = 3). Combined with the excellent anti-fouling and anti-interference abilities of VMSF, direct and sensitive determination of CLZ in human blood is also achieved.     

Graphene and Carbon Nanotube-based Electrochemical Sensing Platforms for Dopamine

Dopamine (DA) is an important neurotransmitter, which is created and released from the central nervous system. It plays a crucial role in human activities, like cognition, emotions, and response to anything. Maladjustment of DA in human blood serum results in different neural diseases, like Parkinson's and Schizophrenia. Consequently, researchers have started working on DA detection in blood serum, which is undoubtedly a hot research area. Electrochemical sensing techniques are more promising to detect DA in real samples. However, utilizing conventional electrodes for selective determination of DA encounters numerous problems due to the coexistence of other materials, such as uric acid and ascorbic acid, which have an oxidation potential close to DA. To overcome such problems, researchers have put their focus on the modification of bare electrodes. The aim of this review is to present recent advances in modifications of most used bare electrodes with carbonaceous materials, especially graphene, its derivatives, and carbon nanotubes, for electrochemical detection of DA. A brief discussion about the mechanistic phenomena at the electrode interface has also been included in this review.     

头孢哌酮在玻碳电极上的电化学行为及检测方法

应用循环伏安法、线性扫描伏安法和微分脉冲伏安法研究头孢哌酮在玻碳电极上的电化学行为,建立了应用伏安法定量检测头孢哌酮的新方法。头孢哌酮的电极过程为受吸附控制的不可逆过程,电极反应转移电子数和转移质子数均为2。头孢哌酮在pH1.0的1mol/LH3PO4-NaOH介质中,在+0.13V(vs.Ag/AgCl)电位处产生一灵敏的氧化峰,应用微分脉冲伏安法进行测定,该峰电流值Ip与头孢哌酮质量浓度在5.05×10-7～1.01×10-4g/mL范围内有良好的线性关系(R=0.9996),检出限为4.95×10-9g/mL,样品测定平均加标回收率达99.50%,相对标准偏差(RSD)为3.17%。     

石墨烯复合材料电化学免疫传感器在肿瘤标志物检测中的应用

监测肿瘤标志物水平变化是评估肿瘤治疗效果的重要方法.基于石墨烯复合材料构建的电化学免疫传感器可实现对肿瘤标志物的检测,检测灵敏度高、特异性好,是快速、准确分析肿瘤标志物含量的理想检测工具.本文重点阐述了石墨烯复合材料的电化学免疫传感器在肿瘤标志物检测中的应用进展.总结了其在肿瘤标志物检测中应用的优势和不足,最后对基于石...     

石墨烯-壳聚糖复合物修饰电极构建电化学免疫传感器对1-芘丁酸的检测研究

采用石墨烯(GS)和壳聚糖(CS)复合膜修饰玻碳电极(GS-CS/GCE),利用1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC)和N-羟基丁二酰亚胺(NHS)(4∶1)活化GS-CS/GCE,共价固定多环芳烃抗体(anti-PAHs),构建灵敏度高、稳定性好的非标记电流型免疫传感器,用于1-芘丁酸(PBA)的检测。运用扫描电子显微镜对GS-CS复合膜的形貌进行表征。在pH 7.0含10 mmol/L K3Fe(CN)6和0.1 mmol/L KCl的磷酸盐溶液中,通过循环伏安法和示差脉冲伏安法研究修饰电极表面的电化学性质,并考察了免疫传感器的电化学性能。研究表明,由于石墨烯和壳聚糖的协同作用,GS-CS修饰的玻碳电极在Fe(CN)64-/3-溶液中的峰电流明显增大,有利于提高免疫传感器的灵敏度。在优化实验条件下,电极表面的anti-PAHs抗体固定量显著提高,增强了电极的分子识别性能。由于anti-PAHs抗体-抗原结合物的导电性较差,免疫传感器的峰电流随着待测溶液中PBA浓度的增大而减小,PBA浓度在0.1～80μg/L范围内呈良好的线性关系,检出限为0.03μg/L。该免疫传感器重现性好、特异性强,用于实际样品的测定,回收率为90%～105%。     

Pd/石墨烯/玻碳电极检测4-氯酚污染物的研究

采用改进的Hummers法和硼氢化钠还原法制备Pd/石墨烯催化剂,并采用XRD、SEM、XPS、TEM等技术对其进行表征. 将该催化剂修饰于玻碳电极表面,制备出Pd/石墨烯/玻碳电极,使用循环伏安法研究了检测4-氯酚的最佳工作条件. 研究结果表明,所得石墨烯表面平整光滑,以零价态存在的Pd纳米颗粒均匀分散到石墨烯上,平均粒径为(6.5 ± 0.05) nm. 检测4-氯酚的最佳支持电解质为0.1 mol?L-1、pH = 6.8的磷酸-磷酸钠缓冲溶液（PBS）,峰电流与扫描速率的平方根呈良好的线性关系（R2 = 0.992）,该电极的线性范围为1 ~ 100 μmol?L-1 (R2 = 0.967),检测限为0.57 μmol?L-1 (S/N = 3),且具有良好的重现性和稳定性. 本文所研制的Pd/石墨烯/玻碳电极具有较高的催化活性,提供了一种简便快捷、重现性好的检测4-氯酚的方法.     

Electrochemical Detection of Three Monohydroxylated Polycyclic Aromatic Hydrocarbons Using Electroreduced Graphene Oxide Modified Screen‐printed Electrode

An electrochemical sensor for detection of three monohydroxylated polycyclic aromatic hydrocarbons (OH?PAHs) was fabricated by electrochemical reduction of graphene oxide (E‐rGO) on screen‐printed electrode (SPE). The E‐rGO film presents typical wrinkled structure with porous and cavity‐like nanostructure, providing large surface area, effective π‐electron system and high electrical conductivity. The developed E‐rGO/SPE sensor exhibits outstanding sensing performance for the target OH?PAHs, 2‐hydroxynaphthalene, 3‐hydroxyphenanthrene, and 1‐hydroxypyrene, within a linear range varying from 50–800 nM, 50–1150 nM, and 100–1000 nM, and with a limit of detection (LOD) of 10.1 nM, 15.3 nM, and 20.4 nM (S/N=3), respectively. The electrochemical sensor possesses excellent stability, acceptable reproducibility, and good anti‐interference ability. Additionally, the proposed sensor can be applied to the analysis of OH?PAHs in the urine samples with recoveries of 98.1–105.9 %.     

Development of an Aluminium Doped TiO2 Nanoparticles‐modified Screen Printed Carbon Electrode for Electrochemical Sensing of Vanillin in Food Samples

A new chemically modified electrode based on titanium dioxide nanoparticles (TiO₂‐NPs) has been developed. Aluminium was incorporated into the TiO₂‐NPs to prepare aluminium doped TiO₂ nanoparticles (Al‐TiO₂‐NPs). Aluminium doped TiO₂ nanoparticles‐modified screen printed carbon electrode (Al‐TiO₂‐NPs/SPCE) was employed as easy, efficient and rapid sensor for electrochemical detection of vanillin in various types of food samples. Al‐TiO₂‐NPs were characterized by energy‐dispersive X‐ray (EDX), transmission electron microscopy (TEM), and X‐ray diffraction (XRD) and analyses showing that the average particle sizes varied for the Al‐NPs (7.63 nm) and Al‐TiO₂‐NPs (7.47 nm) with spherical crystal. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to optimize the analytical procedure. A detection limit of vanillin was 0.02 μM, and the relative standard deviation (RSD) was 3.50 %, obtained for a 5.0 μM concentration of vanillin. The electrochemical behaviour of several compounds, such as vanillic acid, vanillic alcohol, p‐hydroxybenzaldehyde and p‐hydroxybenzoic, etc., generally present in natural vanilla samples, were also studied to check the interferences with respect to vanillin voltammetric signal. The applicability was demonstrated by analysing food samples. The obtained results were compared with those provided by a previous method based on liquid chromatography for determination of vanillin.     

Electrochemical Detection of Alloxan on Reduced Graphene Oxide Modified Glassy Carbon Electrode

Alloxan is a toxic reagent that strongly induces the diabetes by destroying insulin‐producing β‐cells in the pancreas of living organisms. The reduction product of alloxan is dialuric acid, which is responsible for the intracellular generation of ROS to enhance the stress in living cells to cause kidney disease or diabetic nephropathy. Herein, we studied for the first time the electrochemical properties of alloxan on reduced graphene oxide modified glassy carbon electrode (rGO/GCE) in 0.1 M phosphate buffer solution (PBS) at pH 7. The obtained results were compared with graphene oxide modified GCE (GO/GCE) and bare GCE surfaces. The modified rGO/GCE showed well defined redox couple with 10 fold increase in both reduction as well as oxidation peak current for alloxan than that of GO/GCE and bare GCE. Differential pulse voltammetry (DPV) technique shows the linear increase in both oxidation and reduction peak current of alloxan in the range of 30 μM to 3 mM with LOD of 1.2 μM. An amperometric signal of alloxan is also increases with respect to each addition of 50 μM of alloxan on rGO/GCE at constant potential of ?0.05 V. The linear range of alloxan is observed between 50 μM to 750 μM (S/N=3). This kind of rGO/GCE surface is more suitable platform or sensor matrix for estimating unknown concentration of alloxan molecule in the real biological systems.     

Indirect Electrochemical Determination of Ribavirin Using Boronic Acid-Diol Recognition on a 3-Aminophenylboronic Acid-Electrochemically Reduced Graphene Oxide Modified Glassy Carbon Electrode (APBA/ERGO/GCE)

A novel method for the indirect electrochemical determination of ribavirin based on boronic acid-diol recognition was developed using the platform as the sensing element. The device was constructed using a 3-aminophenylboronic acid (APBA)-electrochemically reduced graphene oxide (ERGO) modified electrode. When the electrode was immersed in a solution of ribavirin, complexation of boronic acid groups of APBA with ribavirin occurred at the surface of the electrode and simultaneously caused steric hindrance, resulting in a current decrease because the ferricyanide redox probe was unable access the surface. Under the optimized conditions, a linear relationship was obtained between the relative change in current (%Δi) of [Fe(CN)₆]^3?/4?and the concentration of ribavirin at levels from 10.0 to 7.50?×?10²?ng mL^?1. The proposed electrochemical sensor performed with acceptable sensitivity and reproducibility and was successfully used to determine the content of ribavirin in an injection with satisfactory results.     

Recent Advances of Carbon Nanotubes‐based Electrochemical Immunosensors for the Detection of Protein Cancer Biomarkers

An efficient electrochemical immunosensor can offer the potential for the detection of protein cancer biomarkers due to its high sensitivity, low cost and possible integration in compact analytical devices. In the last several years, researchers have developed various electrochemical immunoassay methods for the detection of protein cancer biomarkers. Significant progresses have been made in the study of electrochemical immunosensor that based on CNTs, especially in the fields of clinical screening and diagnosis of cancer field. This is because CNTs possess unique structural, mechanical and electronic properties that can decrease over‐potential and improve the sensitivity of electrochemical immunosensor. This paper reviews recent advances in the different modified strategies of constructing electrochemical immunosensor based on CNTs for detecting protein cancer biomarkers. CNTs or CNTs hybrid nanomaterials modified electrodes have been firstly introduced as the sensing platforms for the detection of protein cancer biomarkers. On the other hand, CNTs or functional CNTs used as labels in sandwich‐type electrochemical immunosensors have been systematically summarized. These novel strategies and the general principles could increase the sensitivity of the immunosensor, thereby overcoming the limitations of its application in the biosensing field.     

尿酸在石墨烯修饰玻碳电极上的电化学行为及测定

以抗坏血酸为还原剂,采用微波水热法化学还原氧化石墨烯合成了石墨烯纳米片,制备了石墨烯修饰的玻碳电极(RGO/GCE),并采用循环伏安法、计时电量法、交流阻抗法等电化学技术研究了尿酸在该修饰电极上的电化学行为及其影响因素。结果表明,在PBS缓冲溶液中,尿酸(UA)在石墨烯修饰电极上的电极反应是一个受扩散控制的不可逆氧化过程。电极反应的转移电子数n=2,有效面积A=0.182 cm2,扩散系数D=1.51×10-6 cm2.s-1。UA的氧化峰电流与其浓度在5.0×10-6～1.5×10-4 mol/L范围内呈良好线性,r=0.995 7。利用该RGO/GCE修饰电极可以快速准确地测定UA,检出限为2.7×10-7 mol/L,加标回收率为98%～100%。     

中空介孔碳球修饰的丝网印刷碳电极用于尼古丁的电化学检测

将一步法合成的中空介孔碳球(HMCS)修饰在丝网印刷碳电极(SPCE)上,得到了用于尼古丁电化学检测的新型电极(HMCS/SPCE)。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、粉末X射线衍射(XRD)、X射线光电子能谱(XPS)以及拉曼光谱等方法对HMCS及修饰电极HMCS/SPCE进行表征。由于HMCS具有较大的电化学活性面积和良好的导电性,修饰电极HMCS/SPCE对尼古丁表现出良好的电催化活性。在优化实验条件下,电极HMCS/SPCE对尼古丁的检测线性范围为0~500μmol/L,灵敏度为0.850 m A/(cm~2·mmol·L~(-1)),检出限为0.058μmol/L。制备的传感器具有重复性好、稳定性高等特点,可用于实际烟草样品中尼古丁的检测。     

纳米碳管电极的制备与电化学检测性能研究

纳米碳管由于其独特的物理和化学性能及广阔的应用前景而备受关注,其相关研究涉及到众多领域[1￣3]。在电化学分析领域,与其它碳电极材料相比,纳米碳管电极具有较大的电极表面积和较高的电子传递速率,其使用能增大响应电流、降低检出限,是目前电化学分析电极中一个十分引人注目     

鞣酸功能化石墨烯修饰电极上芦丁的电化学行为及灵敏检测

以双功能化试剂鞣酸一步还原法制备了鞣酸功能化的石墨烯纳米材料(TA-G)。鞣酸不仅起到还原剂的作用,还用作功能化试剂包裹石墨烯纳米片。将所制备的TA-G用于构建芦丁电化学传感器,可实现电化学信号放大并获得较好的检测灵敏度。电极反应动力学结果表明,芦丁在该修饰电极的电化学行为受表面准可逆过程控制。优化后的实验条件为p H 3.0,TA-G(1.0μg/m L)的电极修饰量为8μL,扫速为100m V/s,富集圈数为100圈。在优化条件下,芦丁的还原峰电流在1.0×10-8~1.0×10-5mol·L-1浓度范围内呈现良好的线性关系,检出限(S/N=3)为6.0×10-9mol/L。该传感器具有较高的稳定性、选择性和特异性,可实现实际样品中芦丁的灵敏检测,从而拓宽了石墨烯的应用领域并为药物的快速检测提供了新思路。