scholarly journals Label-Free and Sensitive Determination of Cadmium Ions Using a Ti-Modified Co3O4-Based Electrochemical Aptasensor

Biosensors ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 195
Author(s):  
Yang Liu ◽  
Dongwei Zhang ◽  
Jina Ding ◽  
Kashif Hayat ◽  
Xijia Yang ◽  
...  
Keyword(s):  
Environmental Protection Agency ◽  
Concentration Limit ◽  
Co3o4 Nanoparticles ◽  
Label Free ◽  
Current Signal ◽  
Electrochemical Aptasensor ◽  
Screen Printed Carbon Electrode ◽  
Sensitive Determination

The current work demonstrates an electrochemical aptasensor for sensitive determination of Cd2+ based on the Ti-modified Co3O4 nanoparticles. In this unlabeled system, Ti-modified Co3O4 nanoparticles act as current signal amplifiers modified on the screen-printed carbon electrode (SPCE) surface, while the derivative aptamer of Cd2+ works as a target recognizer. In addition, the sensing is based on the increase in electrochemical probe thionine current signal due to the binding of aptamer to Cd2+ via specific recognition. In the current study, key parameters, including aptamer concentration, pH, and incubation time were optimized, respectively, to ensure sensing performance. Cyclic voltammetry was used not only to characterize each preparation and optimization step, but also to profile the bindings of aptamer to Cd2+. Under optimal conditions, Cd2+ can be determined in a linear range of 0.20 to 15 ng/mL, with a detection limit of 0.49 ng/mL, significantly below the maximum concentration limit set by the U.S. Environmental Protection Agency. Based on comparative analysis and the results of recovery test with real samples, this simple, label-free but highly selective method has considerable potential and thus can be used as an in-situ environmental monitoring platform for Cd2+ testing.

Encapsulation of hemin in Fe-based metal-organic frameworks and its application for the direct determination of aflatoxin M1

2021 ◽  
pp. 1-10
Author(s):  
F. Jahangiri-Dehaghani ◽  
H.R. Zare ◽  
Z. Shekari
Keyword(s):  
Electrochemical Impedance ◽  
Metal Organic Frameworks ◽  
Direct Determination ◽  
Differential Pulse ◽  
Aflatoxin M1 ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Selective Determination ◽  
Metal Organic

A label-free electrochemical aptasensor was constructed for the sensitive and selective determination of AFM1. For preparation of the aptasensor, the AFM1 aptamer was immobilised on the surface of a glassy carbon electrode modified with hemin encapsulated in Fe-based metal-organic frameworks (hemin@Fe-MIL-101). The morphology and the structure of Fe-MIL-101 and hemin@Fe-MIL-101 were evaluated by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction and Brunauer-Emmett-Teller-N2 sorption methods. Electrochemical impedance spectroscopy and cyclic voltammetry were performed to monitor the fabrication process of the electrochemical aptasensor. The electrochemical reduction current of hemin encapsulated in Fe-MIL-101 serves as a signal for the quantitative determination of AFM1. Differential pulse voltammetry was done to determine the AFM1 concentration in the linear range of 1.0×10-1-100.0 ng/ml. The detection limit of AFM1 was estimated to be 4.6×10-2 ng/ml. Finally, the fabricated aptasensor was applied to determine AFM1 in raw and boiled milk samples.

A novel label-free and enzyme-free electrochemical aptasensor based on DNA in situ metallization

2015 ◽  
Vol 74 ◽  
pp. 483-490 ◽  
Author(s):  
Yong Qian ◽  
Fenglei Gao ◽  
Lili Du ◽  
Yu Zhang ◽  
Daoquan Tang ◽  
...  
Keyword(s):  
Label Free ◽  
Electrochemical Aptasensor
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