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Zahra Shekari, Hamid R Zare, Ali Falahati
The present study aims at the fabrication of a novel electrochemical aptasensor, Ap-GA-AMSN-G, for the label-free determination of hemin and hemoglobin (Hb). Basically, the electrochemical reduction current of hemin or Hb incubated on Ap-GA-AMSN-GCE in the presence of oxygen serves as an excellent signal for quantitative determination of these analytes. By differential pulse voltammetry, the calibration plot was linear in the concentration range of 1.0 × 10(-19)-1.0 × 10(-6) M of hemin and Hb. Also, the detection limits, DL, of hemin and Hb were found to be 7...
November 27, 2016: Analytical Biochemistry
Jiajia Lv, Sen Zhao, Shijia Wu, Zhouping Wang
Water safety is one of the most pervasive problems afflicting people throughout the world. Microcystin-LR (MC-LR), a representative toxin released by cyanobacteria, poses an increasing and serious threat to water safety. In order to develop facile, specific and sensitive detection methods for MC-LR, we fabricated an ultrasensitive fluorescence aptasensor using the enhanced fluorescence of UCNP and the effective quenching ability, high affinity toward single strand DNA (ssDNA) of MoS2 (termed as FAUM). This assay specifically determined MC-LR in the linear range of 0...
October 4, 2016: Biosensors & Bioelectronics
Aixue Li, Jian Zhang, Jichuan Qiu, Zhenhuan Zhao, Cheng Wang, Chunjiang Zhao, Hong Liu
It has been reported that tungsten disulfide (WS2) can bind single-stranded DNA (ssDNA) with high affinity while it has less affinity toward double stranded DNA (dsDNA). In this work, for the first time, the high affinity between WS2 and ssDNA was used to construct stable sensing interface for ATP detection. A DNA sequence with -SH at one end was first immobilized on Au electrode. WS2 nanosheets were immobilized on the SH-DNA/Au electrode surface due to the strong affinity between WS2 and ssDNA. Then the WS2 nanosheets were used to immobilize ATP binding aptamer (ABA) through the high affinity between WS2 and ssDNA, too...
January 15, 2017: Talanta
Tianhong Lou, Hong Qiang, Zhengbo Chen
A growing body of evidence indicates that lysozyme plays a significant role as an indicator for many diseases and a drug for treatment of infections, ulcers and to study the spatial conformation, enzyme kinetics, and molecular immunology. Therefore, highly sensitive determination of lysozyme is necessary and vital in a wide variety of fields. In this work, we put forward a simple but effective strategy for colorimetric visualization of lysozyme based on iodide-responsive Cu@Au nanoparticles (Cu@Au NPs) as well as the iodide-catalyzed H2O2-TMB (3,3,5,5-tetramethylbenzidine) reaction system...
January 15, 2017: Talanta
Harriet Khang, Kelly Cho, Stephanie Chong, Ji Hoon Lee
Using a dual DNA aptamer (CEA aptamer linked to hemin aptamer), capable of rapidly capturing carcinoembryonic antigen (CEA) and hemin, an all-in-one dual-aptasensor with 1,1'-oxalyldiimidazole (ODI) chemiluminescence detection was developed for the early diagnosis of human cancer. CEA and hemin competitively bound with the dual DNA aptamer while the mixture in a detection cell was incubated for 30min at room temperature. When Amplex Red and H2O2 were added in the detection cell after the incubation, the yield of resorufin formed from the reaction Amplex Red and H2O2 depended on the concentration of HRP-mimicking G-quardruplex DNAzyme formed from the binding interaction between hemin and the dual DNA aptamer...
November 16, 2016: Biosensors & Bioelectronics
Zhihong Zhang, Chuanpan Guo, Shuai Zhang, Linghao He, Minghua Wang, Donglai Peng, Junfeng Tian, Shaoming Fang
We synthesized two kinds of carbon-based nanocomposites of silver nanoclusters (AgNCs). An aptamer for targeted platelet-derived growth factor-BB (PDGF-BB) detection was used as the organic phase to produce AgNCs@Apt, three dimensional reduced graphene oxide@AgNCs@Aptamer (3D-rGO@AgNCs@Apt), and graphene quantum dots@AgNCs@Aptamer (GQD@AgNCs@Apt) nanocomposites. The formation mechanism of the developed nanocomposites was described by detailed characterizations of their chemical and crystal structures. Subsequently, the as-synthesized nanoclusters containing aptamer strands were applied as the sensitive layers to fabricate a novel electrochemical aptasensor for the detection of PDGF-BB, which may be directly used to determine the target protein...
November 12, 2016: Biosensors & Bioelectronics
Lanlan Wang, Rongna Ma, Liushan Jiang, Liping Jia, Wenli Jia, Huaisheng Wang
A novel dual-signal ratiometric electrochemical aptasensor for highly sensitive and selective detection of thrombin has been designed on the basis of signal-on and signal-off strategy. Ferrocene labeled hairpin probe (Fc-HP), thrombin aptamer and methyl blue labeled bio-bar-coded AuNPs (MB-P3-AuNPs) were rationally introduced for the construction of the assay platform, which combined the advantages of the recognition of aptamer, the amplification of bio-bar-coded nanoprobe, and the ratiometric signaling readout...
November 1, 2016: Biosensors & Bioelectronics
Huifeng Xu, Shijing Liang, Xi Zhu, Xiuqin Wu, Yongqiang Dong, Haishan Wu, Wenxia Zhang, Yuwu Chi
A novel g-C3N4 nanosheets embedded with C3N4 QDs nanocomposites (QD@CNNS) was prepared by simple oxidation using hydrogen peroxide and UV light irradiation. This nanocomposite exhibits more stable and stronger electrochemiluminescent (ECL) behavior compared with CNNS. Coupling this nanocomposite with Fc-labeled aptamer, a signal-on aptasensor for platelet derived growth factor BB (PDGF-BB) is fabricated. Initially, the Fc-labeled aptamer binds onto QD@CNNS via π-π conjugation and electrostatic interaction, quenching ECL emission from QD@CNNS...
October 14, 2016: Biosensors & Bioelectronics
Ayemeh Bagheri Hashkavayi, Jahan Bakhsh Raoof, Reza Ojani, Saeid Kavoosian
Colorectal cancer is one of the most common cancers in the world and has no effective treatment. Therefore, development of new methods for early diagnosis is instantly required. Biological recognition probes such as synthetic receptor and aptamer is one of the candidate recognition layers to detect important biomolecules. In this work, an electrochemical aptasensor was developed by fabricating an aptamer-cell-aptamer sandwich architecture on an SBA-15-3-aminopropyltriethoxysilane (SBA-15-pr-NH2) and Au nanoparticles (AuNPs) modified graphite screen printed electrode (GSPE) surface for the selective, label-free detection of CT26 cancer cells...
October 19, 2016: Biosensors & Bioelectronics
Fengping Zhan, Xiaolei Liao, Feng Gao, Weiwei Qiu, Qingxiang Wang
A novel electrochemical DNA biosensor has been facilely constructed by in-situ assembly of electroactive 4'-aminobenzo-18-crown-6-copper(II) complex (AbC-Cu(2+)) on the free terminal of the hairpin-structured molecule beacon. The 3'-SH modified molecule beacon probe was first immobilized on the gold electrode (AuE) surface through self-assembly chemistry of Au-S bond. Then the crow ester of AbC was covalently coupled with 5'-COOH on the molecule beacon, and served as a platform to attach the Cu(2+) by coordination with ether bond (-O-) of the crown cycle...
October 21, 2016: Biosensors & Bioelectronics
Birui Jin, Shurui Wang, Min Lin, Ying Jin, Shujing Zhang, Xingye Cui, Yan Gong, Ang Li, Feng Xu, Tian Jian Lu
Pathogenic bacteria cause serious harm to human health, which calls for the development of advanced detection methods. Herein, we developed a novel detection platform based on fluorescence resonance energy transfer (FRET) for rapid, ultrasensitive and specific bacteria detection, where gold nanoparticles (AuNPs, acceptor) were conjugated with aptamers while upconversion nanoparticles (UCNPs, donor) were functionalized with corresponding complementary DNA (cDNA). The spectral overlap between UCNPs fluorescence emission and AuNPs absorption enables the occurrence of FRET when hybridizing the targeted aptamer and cDNA, causing upconversion fluorescence quenching...
October 19, 2016: Biosensors & Bioelectronics
Sajal Shrivastava, Nguyen Minh Triet, Young-Min Son, Won-Il Lee, Nae-Eung Lee
Probe-mediated fluorescence biosensing methods based on spectrophotometry still have limitations such as detection inaccuracy caused by the occurrence of false signals and lack of simultaneous qualitative and quantitative read-outs with an ultra-low detection limit. Herein, we describe a novel seesawed fluorescence detection strategy based on dual-colour imaging-based quantitation in which the green fluorescence of the capture aptamer decreases and the red fluorescence of the detection aptamer increases simultaneously upon their respective interactions with the target biomolecule...
September 26, 2016: Biosensors & Bioelectronics
Zhuangqiang Gao, Zhenli Qiu, Minghua Lu, Jian Shu, Dianping Tang
This work designs a new label-free aptasensor for the colorimetric determination of small molecules (adenosine 5'-triphosphate, ATP) by using visible gold nanoparticles as the signal-generation tags, based on target-triggered hybridization chain reaction (HCR) between two hairpin DNA probes. The assay is carried out referring to the change in the color/absorbance by salt-induced aggregation of gold nanoparticles after the interaction with hairpins, gold nanoparticles and ATP. To construct such an assay system, two hairpin DNA probes with a short single-stranded DNA at the sticky end are utilized for interaction with gold nanoparticles...
October 20, 2016: Biosensors & Bioelectronics
Guangming Zeng, Chen Zhang, Danlian Huang, Cui Lai, Lin Tang, Yaoyu Zhou, Piao Xu, Hou Wang, Lei Qin, Min Cheng
A simple, practical and reusable electrochemical aptasensor, based on thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and nanoporous gold (NPG) for signal amplification, was designed for sensitive and selective detection of mercury ions (Hg(2+)). The thiol modified T-rich hairpin capture probe was self-assembled onto the surface of the NPG modified electrode for hybridizing with ferrocene-labeled T-rich probe in the presence of Hg(2+) via T-Hg(2+)-T coordination chemistry. As a result, the hairpin capture probe was opened, and the ferrocene tags were close to the NPG modified electrode...
October 7, 2016: Biosensors & Bioelectronics
Hadi Mirzajani, Cheng Cheng, Jayne Wu, Jiangang Chen, Shigotoshi Eda, Esmaeil Najafi Aghdam, Habib Badri Ghavifekr
A rapid, highly sensitive, specific and low-cost capacitive affinity biosensor is presented here for label-free and single step detection of Bisphenol A (BPA). The sensor design allows rapid prototyping at low-cost using printed circuit board material by benchtop equipment. High sensitivity detection is achieved through the use of a BPA-specific aptamer as probe molecule and large electrodes to enhance AC-electroelectrothermal effect for long-range transport of BPA molecules toward electrode surface. Capacitive sensing technique is used to determine the bounded BPA level by measuring the sample/electrode interfacial capacitance of the sensor...
October 4, 2016: Biosensors & Bioelectronics
Jing-Jing Zhang, Fang-Fang Cheng, Ting-Ting Zheng, Jun-Jie Zhu
Quantifying the glycan expression status on cell surfaces is of vital importance for insight into the glycan function in biological processes and related diseases. Here we developed a versatile aptasensor for electrochemical quantification of cell surface glycan by taking advantage of the cell-specific aptamer, and the lectin-functionalized gold nanoparticles acting as both a glycan recognition unit and a signal amplification probe. To construct the aptasensor, amine-functionalized mucin 1 protein (MUC1) aptamer was first covalently conjugated to carboxylated-magnetic beads (MBs) using the succinimide coupling (EDC-NHS) method...
September 25, 2016: Biosensors & Bioelectronics
Junlong Li, Kexin Sun, Zhongping Chen, Jifei Shi, Dandan Zhou, Guoming Xie
Vascular endothelial growth factor (VEGF) is an important biomarker in cancer angiogenesis. Here, we develop a aptasensor method for VEGF detection based on DNA assembly structure switching and isothermal amplification. The design employs a DNA assembly made of a isothermal amplification template, a aptamer, a primer and a protector chain. The DNA assembly is unable to undergo isothermal amplification in the absence of target. The presence of the target, however, triggers a structure switching event that causes hybridization of primer with template to facilitate isothermal amplification...
September 30, 2016: Biosensors & Bioelectronics
Wentao Xu, Jingjing Tian, Xiangli Shao, Longjiao Zhu, Kunlun Huang, Yunbo Luo
For previously reported aptasensor, the sensitivity and selectivity of aptamers to targets were often suppressed due to the reporter label of single-stranded molecular beacon or hindrance of the duplex DNA strand displacement. To solve the affinity declining of aptamers showed in traditional way and realize on-site rapid detection of Lipopolysaccharides (LPS), we developed an ingenious structure-switching aptasensor based on the bulb-like triplex turn-on switch (BTTS) as the effective molecular recognition and signal transduction element and streptavidin-horseradish peroxidase modified hybridization chain reaction (HCR-HRP) nanocomposites as the signal amplifier and signal report element...
October 5, 2016: Biosensors & Bioelectronics
Chengquan Wang, Jing Qian, Keqi An, Xingyi Huang, Lufang Zhao, Qian Liu, Nan Hao, Kun Wang
Currently there is an urgent need for multi-mycotoxin detection methods due to the co-occurrence of multiple mycotoxins in food raw materials and their augmented toxicity. Herein, a magneto-controlled aptasensor has been developed for simultaneous electrochemical detection of ochratoxin A (OTA) and fumonisin B1 (FB1), two typical mycotoxins found in food crops world-wide. This aptasensor was designed using the high specificity between the target and aptamer with heavy CdTe or PbS quantum dots (QDs) coated silica as labels and the complementary DNA functionalized magnetic beads as capture probes...
October 4, 2016: Biosensors & Bioelectronics
Jinquan Liu, Dinggeng He, Qiaoqiao Liu, Xiaoxiao He, Kemin Wang, Xue Yang, Jingfang Shangguan, Jinlu Tang, Yinfei Mao
Herein, a simple, facile and label-free electrochemiluminescence (ECL) aptasensor platform was constructed by integration of aptamer-gated systems and vertically ordered mesoporous silica films (MSFs) grown in suit of indium-tin oxide (ITO) electrode. In this aptasensor platform, aptamer could be effectively adsorbed on the surface of aminated MSFs by non-covalent electrostatic attraction and then employed as an ideal gate material to control the blocking and releasing of luminescence reagents (Ru(bipy)32+) entrapped within the pores of MSFs...
November 3, 2016: Analytical Chemistry
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