scholarly journals Surface state of the dopamine RNA aptamer affects specific recognition and binding of dopamine by the aptamer-modified electrodes

The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 4089-4096 ◽  
Author(s):  
Isabel Álvarez-Martos ◽  
Rui Campos ◽  
Elena E. Ferapontova
Keyword(s):  
Surface State ◽  
Surface Coverage ◽  
Modified Electrodes ◽  
Rna Aptamer ◽  
Label Free ◽  
Specific Recognition ◽  
Electrochemical Label

An electrochemical label-free aptasensor monitors physiological levels of dopamine with improved sensitivity when the aptamer surface coverage is optimized and with no interference from other catecholamines.

Label-Free Electrochemical Detection of DNA Hybridization Related to Anthrax Lethal Factor by using Carbon Nanotube Modified Sensors

2019 ◽  
Vol 15 (4) ◽  
pp. 502-510 ◽  
Author(s):  
Hakan Karadeniz ◽  
Arzum Erdem
Keyword(s):  
Detection Limit ◽  
Dna Hybridization ◽  
Lethal Factor ◽  
Modified Electrodes ◽  
Label Free ◽  
Carbon Paste ◽  
Chip Technology ◽  
Anthrax Lethal Factor ◽  
Hybridization Time ◽  
Electrochemical Monitoring

Background: Anthrax Lethal Factor (ANT) is the dominant virulence factor produced by B. anthracis and is the major cause of death of infected animals. In this paper, pencil graphite electrodes GE were modified with single-walled and multi-walled carbon nanotubes (CNTs) for the detection of hybridization related to the ANT DNA for the first time in the literature. Methods: The electrochemical monitoring of label-free DNA hybridization related to ANT DNA was explored using both SCNT and MCNT modified PGEs with differential pulse voltammetry (DPV). The performance characteristics of ANT-DNA hybridization on disposable GEs were explored by measuring the guanine signal in terms of optimum analytical conditions; the concentration of SCNT and MCNT, the concentrations of probe and target, and also the hybridization time. Under the optimum conditions, the selectivity of probe modified electrodes was tested and the detection limit was calculated. Results: The selectivity of ANT probes immobilized onto MCNT-GEs was tested in the presence of hybridization of probe with NC no response was observed and with MM, smaller responses were observed in comparison to full-match DNA hybridization case. Even though there are unwanted substituents in the mixture samples containing both the target and NC in the ratio 1:1 and both the target and MM in the ratio 1:1, it has been found that ANT probe immobilized CNT modified graphite sensor can also select its target by resulting with 20.9% decreased response in comparison to the one measured in the case of full-match DNA hybridization case Therefore, it was concluded that the detection of direct DNA hybridization was performed by using MCNT-GEs with an acceptable selectivity. Conclusion: Disposable SCNT/MCNT modified GEs bring some important advantages to our assay including easy use, cost-effectiveness and giving a response in a shorter time compared to unmodified PGE, carbon paste electrode and glassy carbon electrode developed for electrochemical monitoring of DNA hybridization. Consequently, the detection of DNA hybridization related to the ANT DNA by MCNT modified sensors was performed by using lower CNT, probe and target concentrations, in a shorter hybridization time and resulting in a lower detection limit according to the SCNT modified sensors. In conclusion, MCNT modified sensors can yield the possibilities leading to the development of nucleic acid sensors platforms for the improvement of fast and cost-effective detection systems with respect to DNA chip technology.

scholarly journals Ultrasensitive and label free electrochemical immunosensor for detection of ROR1 as an oncofetal biomarker using gold nanoparticles assisted LDH/rGO nanocomposite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rozita Abolhasan ◽  
Balal Khalilzadeh ◽  
Hadi Yousefi ◽  
Sahar Samemaleki ◽  
Forough Chakari-Khiavi ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Flexible Structures ◽  
Modified Electrodes ◽  
Electrochemical Immunosensor ◽  
Lymphocytic Leukemia ◽  
Orphan Receptor ◽  
Detection Sensitivity ◽  
Label Free ◽  
Serum Samples ◽  
Limit Of Quantification

AbstractIn the present article, we developed a highly sensitive label-free electrochemical immunosensor based on NiFe-layered double hydroxides (LDH)/reduced graphene oxide (rGO)/gold nanoparticles modified glassy carbon electrode for the determination of receptor tyrosine kinase-like orphan receptor (ROR)-1. In this electrochemical immunoassay platform, NiFe-LDH/rGO was used due to great electron mobility, high specific surface area and flexible structures, while Au nanoparticles were prepared and coated on the modified electrodes to improve the detection sensitivity and ROR1 antibody immobilizing (ROR1Ab). The modification procedure was approved by using cyclic voltammetry and differential pulse voltammetry based on the response of peak current to the step by step modifications. Under optimum conditions, the experimental results showed that the immunosensor revealed a sensitive response to ROR1 in the range of 0.01–1 pg mL−1, and with a lower limit of quantification of 10 attogram/mL (10 ag mL−1). Furthermore, the designed immunosensor was applied for the analysis of ROR1 in several serum samples of chronic lymphocytic leukemia suffering patients with acceptable results, and it also exhibited good selectivity, reproducibility and stability.

Label-free RNA aptamer-based capacitive biosensor for the detection of C-reactive protein

2010 ◽  
Vol 12 (32) ◽  
pp. 9176 ◽  
Author(s):  
Anjum Qureshi ◽  
Yasar Gurbuz ◽  
Saravan Kallempudi ◽  
Javed H. Niazi
Keyword(s):  
Rna Aptamer ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Capacitive Biosensor

Porous silicon membrane-modified electrodes for label-free voltammetric detection of MS2 bacteriophage

2016 ◽  
Vol 80 ◽  
pp. 47-53 ◽  
Author(s):  
Nekane Reta ◽  
Andrew Michelmore ◽  
Christopher Saint ◽  
Beatriz Prieto-Simón ◽  
Nicolas H. Voelcker
Keyword(s):  
Porous Silicon ◽  
Modified Electrodes ◽  
Label Free ◽  
Silicon Membrane ◽  
Ms2 Bacteriophage ◽  
Voltammetric Detection

Influence of Nanometric Holes on the Sensitivity of a Waveguide-Mode Sensor: Label-Free Nanosensor for the Analysis of RNA Aptamer−Ligand Interactions

2008 ◽  
Vol 80 (17) ◽  
pp. 6602-6609 ◽  
Author(s):  
Subash C. B. Gopinath ◽  
Koichi Awazu ◽  
Makoto Fujimaki ◽  
Katsuaki Sugimoto ◽  
Yoshimichi Ohki ◽  
...  
Keyword(s):  
Waveguide Mode ◽  
Rna Aptamer ◽  
Label Free ◽  
Ligand Interactions

scholarly journals Fluorogenic RNA Aptamers: A Nano-platform for Fabrication of Simple and Combinatorial Logic Gates

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 984 ◽  
Author(s):  
Victoria Goldsworthy ◽  
Geneva LaForce ◽  
Seth Abels ◽  
Emil Khisamutdinov
Keyword(s):  
Rna Binding ◽  
Fluorescent Dyes ◽  
Free Ligand ◽  
Logic Gates ◽  
Boolean Logic ◽  
Rna Aptamers ◽  
Nucleic Acid Detection ◽  
Rna Aptamer ◽  
Label Free ◽  
Half Adder

RNA aptamers that bind non-fluorescent dyes and activate their fluorescence are highly sensitive, nonperturbing, and convenient probes in the field of synthetic biology. These RNA molecules, referred to as light-up aptamers, operate as molecular nanoswitches that alter folding and fluorescence function in response to ligand binding, which is important in biosensing and molecular computing. Herein, we demonstrate a conceptually new generation of smart RNA nano-devices based on malachite green (MG)-binding RNA aptamer, which fluorescence output controlled by addition of short DNA oligonucleotides inputs. Four types of RNA switches possessing AND, OR, NAND, and NOR Boolean logic functions were created in modular form, allowing MG dye binding affinity to be changed by altering 3D conformation of the RNA aptamer. It is essential to develop higher-level logic circuits for the production of multi-task nanodevices for data processing, typically requiring combinatorial logic gates. Therefore, we further designed and synthetized higher-level half adder logic circuit by “in parallel” integration of two logic gates XOR and AND within a single RNA nanoparticle. The design utilizes fluorescence emissions from two different RNA aptamers: MG-binding RNA aptamer (AND gate) and Broccoli RNA aptamer that binds DFHBI dye (XOR gate). All computationally designed RNA devices were synthesized and experimentally tested in vitro. The ability to design smart nanodevices based on RNA binding aptamers offers a new route to engineer “label-free” ligand-sensing regulatory circuits, nucleic acid detection systems, and gene control elements.

scholarly journals A Graphene-Based Glycan Biosensor for Electrochemical Label-Free Detection of a Tumor-Associated Antibody

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5409 ◽  
Author(s):  
Filip Kveton ◽  
Anna Blsakova ◽  
Lenka Lorencova ◽  
Monika Jerigova ◽  
Dusan Velic ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Secondary Ion Mass Spectrometry ◽  
Covalent Immobilization ◽  
Label Free ◽  
Surface Plasmon Resonance Analysis ◽  
Binding Preference ◽  
Electrochemical Label ◽  
Label Free Detection

The study describes development of a glycan biosensor for detection of a tumor-associated antibody. The glycan biosensor is built on an electrochemically activated/oxidized graphene screen-printed electrode (GSPE). Oxygen functionalities were subsequently applied for covalent immobilization of human serum albumin (HSA) as a natural nanoscaffold for covalent immobilization of Thomsen-nouvelle (Tn) antigen (GalNAc-O-Ser/Thr) to be fully available for affinity interaction with its analyte—a tumor-associated antibody. The step by step building process of glycan biosensor development was comprehensively characterized using a battery of techniques (scanning electron microscopy, atomic force microscopy, contact angle measurements, secondary ion mass spectrometry, surface plasmon resonance, Raman and energy-dispersive X-ray spectroscopy). Results suggest that electrochemical oxidation of graphene SPE preferentially oxidizes only the surface of graphene flakes within the graphene SPE. Optimization studies revealed the following optimal parameters: activation potential of +1.5 V vs. Ag/AgCl/3 M KCl, activation time of 60 s and concentration of HSA of 0.1 g L−1. Finally, the glycan biosensor was built up able to selectively and sensitively detect its analyte down to low aM concentration. The binding preference of the glycan biosensor was in an agreement with independent surface plasmon resonance analysis.

scholarly journals Paper-based fluorogenic RNA aptamer sensors for label-free detection of small molecules

2020 ◽  
Vol 12 (21) ◽  
pp. 2674-2681
Author(s):  
Fatemeh Shafiei ◽  
Kathleen McAuliffe ◽  
Yousef Bagheri ◽  
Zhining Sun ◽  
Qikun Yu ◽  
...  
Keyword(s):  
Small Molecules ◽  
Rapid Detection ◽  
Rna Aptamer ◽  
Label Free ◽  
Target Analytes ◽  
Label Free Detection

A paper-based portable fluorogenic RNA sensor for the selective, sensitive, and rapid detection of target analytes.

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