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Wenna Duan, Xiuzhong Wang, Haixia Wang, Feng Li
Since the lack of detection diversity of the single-signal readout strategy, it is urgent to develop fast and multisignal assay strategies. A highly selective and sensitive assay method with colorimetric and fluorometric dual signals readouts is presented in this paper. It is based on the principle that the target induced conjunction of split aptamer fragments assembled on the surface of Au nanoparticles (AuNPs). In the presence of targets, the color of solution changed from wine red to blue and can be measured both visual inspection and spectrophotometry because of the aggregation of AuNPs...
April 1, 2018: Talanta
Li-Ping Jia, Li-Juan Wang, Rong-Na Ma, Lei Shang, Wei Zhang, Qing-Wang Xue, Huai-Sheng Wang
In the present work a highly sensitive and selective aptasensor was developed for the determination of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) based on the hybridization chain reaction (HCR) signal amplification. It was observed that the aptamer of 8-OH-dG could hybridize with the capture DNA immobilized on the gold electrode with a sticky tail left, which initiated the HCR and led to the formation of extended dsDNA structure on the electrode surface. Then the electroactive species ([Ru(NH3)6]3+, RuHex) intercalated into the dsDNA grooves to generate the amplified signal...
March 1, 2018: Talanta
Shengfeng Huang, Ning Gan, Tianhua Li, You Zhou, Yuting Cao, Youren Dong
An ultrasensitive electrochemical aptasensor for multiplex antibiotics detection based on endonuclease and exonuclease assisted dual recycling amplification strategy was proposed. Kanamycin and chloramphenicol were selected as candidates. Firstly, aptamers of the antibiotics were immobilized on bar A and then binding with their endonuclease labeled complementary DNA strands to construct enzyme-cleavage probes. Secondly, The nano zirconium-metal organic framework (NMOF) particles with 1,4-benzene-dicarboxylate (BDC) as linker was defined as UiO-66...
March 1, 2018: Talanta
Cuiying Lin, Huixia Zheng, Mi Sun, Yajuan Guo, Fang Luo, Longhua Guo, Bin Qiu, Zhenyu Lin, Guonan Chen
A simple, low-cost, and sensitive liposome-based colorimetric aptasensor has been developed to detect ochratoxin A (OTA). Specifically, a dumbbell-shaped probe was designed, including magnetic beads (MBs), double-stranded DNA (dsDNA), and enzyme-encapsulated liposome. The dsDNA formed by the hybridization between OTA aptamer and its complementary probe. And the dsDNA was used to contact the MBs and the enzyme-encapsulated liposome. In the presence of OTA, the aptamer preferred to combine with OTA to form G-quadruplex, resulting in the release of the detection probe and the enzyme-encapsulated liposome...
March 9, 2018: Analytica Chimica Acta
Rajni Bala, Anuradha Swami, Ilja Tabujew, Kalina Peneva, Nishima Wangoo, Rohit K Sharma
A novel detection platform with high malathion specificity has been developed, which operates based on the signal response in the fluorescence of CdTe@CdS quantum dots (QDs). The designed nanoprobe comprises of QDs, poly(N-(3-guanidinopropyl)methacrylamide) homopolymer (PGPMA) and malathion specific aptamer. The interaction of aptamer with malathion results in switching off of the fluorescence signal of the probe due to the availability of the cationic polymer, which causes quenching of the QDs. However, in the absence of malathion, the polymer interacts with the aptamer, via electrostatic interactions thereby rendering the fluorescence of QDs unaffected...
December 22, 2017: Biosensors & Bioelectronics
Bushra Jamil, Muhammad Ali Syed
Tremendous efforts through dedicated research have been made for the development of robust, point of care, portable, cost effective, sensitive and specific assays of microbial detection for a wide range of applications. Biosensing and nanotechnology offer novel strategies of designing state of the art devices and assay formats with enhanced sensitivity and all other desired features. Monoclonal antibodies have been in use as biorecognition elements for decades. However, recent studies have demonstrated superiority of aptamers to monoclonal antibodies in a number of applications...
January 4, 2018: Current Drug Targets
Chunyan Deng, Hui Liu, Manman Zhang, Honghua Deng, Chunyang Lei, Lu Shen, Bin Jiao, Qiuyun Tu, Yan Jin, Lei Xiang, Wei Deng, Yongfan Xie, Juan Xiang
Herein, a light-up non-thiolated aptasensor was developed for low-mass soluble amyloid-β40 oligomers (LS-Aβ40-O). Au nanoparticle (AuNP) was employed as a colorimetric probe, and the non-thiolated aptamer (Apt) was adsorbed on AuNP surfaces, acting as a binding element for LS-Aβ40-O. The aggregation of AuNPs was induced when Apt-modified AuNPs (Apt@AuNPs) were under high salt conditions. However, upon addition of LS-Aβ40-O into the Apt@AuNP solution, the salt-tolerance of AuNPs was greatly enhanced. Further studies confirmed that the formed LS-Aβ40-O/Apt complex was attached onto AuNP surfaces via the interaction between LS-Aβ40-O and Au, which led to the electrostatic and steric stabilization of AuNPs under high salt conditions...
January 4, 2018: Analytical Chemistry
Jingyi Luo, Danfeng Jiang, Tao Liu, Jingmeng Peng, Zhenyu Chu, Wanqin Jin
In this work, a novel sandwich-type aptasensor was designed for the ultrasensitive recognition of trace mercury ions in water. Numerous oriented platinum nanotube arrays (PtNAs) were in-situ crystallized on a flexible electrode as a sensing interface, while thionine labelled Fe3O4/rGO nanocomposites as signal amplifiers. Both PtNAs/CF and nanocomposites were synthesized by easy hydrothermal processes. With their large surface area, it was favorable for electrochemical performance and immobilization of capture DNAs (cDNA) and report DNAs (rDNA)...
December 27, 2017: Biosensors & Bioelectronics
Samira Mansouri Majd, Abdollah Salimi
The development of a novel flexible and ultrasensitive aptasensor based on carboxylated multiwalled carbon nanotubes (MWCNTs)/ reduced graphene oxide-based field effect transistor (FET) has been reported for label-free detection of the ovarian cancer antigen (CA125). The fabricated sensor has a straightforward design based on the noncovalent attachment of MWCNTs/aptamer conjugated onto few layers reduced graphene oxide nanosheets and its integration with poly-methyl methacrylate (PMMA) as a suitable platform for designing flexible field-effect transistors...
February 13, 2018: Analytica Chimica Acta
Jiuying Tian, Wenqi Wei, Jiawen Wang, Saijie Ji, Guichan Chen, Jusheng Lu
In the present work, colloidal cerium oxide nanoparticles (nanoceria) and graphene quantum dots (GQDs) were firstly synthesized by sol-gel method and pyrolysis respectively, which all have a uniform nano-size and significant fluorescence emission. Due to the fluorescence emission spectrum of nanoceria overlapped the absorption spectrum of GQDs, fluorescence resonance energy transfer (FRET) between nanoceria and GQDs could occur effectively by the electrostatic interaction. Based on it, a sensitive ratiometric fluorescence aptasensor for the determination of ochratoxin A (OTA), a small molecular mycotoxin produced by Aspergillus and Penicillium strains, has been successfully constructed...
February 13, 2018: Analytica Chimica Acta
Jiayun Hu, Kaiyu Fu, Paul W Bohn
The detection of whole-cell Pseudomonas aeruginosa presents an intriguing challenge with direct applications in health care and the prevention of nosocomial infection. To address this problem, a localized surface plasmon resonance (LSPR) based sensing platform was developed to detect whole-cell Pseudomonas aeruginosa strain PAO1 using a surface-confined aptamer as an affinity reagent. Nanosphere lithography (NSL) was used to fabricate a sensor surface containing a hexagonal array of Au nanotriangles. The sensor surface was subsequently modified with biotinylated polyethylene glycol (Bt-PEG) thiol/ PEG thiol (1:3), neutravidin, and biotinylated aptamer in a sandwich format...
December 20, 2017: Analytical Chemistry
Xiaofan Yu, Fang Chen, Ronghui Wang, Yanbin Li
The rapid detection of foodborne pathogens is critical to ensure food safety. The objective of this study is to select aptamers specifically bound to Escherichia coli O157:H7 using the whole-bacterium SELEX (Systematic Evolution of Ligands by Exponential Enrichment) and apply the selected aptamer to a QCM (quartz crystal microbalance) sensor for rapid and sensitive detection of target bacteria. A total of 19 rounds of selection against live E. coli O157:H7 and 6 rounds of counter selection against a mixture of Staphylococcus aureus, Listeria monocytogenes, and Salmonella Typhimurium, were performed...
December 12, 2017: Journal of Biotechnology
Xiaosong Chen, Jianming Lan, Yingxin Liu, Li Li, Liu Yan, Yaokun Xia, Fang Wu, Chunyan Li, Shirong Li, Jinghua Chen
Exosomes, as potential cancer diagnostic markers have received close attention in recent years. However, there is still a lack of simple and convenient methods to detect and quantitate exosomes. Herein, we used a simple paper-supported aptasensor based on luminescence resonance energy transfer (LRET) from upconversion nanoparticles (UCNPs) to gold nanorods (Au NRs) for the accessible determination of exosomes. When exosomes are present, the two sections of the aptamer can combine with the CD63 protein on the surface of exosomes and form a conjugation to close the distance between UCNPs and Au NRs, which initiates the LRET and promotes luminescence quenching...
December 8, 2017: Biosensors & Bioelectronics
Alisha Geldert, Kenry, Chwee Teck Lim
There has been growing interest in the development of paper-based biosensors because their simplicity and low cost are attractive for point-of-care diagnosis, especially in low-resource areas. However, only a limited range of paper materials - primarily chromatography papers - have been incorporated into diagnostics thus far. Here, we investigate the performance of different types of paper in order to develop an aptamer- and MoS2 nanosheet-based sensor relying on fluorescence resonance energy transfer (FRET) to signal the presence of a target protein...
December 13, 2017: Scientific Reports
Alian Wang, Xiaoming Ma, Yanzhu Ye, Fang Luo, Longhua Guo, Bin Qiu, Zhenyu Lin, Guonan Chen
Electronic balance, one of the most common equipments in the laboratory, is normally adopted to directly measure the weight of the target with high accuracy, however little attention has been paid on the extension of its application. In this study, electronic balance was used as readout to develop a novel aptasensor for protein quantification for the first time. Thrombin was selected as a model target and its two aptamers recognizing different sites of the protein were used (one aptamer was immobilized on the surface of magnetic microparticles and the other aptamer was functionalized with platinum nanoparticles)...
December 12, 2017: Analytical Chemistry
Amit Kumar Pandey, Yudhishthir Singh Rajput, Rajan Sharma, Dheer Singh
An electrochemical aptasensor for detection of trace amounts of aflatoxin M1 was developed. This required immobilization of aptamer on screen printed gold electrode comprising of working electrode, counter electrode and reference electrode and was achieved by sequentially layering dithiodipropionic acid, streptavidin and biotinylated-tetraethylene glycol-aptamer. Immobilization of aptamer was monitored by cyclic voltammetry. Peak current in square wave voltammogram was inversely related to logarithmic concentration of aflatoxin M1...
2017: Applied Nanoscience
Zhenzhen Li, Changjiang Su, Dan Wu, Zhonghai Zhang
Photoelectrochemical aptasensor (PECAS) is a new and promising detection platform with both high sensitivity and good selectivity. Exploration of new photoelectrode materials and establishment of effective charge transfer channel between photoelectrode and aptamer are the main challenges in this field. In this work, an efficient PECAS based on Au nanoparticles (NPs) decorated Fe2O3 nanorod photoelectrode is rationally designed, fabricated, and exhibited excellent sensitivity and selectivity for detection of lysozyme (Lys) with an ultralow detection limit of 3 pM and wide detection range from 10 pM to 100 nM...
December 6, 2017: Analytical Chemistry
Eun-Jung Jo, Ju-Young Byun, Hyoyoung Mun, Doyeon Bang, Jun Ho Son, Jae Young Lee, Luke P Lee, Min-Gon Kim
Contamination of foods by mycotoxins is a common yet serious problem. Owing to the increase in consumption of fresh produce, consumers have become aware of food safety issues caused by mycotoxins. Therefore, rapid and sensitive mycotoxin detection is in great demand in fields such as food safety and public health. Here, we report a single-step luminescence resonance energy transfer (LRET) aptasensor for mycotoxin detection. In order to accomplish the single-step sensor, our sensor was constructed by linking a quencher labeled aptamer through a linker to the surface of upconversion nanoparticles (UCNPs)...
December 6, 2017: Analytical Chemistry
Shunbi Xie, Ying Tang, Dianyong Tang
Traditionally, genomic DNA detection is relay on a rigorous DNA amplification process, which always accompanied with complicated gel electrophoresis or expensive fluorescence detection methods. In this work, we have translated genomic DNA detection into adenosine triphosphate (ATP) test based on a split aptamer-based electrochemical sandwich assay. The key characteristic of our method are list as follows: first, nucleic acid amplification of the target gene was performed by the use of a loop mediated isothermal amplification (LAMP) process...
December 1, 2017: Biosensors & Bioelectronics
Nicole Bahner, Peggy Reich, Dieter Frense, Marcus Menger, Katharina Schieke, Dieter Beckmann
An aptamer-based biosensor was developed for the detection of doxorubicin using electrochemical impedance spectroscopy. Doxorubicin and its 14-dehydroxylated version daunorubicin are anthracyclines often used in cancer treatment. Due to their mutagenic and cardiotoxic effects, detection in groundwater is desirable. We developed a biosensor using the daunorubicin-binding aptamer as biological recognition element. The aptamer was successfully co-immobilized with mercaptohexanol on gold and a density of 1.3*1013 ± 2...
December 3, 2017: Analytical and Bioanalytical Chemistry
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