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Falan Li, Yemin Guo, Xiangyou Wang, Xia Sun
A dual-target electrochemical aptasensor was developed for the simultaneous detection of multiple antibiotics based on metal ions as signal tracers and nanocomposites as signal amplification strategy. Metal ions such as Cd2+ and Pb2+ could generate distinct differential pulse voltammetry (DPV) peaks. When targets were present, kanamycin (KAN) and streptomycin (STR) as models, the KAN aptamer (KAP) and STR aptamer (STP) were released from their complementary strands, with more change of Cd2+ and Pb2+ corresponding to peak currents...
April 13, 2018: Biosensors & Bioelectronics
Xin Zhang, Ning Bao, Xiliang Luo, Shou-Nian Ding
In this work, novel multifunctional patchy gold coated Fe3 O4 hybrid nanoparticles (PG-Fe3 O4 NPs) have been successfully synthesized in aqueous medium via a facile adsorption-reduction method. A rational formation mechanism has been proposed by monitoring the morphological evolution. The PG-Fe3 O4 NPs retained the good magnetic property and exhibited excellent catalytical effeciency towards the electrochemical reduction of hydrogen peroxide. Chronoamperometric and amperometric experiments indicated a relatively high catalytic rate constant of 3...
May 10, 2018: Biosensors & Bioelectronics
Mohammad Hasanzadeh, Amir Zargami, Hossein Navay Baghban, Ahad Mokhtarzadeh, Nasrin Shadjou, Soltanali Mahboob
The genetic disorder phenylketonuria (PKU) is the inability to metabolize phenylalanine because of a lack of the enzyme phenylalanine hydroxylase. Phenylalanine is used to biochemically form proteins, coded for by DNA. The development of an apta-assay for detection of l-Phenylalanine is presented in this work. A highly specific DNA-aptamer, selected to l-Phenylalanine was immobilized onto a gold nanostructure and electrochemical measurements were performed in a solution containing the phosphate buffer solution with physiological pH...
May 16, 2018: International Journal of Biological Macromolecules
Nuo Duan, Shijia Wu, Huiling Zhang, Ying Zou, Zhouping Wang
An F0 F1 -ATPase-based aptasensor is described for the fluorometric determination of Vibrio parahaemolyticus. Chromatophores containing F0 F1 -ATPases were first prepared from Rhodospirillum rubrum cells. Then, an aptamer-functionalized chromatophore acts as the capture probe, and a chromatophore labeled with the pH probe fluorescein acts as the signalling probe. In the presence of V. parahaemolyticus, the rotation rate of F0 F1 -ATPase is decreased due to the formation of the aptamer-chromatophore complex...
May 18, 2018: Mikrochimica Acta
Chong Cheen Ong, Subash C B Gopinath, Leong Wei Xian Rebecca, Veeradasan Perumal, Thangavel Lakshmipriya, Mohamed Shuaib Mohamed Saheed
There are different clotting factors present in blood, carries the clotting cascade and excessive bleeding may cause a deficiency in the clotting. Diagnosis of deficiency in clotting reduces the potential fatality. For enabling a sensor to detect the clotting factors, suitable probes such as antibody and aptamer have been used to capture the clotting factors on the sensing surface. Two major clotting factors were widely studied in detail for the diagnosis of clotting deficiency, which includes factor IX and thrombin...
May 15, 2018: International Journal of Biological Macromolecules
Zeinab Saberi, Behzad Rezaei, Hossein Faroukhpour, Ali Ashghar Ensafi
Cobalt oxyhydroxide (CoOOH) nanosheets are efficient fluorescence quenchers due to their specific optical properties and high surface area. The combination of CoOOH nanosheets and carbon dots (CDs) has not been used in any aptasensor based on fluorescence quenching so far. An aptamer based fluorometric assay is introduced that is making use of fluorescent CDs conjugated to the aptamer against methamphetamine (MTA), and of CoOOH nanosheets which reduce the fluorescence of the CDs as a quencher. The results revealed that the conjugated CDs with aptamers were able to enclose the CoOOH nanosheets...
May 17, 2018: Mikrochimica Acta
H Zejli, K Yugender Goud, Jean Louis Marty
This work demonstrates the development of electrochemical aptasensor using ochratoxin A (OTA) aptamers. Different aptamer coupling strategies were tested using polythiophene-carboxylic acid (PT3C) and polypyrrole-3-carboxylic acid (PP3C). The best sensitivity was recorded by polythiophene-3-carboxylic acid (PT3C) on screen-printed carbon electrode (SPCE) to attain the direct detection of OTA. The quantification of OTA was achieved by using electrochemical impedance spectroscopy. A good dynamic range 0.125-2...
August 1, 2018: Talanta
Yan Wu, Tingting Jiang, Zhaoyang Wu, Ruqin Yu
A ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods was proposed for the ultrasensitive and reproducible quantitative detection of silver ion (Ag+ ) with Au@Ag core-shell nanoparticle (Au@Ag NP) substrate. In principle, the thiolated 5'-Rox C-containing labeled aptamer probe (Rox-aptamer) is firstly immobilized on the SERS substrate surface and then hybridizes with the complementary DNA (cDNA) to form a rigid double-stranded DNA (dsDNA), in which the Rox Raman labels is used to produce the Raman signal...
August 1, 2018: Talanta
Dandan Yang, Mei Liu, Jing Xu, Chao Yang, Xiaoxiao Wang, Yongbing Lou, Nongyue He, Zhifei Wang
In this work, carbon nanosphere (CNS)-based fluorescence "turn off/on" aptasensor was developed for targeted detection of breast cancer cell MCF-7 by conjugation with FAM (a dye)-labeled mucin1 (MUC1) aptamer P0 (P0-FAM), which can recognize MUC1 protein overexpressed on the surface of MCF-7. Different from other carbon based fluorescence quenching materials, CNSs prepared by the carbonization of glucose not only have the high fluorescence quenching efficiency (98.8%), but also possess negligible cytotoxicity (in the concentration range of 0-1 mg/mL, which is 10 times higher than that of traditional carbon nanotubes or graphene oxide (0-100 µg/mL))...
August 1, 2018: Talanta
Xiujuan Qiao, Kunxia Li, Jinqiong Xu, Ni Cheng, Qinglin Sheng, Wei Cao, Tianli Yue, Jianbin Zheng
Cardiac troponin I (cTnI) is a specific and sensitive biomarker for the early diagnosis of acute myocardial infarction and for the subsequent clinical treatments. In this work, novel electrochemical sensing platform for sensing of cTnI based on aptamer-MoS2 nanoconjugates was proposed. For comparison, core-shell Au@SiO2 @Au nanoparticles were also used for sensing of cTnI. The sensing schemes and electrochemical responses of the proposed sensors were investigated by electrochemical impedance spectroscopy (EIS) in 5...
May 4, 2018: Biosensors & Bioelectronics
Abigail J Van Riesen, Kaila L Fadock, Prashant S Deore, Ahmed Desoky, Richard A Manderville, Shahin Sowlati-Hashjin, Stacey D Wetmore
Chemically modified aptamers have the opportunity to increase aptamer target binding affinity and provide structure-activity relationships to enhance our understanding of molecular target recognition by the aptamer fold. In the current study, 8-aryl-2'-deoxyguanosine nucleobases have been inserted into the G-tetrad and central TGT loop of the thrombin binding aptamer (TBA) to determine their impact on antiparallel G-quadruplex (GQ) folding and thrombin binding affinity. The aryl groups attached to the dG nucleobase vary greatly in aryl ring size and impact on GQ stability (∼20 °C change in GQ thermal melting (Tm) values) and thrombin binding affinity (17-fold variation in dissociation constant (Kd))...
May 10, 2018: Organic & Biomolecular Chemistry
Gang Peng, Xiaoyan Li, Feng Cui, Qianying Qiu, Xiaojun Chen, He Huang
In the food safety evaluation, aflatoxin B1 (AFB1) is an important indicator. In this work, we developed an AFB1 electrochemical aptasensor based on tetrahedral DNA nanostructures (TDNs) immobilized three dimensionally ordered macroporous MoS2-AuNPs hybrid (3DOM MoS2-AuNPs) recognition interface and horseradish peroxidase (HRP) functionalized magnetic signal amplifier. To greatly enhance the recognition efficiency, sensitivity and stability of the aptasensor, the AFB1 aptamer-incorporated TDNs were ingeniously combined with the 3DOM MoS2-AuNPs film for the construction of the sensing interface...
May 7, 2018: ACS Applied Materials & Interfaces
Saba Ranjbar, Saeed Shahrokhian
Since that pathogenic bacteria are major threats to human health, this paper describes the fabrication of an effective and durable sensing platform based on gold nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite (AuNPs/CNPs/CNFs) at the surface of glassy carbon electrode for sensitive and selective detection of Staphylococcus aureus (S. aureus). The AuNPs/CNPs/CNFs nanocomposite with the high surface area, excellent conductivity, and good biocompatibility was used for self-assembled of the thiolated specific S...
April 27, 2018: Bioelectrochemistry
Nasrin Razmi, Behzad Baradaran, Maryam Hejazi, Mohammad Hasanzadeh, Jafar Mosafer, Ahad Mokhtarzadeh, Miguel de la Guardia
Platelet-derived growth factor (PDGF-BB), a significant serum cytokine, is an important protein biomarker in diagnosis and recognition of cancer, which straightly rolled in proceeding of various cell transformations, including tumor growth and its development. Fibrosis, atherosclerosis are certain appalling diseases, which PDGF-BB is near to them. Generally, the expression amount of PDGF-BB increases in human life-threatening tumors serving as an indicator for tumor angiogenesis. Thus, identification and quantification of PDGF-BB in biomedical fields are particularly important...
April 22, 2018: Biosensors & Bioelectronics
Dongkui Liu, Xing Lu, Yiwen Yang, Yunyun Zhai, Jian Zhang, Lei Li
Acute myocardial infarction (AMI) is one of the leading risks to global health. Thus, the rapid, accurate early diagnosis of AMI is highly critical. Human cardiac troponin I (cTnI) has been regarded as a golden biomarker for AMI due to its excellent selectivity. In this work, a novel fluorescent aptasensor based on a graphene oxide (GO) platform was developed for the highly sensitive and selective detection of cTnI. GO binds to the fluorescent anti-cTnI aptamer and quenches its fluorescence. In the presence of cTnI, the fluorescent anti-cTnI aptamer leaves the surface of GO, combines with cTnI because of the powerful affinity of the fluorescent anti-cTnI aptamer and cTnI, and then restores the fluorescence of the fluorescent anti-cTnI aptamer...
May 4, 2018: Analytical and Bioanalytical Chemistry
Witthawat Phanchai, Unnop Srikulwong, Apiwat Chompoosor, Chadamas Sakonsinsiri, Theerapong Puangmali
Colorimetric aptasensor based on assembly of salt-induced gold nanoparticles (AuNPs) is a promising biosensor. However, the molecular mechanism of the aptasensor is far from being fully understood. Herein, molecular dynamics (MD) simulation was used to investigate molecular interactions in the detection of ochratoxin A (OTA) including: (i) the molecular recognition of the anti-OTA aptamer, (ii) OTA-aptamer interactions in monovalent (Na+) and divalent (Mg2+) electrolytes, (iii) the binding mode of citrate on the AuNP surface, (iv) interactions of the aptamer with citrate-capped AuNPs and (v) a detailed mechanism of the aptasensor...
May 3, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Zongwen Wang, Haixiang Yu, Juan Canoura, Yingzhu Liu, Obtin Alkhamis, Fengfu Fu, Yi Xiao
We report a broadly applicable enzyme digestion strategy for introducing structure-switching functionality into small-molecule-binding aptamers. This procedure is based on our discovery that exonuclease III (Exo III) digestion of aptamers is greatly inhibited by target binding. As a demonstration, we perform Exo III digestion of a pre-folded three-way-junction (TWJ)-structured cocaine-binding aptamer and a stem-loop-structured ATP-binding aptamer. In the absence of target, Exo III catalyzes 3'-to-5' digestion of both aptamers to form short, single-stranded products...
April 30, 2018: Nucleic Acids Research
Feng Hong, Xixue Chen, Yuting Cao, Youren Dong, Dazhen Wu, Futao Hu, Ning Gan
It is critically important to detect antibiotic residues for monitoring food safety. In this study, an enzyme- and label-free electrochemical aptasensor for antibiotics, with kanamycin (Kana) as a typical analyte, was developed based on a double stir bar-assisted toehold-mediated strand displacement reaction (dSB-TMSDR) for dual-signal amplification. First, we modified two gold electrodes (E-1 and E-2) with different DNA probes (S1/S2 hybrid probe in E-1 and DNA fuel strand S3 in E-2). In the presence of Kana, an S1/S2 probe can be disassembled from E-1 to form an S2/Kana complex in supernatant...
April 9, 2018: Biosensors & Bioelectronics
Minghua Wang, Longyu Yang, Bin Hu, Jiameng Liu, Linghao He, Qiaojuan Jia, Yingpan Song, Zhihong Zhang
We designed and constructed a novel aptasensor based on the porous nanostructured bimetallic NiFe-oxides embedded with the mesoporous carbon (represented by NiOx FeOy @mC) for sensitively detecting adenosine triphosphate (ATP), of which the porous NiOx FeOy @mC was derived from the hollow NiFe Prussian blue analogue (hollow NiFe PBA) by calcinating under high temperature. Owning to the excellent electrochemical activity originated from the metal oxides and mesoporous carbon and the strong binding interaction between the aptamer strands and the nanostructure hybrid, the formed porous NiOx FeOy @mC composite calcinated at 900 °C exhibited superior sensitivity toward ATP determination in comparison with other porous nanocubes obtained at 500 and 700 °C...
April 24, 2018: Biosensors & Bioelectronics
Xiaoqiang Liu, Peipei Liu, Yunfei Tang, Liwei Yang, Lele Li, Zhichong Qi, Deliang Li, Danny K Y Wong
In this work, a sensitive photoelectrochemical aptasensor was developed for kanamycin detection using an enhanced photocurrent response strategy, which is based on the surface plasmon resonance effect of gold nanoparticles deposited on a 3D TiO2 -MoS2 flower-like heterostructure. A significant aspect of this development lies in the photoelectrochemical and morphological features of the unique ternary composite, which have contributed to the excellent performance of the sensor. To develop an aptasensor, mercapto-group modified aptamers were immobilised on the photoactive composite as a recognition unit for kanamycin...
April 19, 2018: Biosensors & Bioelectronics
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