| Aptamer, refers to the DNA/RNA from synthetic library screening, a kind of single-stranded oligonucleotide can get high affinity and high specificity with target molecules. Aptamer, the new revolutionary changes have taken place in the antibody or antigen, make up for the deficiency of the existing antibody, also for the traditional immune sensor development has opened up a new path. Which has successfully created a large number of new method based on the analysis of nucleic acid aptamer, including colorimetric method, electrophoresis, piezoelectric, flow injection, surface plasmon resonance, fluorescence, electrochemistry method, etc.Electrochemical technology with high sensitivity, less chemical reagents, the operation is simple, and can detect in the body, the nucleic acid aptamer recognition elements combined with various electrochemical transducer to build a new generation of electrochemical sensors, nucleic acid aptamer has become an important frontier research of analytical chemistry and life science. Although the researchers have explored a variety of new method to construct DNA aptamer electrochemical sensors, and obtained the satisfactory performance analysis, but the aptamer electrochemical sensor research is still in its primary stage, many important questions is still worth to study further. Due to DNA (especially RNA) of nucleic acid enzyme hydrolysis is very sensitive, It requires that the application under the environment of high purity. At present, the performance of aptamer electrochemical sensor and the various parameters (such as the constant of aptamer interact with target material, the recognition mechanism of aptamer, the modification and optimization of sensor electroactive probe, etc) of the research and evaluation are not sufficient, also need to expand the application in the actual system.1Novel electrochemical aptamer biosensor based on gold nanoparticles signal amplification for the detection of carcinoembryonic antigenThe electrochemical biosensor was constructed by sandwiching the carcinoembryonic antigen (CEA) between a Au electrode modified with thiol-terminated CEA aptamer-2and the AuNPs with thiol-terminated CEA aptamer-1and6-ferrocenyl hexanethiol (Fc). Electrochemical impedance and cyclic voltammetry was used to carry out the characterization of the modified electrodes. Amperometric detection of Fc by differential pulse voltammetry (DPV) on the electrochemical biosensor was used to quantify the concentration of CEA. On the one hand, large specific surface of gold nanoparticles led to significant signal amplification, On the other hand, two different aptamers for CEA identification at the same time, The higher identification accuracy than a single aptamer, resulting in a low background signal and a desirable selectivity. The electrochemical biosensor exhibited the excellent selectivity responses and good stability toward the target analyte. The biosensor provided a linear range from1to200ng/mL for CEA with a detection limit of0.5ng/mL. And the performance was successfully evaluated with human serum spiked with CEA.2Ultrasensitive electrochemical aptamer biosensor for adenosine triphosphate detection based on exonuclease Ⅲ electrochemical signal amplificationA hairpin-aptamer probe is ingeniously designed. The presence of the target ATP leads to conformational changes of the aptamer probes and creates catalytic cleavage sites for ExoⅢ to recycle ATP to achieve significant signal amplification. Electrochemical and fluorescence technology was used to carry out the characterization of the modified electrodes. The amplification strategy greatly improved the sensitivity for detection of ATP, it provided a linear range from0.1to20nM for ATP with a detection limit of33pM. Our approach exhibits excellent selectivity for ATP against other analogous molecules. The advantageous merits of the proposed method thus offer great potential for the development of simple and robust sensing strategies for the detection of other small molecules. |
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