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1.
Electrogenerated chemiluminescence (ECL) for DNA hybridization detection is demonstrated based on DNA that was self-assembled onto a bare gold electrode and onto a gold nanoparticles modified gold electrode. A ruthenium complex served as an ECL tag. Gold nanoparticles were self-assembled on a gold electrode associated with a 1,6-hexanedithiol monolayer. The surface density of single stranded DNA (ssDNA) on the gold nanoparticle modified gold electrode was 4.8?×?1014 molecules per square centimeter which was 12-fold higher than that on the bare gold electrode. Hybridization was induced by exposure of the target ssDNA gold electrode to the solution of ECL probe consisting of complementary ssDNA tagged with ruthenium complex. The detection limit of target ssDNA on a gold nanoparticle modified gold electrode (6.7?×?10?12 mol L?1) is much lower than that on a bare gold electrode (1.2?×?10?10 mol L?1). The method has been applied to the detection of the DNA sequence related to cystic fibrosis. This work demonstrates that employment of gold nanoparticles self-assembled on a gold electrode is a promising strategy for the enhancement of the sensitivity of ECL detection of DNA. 相似文献
2.
Zhixian Gao Jie Ren Baoan Ning Huizhong Zhu Yonghong He 《International journal of environmental analytical chemistry》2013,93(8):599-606
Because of their high sensitivity, piezoelectric sensor techniques are extremely useful for environmental or clinical analysis. We developed a piezoelectric crystal DNA biosensor for the detection of the hybridization reaction based on the self-assembled monolayer technology and biotin–avidin system. 3,3′-Dithiopropionic acid was applied to form a self-assembled monolayer (SAM) on the gold surface of the quartz crystal. Avidin was coated on the gold electrode conjugated with 1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and then biotinylated nucleotide acids were immobilized on the gold electrode surface through the specific interaction of biotin and avidin. Our results indicated that, using this immobilization method, the piezoelectric DNA sensor shows a higher sensitivity and specificity in detecting the hybridization reaction. The sensor can be used repeatedly by electrode regeneration. 相似文献
3.
M. H. Pournaghi-Azar F. Ahour M. S. Hejazi 《Analytical and bioanalytical chemistry》2010,397(8):3581-3587
Development of an electrochemical DNA biosensor for the direct detection and discrimination of double-stranded oligonucleotide
(dsDNA) corresponding to hepatitis C virus genotype 3a, without its denaturation, using a gold electrode is described. The
electrochemical DNA sensor relies on the modification of the gold electrode with 6-mercapto-1-hexanol and a self-assembled
monolayer of 14-mer peptide nucleic acid probe, related to the hepatitis C virus genotype 3a core/E1 region. The increase
of differential pulse voltammetric responses of methylene blue, upon hybridization of the self-assembled probe with the target
ds-DNA to form a triplex is the principle behind the detection and discrimination. Some hybridization experiments with non-complementary
oligonucleotides were carried out to assess whether the developed DNA sensor responds selectively to the ds-DNA target. Diagnostic
performance of the biosensor is described and the detection limit was found to be 1.8 × 10−12 M in phosphate buffer solution, pH 7.0. The relative standard deviation of measurements of 100 pM of target ds-DNA performed
with three independent probe-modified electrodes was 3.1%, indicating a remarkable reproducibility of the detection method. 相似文献
4.
Fabrication of an Electrochemical E. coli Biosensor in Biowells Using Bimetallic Nanoparticle‐Labelled Antibodies
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Haslet Eksi Remziye Güzel Burcu Güven Ismail Hakki Boyaci Ali Osman Solak 《Electroanalysis》2015,27(2):343-352
An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in water. For this purpose, silver‐gold core‐shell (Ag@Au) bioconjugates and anti‐E. coli modified PS‐microwells were designed in a sandwich‐type format in order to obtain higher sensitivity and selectivity. Ag@Au bimetallic nanoparticles were synthesized by co‐reduction method. The core‐shell formation was analyzed by using UV‐Vis spectroscopy and transmission electron microscopy. Biotin labeled anti‐E. coli antibodies were coupled with Ag@Au nanoparticles to form bioconjugates. The electrochemical immunosensor was prepared by immobilizing anti‐E. coli on polystyrene (PS)‐microwells via chemical bonding. These modified microwells were identified with X‐ray photoelectron spectroscopy and surface enhanced Raman spectroscopy. E. coli was sandwiched between Ag@Au bioconjugates and anti‐E. coli on PS‐microwells at different concentrations. The relationship between the E. coli concentration and stripping current of gold ions (Au3+) were investigated by square wave anodic stripping voltammetry at pencil graphite electrode. The proposed method can provide some advantages such as lower detection limit and shorter detection time. The electrochemical response for the immunosensor was linear with the concentration of the E. coli in the range of 101 and 105 cfu/mL with a limit of detection 3 cfu/mL. The procedure maintains good sensitivity and repeatability and also offers utility in the fields of environmental monitoring and clinical diagnosis. 相似文献
5.
《Analytical letters》2012,45(17):2690-2704
A disposable immunosensor for the detection of Escherichia coli O157:H7 based on a multiwalled carbon nanotube–sodium alginate nanocomposite film was constructed. The nanocomposite was placed on a screen-printed carbon electrode, and horseradish peroxidase-labeled antibodies were immobilized to E. coli O157:H7 on the modified electrode to construct the immunosensor. The modification procedure was characterized by atomic force microscopy and cyclic voltammetry. Under optimal conditions, the proposed immunosensor exhibited good electrochemical sensitivity to E. coli O157:H7 in a concentration range of 103–1010 cfu/mL, with a relatively low detection limit of 2.94 × 102 cfu/mL (S/N = 3). This immunosensor exhibited satisfactory specificity, reproducibility, stability, and accuracy, making it a potential alternative tool for early assessment of E. coli O157:H7. 相似文献
6.
Yuxiao Cheng Yajun Liu Jingjing Huang Yuezhong Xian Zhonghai Zhang Litong Jin 《Electroanalysis》2008,20(13):1463-1469
A tyrosinase (Tyr) biosensor was fabricated by immobilizing Tyr on the surface of multiwalled carbon nanotubes (MWNTs)‐chitosan (Chit) composite modified glassy carbon electrode (GCE). The MWNTs‐Chit composite film provided a biocompatible platform for the Tyr to retain the bioactivity and the MWNTs possessed excellent inherent conductivity to enhance the electron transfer rate. The Tyr/MWNTs‐Chit/GCE biosensor showed high sensitivity (412 mA/M), broad linear response (1.0×10?8–2.8×10?5 M), low detection limit (5.0 nM) and good stability (remained 93% after 10 days) for determination of phenol. The biosensor was further applied to rapid detection of the coliforms, represented by Escherichia coli (E. coli) in this work. The current responses were proportional to the quantity of coliforms in the range of 104–106 cfu/mL. After 5.0 h of incubation, E. coli could be detected as low as 10 cfu/mL. 相似文献
7.
An electrochemical biosensor for the specific detection of short DNA sequences from the E. coli pathogen is described. This hybridization device relies on the immobilization of a 25-mer oligonucleotide probe, from the E. coli lacZ gene, onto a screen-printed carbon electrode. Chronopotentiometric detection of the Co(bpy)3+3 indicator is used for monitoring the hybridization event. Numerous variables of the assay protocol, including those of the probe immobilization step, the hybridization event, and the indicator association/detection, are characterized and optimized. Hybridization times of 2- and 30-min are sufficient for detecting 300- and 50 ng/mL, respectively, of the E. coli DNA target. Applicability to analysis of untreated environmental water samples is illustrated. Such single-use electrochemical sensors hold great promise for decentralized environmental and food testing for the E. coli pathogen. 相似文献
8.
《Analytical letters》2012,45(12):2048-2060
A Salmonella typhimurium (S. typhimurium) biosensor based on a fluorescence resonance energy transfer between upconversion and gold nanoparticles is reported. NaYF4:Yb,Er nanoparticles were synthesized and modified with a S. typhimurium target DNA complementary sequence to form the sensor. Gold nanoparticles were modified with a S. typhimurium target DNA complementary sequence to constitute the quenching probe. In the presence of S. typhimurium target DNA, gold and upconversion nanoparticles formed a sandwich complex, and the upconversion fluorescence resonance energy transfer occurred. Under the optimal conditions, the relative fluorescence was proportional to the concentration of S. typhimurium target DNA in the range of 0.001 pmol/L to 1 pmol/L with a limit of detection of 1 fM. S. typhimurium was detected from 30 cfu/mL to 5150 cfu/mL with a detection limit of 3 cfu/mL. The procedure was successfully applied to determine S. typhimurium in milk and validated by a traditional plate counting method. The developed upconversion fluorescence resonance energy transfer method is simple, fast, sensitive, specific, and incorporates nanomaterials in biosensor design. 相似文献
9.
Ezat Hamidi-Asl Jahan Bakhsh Raoof Reza Ojani Seyed Mahdi Golabi Mohammad Saeid Hejazi 《Journal of the Iranian Chemical Society》2013,10(6):1075-1083
In this paper, we report a new PNA biosensor for electrochemical detection of point mutation or single nucleotide polymorphism (SNP) in p53 gene corresponding oligonucleotide based on PNA/ds-DNA triplex formation following hybridization of PNA probe with double-stranded DNA (ds-DNA) sample without denaturing the ds-DNA into single-stranded DNA (ss-DNA). As p53 gene is mutated in many human tumors, this research is useful for cancer therapy and genomic study. In this approach, methylene blue (MB) is used for electrochemical signal generation and the interaction between MB and oligonucleotides is studied by differential pulse voltammety (DPV). Probe-modified electrode is prepared by self-assembled monolayer (SAM) formation of thiolated PNA molecules on the surface of Au electrode. A significant increase in the reduction signal of MB following hybridization of the probe with the complementary double-stranded oligonucleotide (ds-oligonucleotide) confirms the function of the biosensor. The selectivity of the PNA sensor is investigated by non-complementary ds-oligonucleotides and the results support the ability of the sensor to detect single-base mismatch directly on ds-oligonucleotide. The influence of probe and ds-DNA concentrations on the effective discrimination against complementary sequence and point mutation is studied and the concentration of 10?6 M is selected as appropriate concentration. Diagnostic performance of the biosensor is described and the detection limit is found to be 4.15 × 10?12 M. 相似文献
10.
A novel approach to construct an electrochemical DNA sensor based on immobilization of a 25 base single-stranded probe, specific to E. coli lac Z gene, onto a gold disk electrode is described. The capture probe is covalently attached using a self-assembled monolayer of 3,3′-dithiodipropionic acid di(N-succinimidyl ester) (DTSP) and mercaptohexanol (MCH) as spacer. Hybridization of the immobilized probe with the target DNA at the electrode surface was monitored by square wave voltammetry (SWV), using methylene blue (MB) as electrochemical indicator. Variables involved in the sensor performance, such as the DTSP concentration in the modification solution, the self-assembled monolayers (SAM) formation time, the DNA probe drying time atop the electrode surface and the amount of probe immobilized, were optimized.
A good stability of the single- and double-stranded oligonucleotides immobilized on the DTSP-modified electrode was demonstrated, and a target DNA detection limit of 45 nM was achieved without signal amplification. Hybridization specificity was checked with non-complementary and mismatch oligonucleotides. A single-base mismatch oligonucleotide gave a hybridization response only 7 ± 3%, higher than the signal obtained for the capture probe before hybridization. The possibility of reusing the electrochemical genosensor was also tested. 相似文献
11.
铂纳米颗粒修饰电极对大肠杆菌的电化学快速检测 总被引:2,自引:0,他引:2
本文采用了电化学沉积法制备了铂纳米颗粒化学修饰电极(PtNP/GCE),并将它应用于大肠杆菌的检测。原理是基于检测大肠杆菌溶液中酶与底物的反应产物,对氨基酚,实现了对大肠杆菌的快速检测。采用了铂纳米颗粒修饰电极,并对检测系统进行优化,提高大肠杆菌的检测灵敏度。大肠杆菌浓度在50—1.0×105cfu/ml与响应电流成良好的线性关系,最低检测限为20 cfu/ml,检测时间在4个小时以内。与传统方法相比,该电化学方法能很好地满足食品安全、环境监控和临床医学等领域中快速检测的要求。 相似文献
12.
Caihui Luo Yaning Lei Li Yan Tianxiao Yu Qing Li Decai Zhang Shijia Ding Huangxian Ju 《Electroanalysis》2012,24(5):1186-1191
A sensitive and specific electrochemical biosensor based on target‐induced aptamer displacement was developed for direct detection of Escherichia coli O111. The aptamer for Escherichia coli O111 was immobilized on a gold electrode by hybridization with the capture probe anchored on the electrode surface through Au‐thiol binding. In the presence of Escherichia coli O111, the aptamer was dissociated from the capture probe‐aptamer duplex due to the stronger interaction between the aptamer and the Escherichia coli O111. The consequent single‐strand capture probe could be hybridized with biotinylated detection probe and tagged with streptavidin‐alkaline phosphatase, producing sensitive enzyme‐catalyzed electrochemical response to Escherichia coli O111. The designed biosensor showed weak electrochemical signal to Salmonella typhimurium, Staphylococcus aureus and common non‐pathogenic Escherichia coli, indicating high specificity for Escherichia coli O111. Under the optimal conditions, the proposed strategy could directly detect Escherichia coli O111 with the detection limit of 112 CFU mL?1 in phosphate buffer saline and 305 CFU mL?1 in milk within 3.5 h, demonstrated the sensitive and accurate quantification of target pathogenic bacteria. The designed biosensor could become a powerful tool for pathogenic microorganisms screening in clinical diagnostics, food safety, biothreat detection and environmental monitoring. 相似文献
13.
Aisha Attar Fethi Achi Saliha Bourouina Bacha Mustapha Bourouina Laura Cubillana-Aguilera 《International journal of environmental analytical chemistry》2016,96(6):515-529
A novel inhibition biosensor used for the detection of sulphides (Na2S) has been developed. The biosensor is based on the immobilisation of horseradish peroxidase (HRP) on the Sonogel-Carbon (SNGC) electrode using glutaraldehyde, Poly(4-vinylpyridine) and gold sononanoparticles (AuSNPs). The Poly(4-vinylpyridine) was used due to its high affinity for sulphide anions, while the presence of gold sononanoparticles enhances the electron transfer reaction and improves the analytical performance of the biosensor. The amperometric measurements were performed at an applied potential of ?0.15 V vs. Ag/AgCl in 50 mM sodium acetate buffer solution pH = 6.0. The apparent kinetic parameters (Kmapp, Vmax) of immobilised HRP were calculated in the absence of inhibitor (sulphide) using caffeic acid as substrate. Under the optimal experimental conditions, the determination of sulphide can be achieved in a dynamic range of 0.4–2.8 µM with a low limit of detection of 0.15 µM. The electrochemical impedance spectroscopy (EIS) was also used to characterise the interactions of substrate and inhibitor with the enzyme-modified electrode. The developed biosensor exhibited high sensitivity, selectivity and stability, and can be successfully applied to the detection of sulphide in water. 相似文献
14.
《Analytical letters》2012,45(15):2849-2859
Abstract We have developed a novel nitric oxide (NO) cellular biosensor based upon the immobilization of red blood cells (RBCs) onto nanometer‐size colloidal gold that is attached to an electrochemically pretreated glassy carbon electrode via the bridging of an ethylenediamine monolayer. The biosensor has been characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemistry. The immobilized RBCs display an excellent electrocatalytic response to nitric oxide. The electrocatalytic currents are proportional to the NO concentration in the range from 1.0×10–8 to 1.0×10–6 M and the detection limit is as low as 5.0×10–9 M (S/N=3). Furthermore, the biosensor is very stable and relatively free of potential interference. 相似文献
15.
Srikant Sahoo Annareddy Venkata Ramana Reddy 《International journal of environmental analytical chemistry》2013,93(10):1050-1060
An electrochemical method was developed for the determination of mercury using polycrystalline gold electrode modified by self-assembled monolayers (SAMs) of 2-mercaptobenzothiazole (MBTH). Morphological and electrochemical characterisation of the self-assembled structure of MBTH was performed using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) measurements. The monolayer of MBTH has shown high affinity for Hg2+. The limit of detection for the determination of Hg2+ using the MBTH SAMs modified gold electrode was obtained as 0.421 μg L?1. The pre-concentration of Hg2+ at open circuit potential is beneficial for the onsite monitoring of mercury concentration in water samples. 相似文献
16.
Montserrat Cortina-Puig Xavier Muoz-Berbel Regis Rouillon Carole Calas-Blanchard Jean-Louis Marty 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):76
This paper describes the development of an amperometric cytochrome c (cyt c)-based biosensor and its later application to the quantification of the scavenging capacity of antioxidants. The enzymatic biosensor was constructed by covalently co-immobilizing both cyt c and XOD on a mercaptoundecanol/mercaptoundecanoic acid (MU/MUA) mixed self-assembled monolayer (SAM)-modified screen-printed gold electrode. The applicability of this method was shown by analyzing the antioxidant capacity of pure substances, such as ascorbic acid and Trolox, and natural sources of antioxidants, particularly 5 orange juices. 相似文献
17.
《Analytical letters》2012,45(6):1083-1095
Abstract A sensitive electrochemical DNA biosensor based on nano-ZnO/chitosan composite matrix for DNA hybridization detection was developed. The Nano-ZnO was synthesized by the hydrothermal method and dispersed in chitosan, which was used to fabricate the modification of the glassy carbon electrode (GCE) surface. The ZnO/chitosan-modified electrode exhibited good biocompatibility and excellent electrochemical conductivity. The hybridization detection was monitored with differential pulse voltammetry (DPV) measurement using methylene blue (MB) as an indicator. The established biosensor can effectively discriminate complementary target sequence and two-base-mismatched sequence, with a detection limit of 1.09 × 10?11 mol L?1 of complementary target. 相似文献
18.
The development of rapid, low-cost and reliable diagnostic methods is crucial for the identification and treatment of many diseases. Screen-printed gold electrodes (Au/SPEs), coated with a ternary monolayer interface, involving hexanedithiol (HDT), a specific thiolated capture probe (SHCP), and 6-mercapto-1 hexanol (MCH) (SHCP/HDT/MCH) are shown here to offer direct and sensitive detection of nucleic acid hybridization events in untreated raw biological samples (serum, urine and crude bacterial lysate solutions). The composition of the ternary monolayer was modified and tailored to the surface of the Au/SPE. The resulting SHCP/HDT/MCH monolayer has demonstrated to be extremely useful for enhancing the performance of disposable nucleic acid sensors based on screen-printed electrodes. Compared to common SHCP/MCH binary interfaces, the new ternary self-assembled monolayer (SAM) resulted in a 10-fold improvement in the signal (S)-to-noise (N) ratio (S/N) for 1 nM target DNA. The SHCP/HDT/MCH-modified Au/SPEs allowed the direct quantification of the target DNA down to 25 pM (0.25 fmol) and 100 pM (1 fmol) in undiluted/untreated serum and urine samples, respectively, and of 16S rRNA Escherichia coli (E. coli) corresponding to 3000 CFU μL−1 in raw cell lysate samples. The new SAM-coated screen-printed electrodes also displayed favorable non-fouling properties after a 24 h exposure to raw human serum and urine samples, offering great promise as cost-effective nucleic acid sensors for a wide range of decentralized genetic tests. 相似文献
19.
This work describes an approach for the development of two bacteria biosensors based on surface plasmon resonance (SPR) technique. The first biosensor was based on functionalized gold substrate and the second one on immobilized gold nanoparticles. For the first biosensor, the gold substrate was functionalized with acid-thiol using the self-assembled monolayer technique, while the second one was functionalized with gold nanoparticles immobilized on modified gold substrate. A polyclonal anti-Escherichia coli antibody was immobilized for specific (E. coli) and non-specific (Lactobacillus) bacteria detection. Detection limit with a good reproducibility of 104 and 103 cfu mL−1 of E. coli bacteria has been obtained for the first biosensor and for the second one respectively. A refractive index variation below 5 × 10−3 due to bacteria adsorption is able to be detected. The refractive index of the multilayer structure and of the E. coli bacteria layer was estimated with a modeling software. 相似文献
20.
《Analytical letters》2012,45(9):1698-1713
Abstract This work reports the development of a biosensor method for the label‐free detection of specific DNA sequences. In the initial phase, square wave voltammetry (SWV) was used in a comparative investigation into the electrochemical oxidation of purines (guanine and adenine) and DNA fragments at various electrode surfaces: carbon paste (CPE), glassy carbon electrode (GCE), and gold (AuE). Relative to the carbon electrodes, an approximate 4.0‐fold, 6.0‐fold, and 3.25‐fold increase in the anodic response was observed when guanine, adenine, and hydrolyzed DNA, respectively, were measured on the AuE. It was shown that the guanine and adenine bases could be successfully determined by use of SWV for a deoxyribonucleic acid sample following acid hydrolysis. This label‐free detection of hydrolyzed DNA on gold electrodes has significant advantages over methods using existing carbon electrode materials because of its higher sensitivity and the potential applicability of microfabrication techniques for the production of the requisite gold electrodes. In another phase of development, the times and conditions for DNA hydrolysis and purine release were investigated. It was shown that under optimal conditions, trace levels of the purine bases could be readily detected following 20 min of hydrolysis at room temperature. The proposed method can be used to estimate the guanine and adenine contents in DNA with in a linear range of 5–30 ng ml?1. Finally, when appropriate probe sequences were first adsorbed on the surface of the screen‐printed gold electrode (SPGE), this electrochemical biosensor could be used to specifically detect sequences from ss corona virus aviair following hybridization and hydrolysis reactions on the sensor surface. No enhancement of the voltammetric response was observed when the sensor was challenged with a non‐complementary DNA sequence. 相似文献