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Alex L Suherman, Sabine Kuss, Eden E L Tanner, Neil P Young, Richard G Compton
We report the electrochemical sensing of Hg2+ based on tannic acid capped gold nanoparticle (AuNP@TA) complexes. At optimal conditions using square wave voltammetry, the presented analytical method exhibits a "measurable lower limit" of 100.0 fM. This limit is considerably below the permissible level of 30.0 nM for inorganic mercury in drinking water, specified by the World Health Organization (WHO). The effect of potentially interfering ions, such as Zn2+ and Al3+, was studied and results indicate an excellent selectivity for Hg2+...
April 12, 2018: Analyst
Seyedeh Zeinab Mousavisani, Jahan Bakhsh Raoof, Reza Ojani, Zahra Bagheryan
The detection and inhibition of DNA damage are of great importance in the prevention and treatment of diseases. Developing a simple and sensitive tool for this purpose would be a chance to monitor the DNA damage and could be helpful in introducing some drugs which can prevent this phenomenon. Here, we report a novel and sensitive electrochemical biosensor based on DNA/Au nanoparticles (AuNPs) modified screen printed gold electrode (DNA/AuNPs/SPGE) to investigate the DNA damage process and also to study the protective behavior of deferoxamine (DFO)...
March 28, 2018: Bioelectrochemistry
Fei Cao, Yikun Huang, Fei Wang, Dongwook Kwak, Qiuchen Dong, Donghui Song, Jie Zeng, Yu Lei
As a new class of l-cysteine electrocatalyst explored in this study, Au/CeO2 composite nanofibers (CNFs) were employed to modify the screen printed carbon electrode (SPCE) to fabricate a novel l-cysteine (CySH) electrochemical sensor with high performance. Its electrochemical behavior and the roles of Au and CeO2 in the composite toward electro-oxidation of CySH were elucidated and demonstrated using cyclic voltammetry and amperometry techniques for the first time through the comparison with pure CeO2 NFs. More specifically, the Au/CeO2 CNFs modified SPCE possessed greatly enhanced electrocatalytic activity toward CySH oxidation...
August 17, 2018: Analytica Chimica Acta
Denise Capoferri, Ruslan Alvarez-Diduk, Michele Del Carlo, Dario Compagnone, Arben Merkoçi
Electrochromic effect and molecularly imprinted technology have been used to develop a sensitive and selective electrochromic sensor. The polymeric matrices obtained using the imprinting technology are robust molecular recognition elements and have the potential to mimic natural recognition entities with very high selectivity. The electrochromic behavior of iridium oxide nanoparticles (IrOx NPs) as physicochemical transducer together with a molecularly imprinted polymer (MIP) as recognition layer resulted in a fast and efficient translation of the detection event...
April 4, 2018: Analytical Chemistry
Hugues Brisset, Jean-François Briand, Raphaëlle Barry-Martinet, The Hy Duong, Pierre Frere, Frédéric Gohier, Philippe Leriche, Christine Bressy
Several alternatives are currently investigated to prevent and control the natural process of colonization of any seawater submerged surfaces by marine organisms. Since few years we develop an approach based on addressable electroactive coatings containing conducting polymers or polymers with lateral redox groups. In this article we describe the use of a screen-printed plate formed by 96 three-electrode electrochemical cells to assess the potential of these electroactive coatings to prevent the adhesion of marine bacteria...
April 3, 2018: Analytical Chemistry
Alexandra Plácido, Clara Pereira, Alexandra Guedes, M Fátima Barroso, Rebeca Miranda-Castro, Noemí de-Los-Santos-Álvarez, Cristina Delerue-Matos
The integration of nanomaterials in the field of (bio)sensors has allowed developing strategies with improved analytical performance. In this work, ultrasmall core-shell Fe3 O4 @Au magnetic nanoparticles (MNPs) were used as the platform for the immobilization of event-specific Roundup Ready (RR) soybean and taxon-specific DNA sequences. Firstly, monodisperse Fe3 O4 MNPs were synthesized by thermal decomposition and subsequently coated with a gold shell through reduction of Au(III) precursor on the surface of the MNPs in the presence of an organic capping agent...
March 21, 2018: Biosensors & Bioelectronics
A C Ward, A J Hannah, S L Kendrick, N P Tucker, G MacGregor, P Connolly
Staphylococcus aureus infections are a cause of significant morbidity and mortality, in addition to representing a considerable economic burden. The aim of this study was to explore a low cost screen printed electrode as a sensor for the detection of S. aureus using impedance spectroscopy. S. aureus was incubated in chambers containing the electrodes and the results analysed using a novel normalisation approach. These results show that it is possible to detect the presence of S. aureus in LB media after 30 min incubation of a 1% growth culture, in addition to being able to see immediate cell concentration dependant changes in 0...
March 22, 2018: Biosensors & Bioelectronics
Madasamy Thangamuthu, Christian Santschi, Olivier J F Martin
C-reactive protein (CRP) is one of the most expressed proteins in blood during acute phase inflammation, and its minute level increase has also been recognized for the clinical diagnosis of cardio vascular diseases. Unfortunately, the available commercial immunoassays are labour intensive, require large sample volumes, and have practical limitations, such as low stability and high production costs. Hence, we have developed a simple, cost effective, and label-free electrochemical immunoassay for the measurement of CRP in a drop of serum sample using an immunosensor strip made up of a screen printed carbon electrode (SPE) modified with anti-CRP functionalized gold nanoparticles (AuNPs)...
March 30, 2018: Biosensors
Anastasios Economou
This work reviews the field of screen-printed electrodes (SPEs) modified with "green" metals for electrochemical stripping analysis of toxic elements. Electrochemical stripping analysis has been established as a useful trace analysis technique offering many advantages compared to competing optical techniques. Although mercury has been the preferred electrode material for stripping analysis, the toxicity of mercury and the associated legal requirements in its use and disposal have prompted research towards the development of "green" metals as alternative electrode materials...
March 29, 2018: Sensors
Gema M Durán, Eulogio J Llorent-Martínez, Ana M Contento, Ángel Ríos
A voltammetric analytical assay for the selective quantification of vanillin is described. It is based on the use of a gold nanoparticle-modified screen-printed carbon electrode (SPCE) modified with graphene quantum dots (GQD) in a Nafion matrix. The GQD were synthesized by an acidic thermal method and characterized by UV-Vis, photoluminescence, and FTIR spectroscopy. The modified SPCE displays a strongly enhanced response to vanillin. Linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) were applied to optimize the methods...
March 3, 2018: Mikrochimica Acta
Maryam Hosseini Ghalehno, Mohammad Mirzaei, Masoud Torkzadeh-Mahani
An aptamer based method is presented for the voltammetric determination of human tumor necrosis factor alpha (TNF-α). Layers of gold hexacyanoferrate (AuHCF) and gold nanoparticles (AuNPs) were directly immobilized on a graphite screen-printed electrode (SPE). Through the strong interaction between cyanide ions (CN- ) of AuHCF and AuNPs, gold nanoparticles are assembled on the modified SPE, and this allows for the covalent immobilization of thiolated aptamers against TNF-α (TNF-α-Apt). On incubation of the aptasensor with of TNF-α, the Apt/TNF-α complex is formed, and this leads to a hindered electron transfer and to a decrease in the peak current of the redox probe...
February 10, 2018: Mikrochimica Acta
Mahmoud Roushani, Faezeh Shahdost-Fard
The authors describe a highly sensitive method for the aptamer (Apt) based impedimetric determination of cocaine. The surface of a screen-printed electrode (SPE) was modified with a nanocomposite of dendrimer and silver nanoparticles (AgNPs). The cocaine-binding Apt was attached to a dendrimer/AgNP/SPE surface, forming a sensitive layer for the determination of cocaine. The incubation with the analyte resulted in the formation of a cocaine/Apt complex on the electrode surface. As a consequence, folding and conformational change in the aptamer structure was induced, this resulting in a change in the impedimetric signal...
March 12, 2018: Mikrochimica Acta
Fanjun Zhu, Guangying Zhao, Wenchao Dou
The authors describe a sandwich-type of electrochemical immunoassay for rapid determination of the foodborne pathogen Cronobacter sakazakii (C. sakazakii). Polyclonal antibody against C. sakazakii (anti-C. sakazakii) and horseradish peroxidase were immobilized on a nanocomposite consisting of reduced graphene oxide, thionine and gold nanoparticles (AuNPs) that was placed on a screen-printed carbon electrode (SPCE). Thionine acts as an electron mediator which also shortens the electron transfer pathway from the conjugated HRP to the electrode surface and amplifies the electrochemical signal...
December 9, 2017: Mikrochimica Acta
Mahmoud Amouzadeh Tabrizi, Mojtaba Shamsipur, Reza Saber, Saeed Sarkar, Maryam Besharati
The authors describe an electrochemical method for aptamer-based determination of insulin at femtomolar concentrations. The surface of a screen printed electrode was modified with ordered mesoporous carbon that was chemically modified with 1,3,6,8-pyrenetetrasulfonate (TPS). The amino-terminated aptamer was then covalently linked to TPS via reactive sulfonyl chloride groups. Subsequently, the redox probe Methylene Blue (MB) was interacted into the aptamer. The MB-modified binds to insulin and this results in the release of MB and a decreased signal as obtained by differential pulse voltammetry, best at a working voltage of -0...
December 18, 2017: Mikrochimica Acta
Dan Li, Huazhen Duan, Yuhong Wang, Qinmei Zhang, Hairong Cao, Wei Deng, Dawei Li
The authors have developed a method for simultaneous quantification of several charged pesticides (as shown for amitrole, simazine, trichlorfon and bisultap). It is based on the use of a reduced graphene oxide-modified screen-printed electrode (RGO-SPE) and combines electrokinetic trapping (EKT) and surface-enhanced Raman scattering (SERS). When a 50 μL droplet containing negatively charged RGO and positively charged gold nanorods is placed on the SPE, the RGO and gold nanorods are selectively attracted on the surface of the SPE during EKT...
December 4, 2017: Mikrochimica Acta
Zufu Yao, Xin Yang, Xiaobo Liu, Yaqi Yang, Yangjian Hu, Zijian Zhao
An electrochemical quercetin (QR) sensor is described that is based on the use of magnetic reduced graphene oxide (MrGO) incorporated into a molecularly imprinted polymer (MIP) on the surface of a screen-printed electrode (SPE). The MrGO consists of reduced graphene oxide (rGO), magnetite (Fe3 O4 ) and silver nanoparticles (Ag). The analyte (QR) is electrostatically adsorbed on the surface of the MrGO. Finally, the MIP was deposited via in-situ polymerization. The composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Vibrating sample magnetometry...
December 20, 2017: Mikrochimica Acta
Nahid Shoaie, Mehdi Forouzandeh, Kobra Omidfar
The authors describe an electrochemical assay for fast detection of Escherichia coli (E. coli). It is based on a dual signal amplification strategy and the use of a screen-printed carbon electrode (SPCE) whose surface was modified with a polyaniline (PANI) film and gold nanoparticles (AuNPs) via cyclic voltammetry (CV). In the next step, avidin was covalently immobilized on the PANI/AuNP composite on the SPCE surface. Subsequently, the biotinylated DNA capture probe was immobilized onto the PANI/AuNP/avidin-modified SPCE by biotin-avidin interaction...
March 12, 2018: Mikrochimica Acta
Jafar Amani, Alireza Khoshroo, Mehdi Rahimi-Nasrabadi
The authors report on an electrochemical immunosensor for the tumor marker carbohydrate antigen 15-3 (CA15-3). It is based on the use of a composite consisting of reduced graphene oxide (RGO) and copper sulfide (CuS) that was placed on a screen-printed graphite electrode. The electrode shows excellent activity towards the oxidation of catechol acting as an electrochemical probe, best at a working potential of 0.16 V. The electrode was modified with antibody against CA15-3. Once the analyte (CA15-3) binds to the surface of the electrode, the response to catechol is reduced...
December 26, 2017: Mikrochimica Acta
Gustavo Hernandez-Vargas, Juan Eduardo Sosa-Hernández, Sara Saldarriaga-Hernandez, Angel M Villalba-Rodríguez, Roberto Parra-Saldivar, Hafiz M N Iqbal
The increasing environmental pollution with particular reference to emerging contaminants, toxic heavy elements, and other hazardous agents is a serious concern worldwide. Considering this global issue, there is an urgent need to design and develop strategic measuring techniques with higher efficacy and precision to detect a broader spectrum of numerous contaminants. The development of precise instruments can further help in real-time and in-process monitoring of the generation and release of environmental pollutants from different industrial sectors...
March 24, 2018: Biosensors
Juliana Oliveira, Vitor Correia, Enrico Sowade, Ikerne Etxebarria, Raul D Rodriguez, Kalyan Yoti Mitra, Reinhard R Baumann, Senentxu Lanceros-Méndez
Organic photodetectors based on printing technologies will allow to expand the current field of photodetector applications towards large-area and flexible applications in areas such as medical imaging, security and quality control, among others. Inkjet printing is a powerful digital tool for the deposition of smart and functional materials on various substrates, allowing the development of electronic devices such as photodetectors on various substrates. In this work, inkjet-printed photodetector array, based on organic thin-film transistor (OTFT) architecture, have been developed and applied for the indirect detection of X-ray radiation using a scintillator ink as X-ray absorber...
March 27, 2018: ACS Applied Materials & Interfaces
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