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Meng Chen, Ning Gan, You Zhou, Tianhua Li, Qing Xu, Yuting Cao, Yinji Chen
An ultrasensitive electrochemical aptasensor for simultaneous detection of oxytetracycline (OTC) and kanamycin (KAN) has been developed based on metal ions doped metal organic frame materials (MOFs) as signal tracers and RecJf exonuclease-catalyzed targets recycling amplification. The aptasensor consists of capture beads (the anti-single-stranded DNA Antibody, as anti-ssDNA Ab, labeled on Dynabeads) and nanoscale MOF (NMOF) based signal tracers (simplified as Apts-MNM, the NMOF labeled with metal ions and the aptamers)...
December 1, 2016: Talanta
Jiamian Wang, Jie Song, Xiuyun Wang, Shuo Wu, Yanqiu Zhao, Pinchen Luo, Changgong Meng
A label-free ratiometric fluorescence aptasensor has been developed for the rapid and sensitive detection of cocaine in complex biofluids. The fluorescent aptasensor is composed of a non-labeled GC-38 cocaine aptamer which serves as a basic sensing unit and two fluorophores, 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) and SYBR Green I (SGI) which serves as a signal reporter and a build-in reference, respectively. The detection principle is based on a specific cocaine mediated ATMND displacement reaction and the corresponding change in the fluorescence ratio of ATMND to SGI...
December 1, 2016: Talanta
R Rapini, A Cincinelli, G Marrazza
In this work, we propose an electrochemical DNA aptasensor for sensitive multidetection of acetamiprid based on a competitive format and disposable screen-printed arrays. To improve the sensitivity of the aptasensor, polyaniline film and gold nanoparticles were progressively electrodeposited on the graphite screen-printed electrode surface by cyclic voltammetry. Gold nanoparticles were then employed as platform for thiol-tethered DNA aptamer immobilization. Different acetamiprid solutions containing a fixed amount of biotinylated complementary oligonucleotide sequence by DNA aptasensor arrays were analyzed...
December 1, 2016: Talanta
Juan David Ospina-Villa, Absalom Zamorano-Carrillo, Carlos A Castañon-Sanchez, Esther Ramirez-Moreno, Laurence A Marchat
Aptamers are short single-stranded RNA or DNA oligonucleotides that are capable of binding various biological targets with high affinity and specificity. Their identification initially relies on a molecular process named SELEX (Systematic Evolution of Ligands by EXponential enrichment) that has been later modified in order to improve aptamer sensitivity, minimize duration and cost of the assay, as well as increase target types. Several biochemical modifications can help to enhance aptamer stability without affecting significantly target interaction...
October 15, 2016: Brazilian Journal of Infectious Diseases
Feriel Melaine, Clothilde Coilhac, Yoann Roupioz, Arnaud Buhot
Small molecules (MW < 1000 Da) represent a large class of biomarkers of interest. Recently, a new class of biosensors has been emerging thanks to the recognition properties of aptamers, short DNA or RNA single strands, selected against such small molecular targets. Among them, an adenosine-specific aptamer has been largely described and used due to its remarkable affinity to this small target (KD = 6 μM). In this paper, we achieved the proof-of-principle of an aptasensor based on the thermodynamic follow-up of adenosine binding with engineered split-aptamer sequences...
September 29, 2016: Nanoscale
Galina S Zamay, Tatiana N Zamay, Vasilii A Kolovskii, Alexandr V Shabanov, Yury E Glazyrin, Dmitry V Veprintsev, Alexey V Krat, Sergey S Zamay, Olga S Kolovskaya, Ana Gargaun, Alexey E Sokolov, Andrey A Modestov, Ivan P Artyukhov, Nikolay V Chesnokov, Marina M Petrova, Maxim V Berezovski, Anna S Zamay
The development of an aptamer-based electrochemical sensor for lung cancer detection is presented in this work. A highly specific DNA-aptamer, LC-18, selected to postoperative lung cancer tissues was immobilized onto a gold microelectrode and electrochemical measurements were performed in a solution containing the redox marker ferrocyanide/ferricyanide. The aptamer protein targets were harvested from blood plasma of lung cancer patients by using streptavidin paramagnetic beads and square wave voltammetry of the samples was performed at various concentrations...
October 3, 2016: Scientific Reports
Huihui Wang, Pai Peng, Shuangna Liu, Tao Li
Here, we for the first time demonstrated thioflavin T (ThT) as an efficient fluorescent ligand for 27-mer ATP-binding aptamer (ABA27), providing a novel signal readout mode for label-free selective ATP detection. ABA27 can promote the fluorescence emission of ThT with an unprecedentedly high efficiency, attributed to the specific structure of ABA27 rather than the G-tracts. Polyacrylamide gel electrophoresis, fluorescence spectroscopy, and fluorometric titration reveal that ThT interacts with ABA27 with a lower binding affinity (Kd ~89 μM) than ATP, which allows ATP to easily compete with ThT for the DNA binder...
November 2016: Analytical and Bioanalytical Chemistry
Quanwei Song, Ruihua Wang, Feifei Sun, Hongkun Chen, Zoumengke Wang, Na Na, Jin Ouyang
Owing to their promising advantages in biochemical analysis, aptamer-based sensing systems for the fluorescence detection of important biomolecules are being extensively investigated. Herein, we propose a turn-on fluorescent aptasensor for label-free detection of adenosine triphosphate (ATP) by utilizing the in situ formation of copper nanoparticles (CuNPs) and the specific digestion capability of exonuclease I (Exo I). In this assay, the addition of ATP can effectively hinder the digestion of aptamer-derived oligonucleotides due to the G-quadruplex structure...
September 9, 2016: Biosensors & Bioelectronics
Faezeh Shahdost-Fard, Mahmoud Roushani
In this paper, for the first time a highly sensitive and low-cost electrochemical aptasensor was fabricated based on a silver nanoparticles/thiol functionalized graphene quantum dot (AgNPs/thiol-GQD) nanocomposite for the measurement of 2,4,6-Trinitrotoluen (TNT) as a nitroaromatic explosive. For the first time Rutin (RU) as a biological molecule with inherent properties was used as the redox probe in the development of the TNT aptasensor was used. The system was based on a TNT-binding aptamer which is covalently attached onto the surface of a glassy carbon electrode (GCE) modified with the nanocomposite for the formation of a sensing layer and improving the performance of the aptasensor...
September 14, 2016: Biosensors & Bioelectronics
Priyamvada Jain, Smita Das, Babina Chakma, Pranab Goswami
A 90 mer ssDNA aptamer (P38) enriched against Plasmodium falciparum lactate dehydrogenase (PfLDH) through SELEX process was immobilized over glassy carbon electrode (GCE) using graphene oxide (GO) as an immobilization matrix, and the modified electrode was investigated for detection of PfLDH. The GO was synthesized from powdered pencil graphite and characterized by XRD based on the increased interlayer distance between graphitic layers from 0.345 nm for graphite to 0.829 nm for GO. The immobilization of P38 on GO was confirmed by ID/IG intensity ratio in Raman spectra where, the ratio were 0...
December 1, 2016: Analytical Biochemistry
Nirmal Prabhakar, Himkusha Thakur, Anu Bharti, Navpreet Kaur
An electrochemical aptasensor based on chitosan-iron oxide nanocomposite (CHIT-IO) film deposited on fluorine tin Oxide (FTO) was developed for the detection of malathion. Iron oxide nanoparticles were prepared by co-precipitation method and characterized by Transmission electron microscopy and UV-Visible spectroscopy. The biotinylated DNA aptamer sequence specific to the malathion was immobilized onto the iron oxide doped-chitosan/FTO electrode by using streptavidin as linking molecule. Various characterization studies like Field Emission-Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Electrochemical studies were performed to attest the successful fabrication of bioelectrodes...
October 5, 2016: Analytica Chimica Acta
P Zubiate, C R Zamarreño, P Sánchez, I R Matias, F J Arregui
This work presents the development of high sensitive, selective, fast and reusable C-reactive protein (CRP) aptasensors. This novel approach takes advantage of the utilization of high sensitive refractometers based on Lossy Mode Resonances generated by thin indium tin oxide (ITO) films fabricated onto the planar region of d-shaped optical fibers. CRP selectivity is obtained by means of the adhesion of a CRP specific aptamer chain onto the ITO film using the Layer-by-Layer (LbL) nano-assembly fabrication process...
September 8, 2016: Biosensors & Bioelectronics
Kewei Wang, Ruihua Zhang, Na Sun, Xinpan Li, Jine Wang, Yi Cao, Renjun Pei
A near-infrared-driven photoelectrochemical aptasensor was developed as a new method for the detection of the breast cancer cell MCF-7. The upconversion nanoparticles and TiO2/CdTe heterostructure were combined to prepare the film electrode, and the high-affinity aptamer AS1411 was conjugated to the electrode to recognize MCF-7 cells. In this fabrication, the upconversion nanoparticles transferred the near-infrared light to visible light, which could excite the semiconductor to enhance the current response...
October 5, 2016: ACS Applied Materials & Interfaces
Gaoshang Du, Lumei Wang, Dongwei Zhang, Xuan Ni, Xiaotong Zhou, Hanyi Xu, Lurong Xu, Shijian Wu, Tong Zhang, Wenhao Wang
This paper proposes an aptasensor for progesterone (P4) detection in human serum and urine based on the aggregating behavior of gold nanoparticles (AuNPs) controlled by the interactions among P4-binding aptamer, target P4 and cationic surfactant hexadecyltrimethylammonium bromide (CTAB). The aptamer can form an aptamer-P4 complex with P4, leaving CTAB free to aggregate AuNPs in this aptasensor. Thus, the sensing solution will turn from red (520 nm) to blue (650 nm) in the presence of P4 because P4 aptamers are used up firstly owing to the formation of an aptamer-P4 complex, leaving CTAB free to aggregate AuNPs...
December 1, 2016: Analytical Biochemistry
Mojtaba Shamsipur, Leila Farzin, Mahmoud Amouzadeh Tabrizi, Maryam Shanehsaz
A "signal off" voltammetric aptasensor was developed for the sensitive and selective detection of ultra-low levels of adenosine triphosphate (ATP). For this purpose, a new strategy based on the principle of recognition-induced switching of aptamers from DNA/DNA duplex to DNA/target complex was designed using thioglycolic acid (TGA)-capped CdTe quantum dots (QDs) as the signal amplifying nano-platforms. Owing to the small size, high surface-to-volume ratio and good conductivity, quantum dots were immobilized on the electrode surface for signal amplification...
December 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Xiaojiao Du, Ding Jiang, Nan Hao, Jing Qian, Liming Dai, Lei Zhou, Jianping Hu, Kun Wang
The development of novel detection methodologies in electrochemiluminescence (ECL) aptasensor fields with simplicity and ultrasensitivity is essential for constructing biosensing architectures. Herein, a facile, specific, and sensitive methodology was developed unprecedentedly for quantitative detection of microcystin-LR (MC-LR) based on three-dimensional boron and nitrogen codoped graphene hydrogels (BN-GHs) assisted steric hindrance amplifying effect between the aptamer and target analytes. The recognition reaction was monitored by quartz crystal microbalance (QCM) to validate the possible steric hindrance effect...
October 4, 2016: Analytical Chemistry
Jessica T Wen, Karen Bohorquez, Hideaki Tsutsui
We report a new polydiacetylene (PDA) sensor strip for simple visual detection of zinc ions in aqueous solution. The specificity of this sensor comes from Zn(2+) DNA aptamer probes conjugated onto PDA. Effects of aptamer length and structure on the sensitivity of PDA's color transition were first investigated. PDA conjugated with the optimal aptamer sequence was then coated onto a strip of polyvinylidene fluoride membrane and photopolymerized by UV exposure. The newly developed sensor successfully exhibited a blue-to-red chromatic change in a semi-quantitative manner in response to zinc ions...
September 2016: Sensors and Actuators. B, Chemical
Yingying Qi, Fu-Rong Xiu, Gending Yu, Lili Huang, Baoxin Li
Detection of ultralow concentration of heavy metal ion Hg(2+) is important for human health protection and environment monitoring because of the gradual accumulation in environmental and biological fields. Herein, we report a convenient chemiluminescence (CL) biosensing platform for ultrasensitive Hg(2+) detection by signal amplification mechanism from positively charged gold nanoparticles ((+)AuNPs). It is based on (+)AuNPs charge effect and aptamer conformation change induced by target to stimulate the generation of CL in the presence of H2O2 and luminol without high salt medium...
August 9, 2016: Biosensors & Bioelectronics
Na Bin, Weili Li, Xuehua Yin, Xiaohua Huang, Qingyun Cai
A novel electrochemiluminescence (ECL) aptasensor was proposed for ultrasensitive detection of cytochrome c (cyt c) using CdS:Mn quantum dot-modified TiO2 nanowires (NWs) as electrode. The Mn-doped CdS was deposited on the TiO2 NWs by successive ion layer adsorption and reaction (SILAR) as ECL emitter, on which thiol-modified aptamer of cyt c was attached via Cd-S bond. Due to the high photo-electrical transfer efficiency, the as-prepared aptasensor shows high selectivity and sensitivity towards cyt c with a detection limit of 9...
November 1, 2016: Talanta
Su Liu, Yu Wang, Wei Xu, Xueqi Leng, Hongzhi Wang, Yuna Guo, Jiadong Huang
In this paper, a novel sandwich-type electrochemical aptasensor has been fabricated and applied for sensitive and selective detection of antibiotic oxytetracycline (OTC). This sensor was based on graphene-three dimensional nanostructure gold nanocomposite (GR-3D Au) and aptamer-AuNPs-horseradish peroxidase (aptamer-AuNPs-HRP) nanoprobes as signal amplification. Firstly, GR-3D Au film was modified on glassy carbon electrode only by one-step electrochemical coreduction with graphite oxide (GO) and HAuCl4 at cathodic potentials, which enhanced the electron transfer and loading capacity of biomolecules...
August 6, 2016: Biosensors & Bioelectronics
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