Ratiometric Sensing for Ultratrace Tetracycline Using Electrochemically Active Metal–Organic Frameworks as Response Signals

Abstract

single-stranded DNA (ssDNA), and complex system (Apt@NH 2 -UiO-66) of aptamer (Apt) and NH 2 -UiO-66 were sequentially immobilized on the electrode. With the addition of TET, Apt was hybridized with TET and Apt@NH 2 -UiO-66 was detached from the electrode, resulting in an increase in the current at −1.06 V and a decrease in the current at 0.724 V. Through this strategy, the sensor achieved a wide linear range (0.1−10000 nM) and a low limit of detection (0.009792 nM) for TET. Moreover, the ratiometric sensor exhibited better sensitivity, reproducibility, and stability than a singlesignal sensor. Furthermore, the constructed sensor was successfully applied to detect TET in milk samples, suggesting excellent application prospects.

Tetrahedral DNA Nanostructure-Engineered Paper-Based Electrochemical Aptasensor for Fumonisin B1 Detection Coupled with Au@Pt Nanocrystals as an Amplification Label

“…The EIS results were fitted with the Randles electronic equivalent circuit (inset in Figure B), which consisted of the resistance of solution ( R s ), the electron transfer resistance ( R et ), the double-layer capacitance ( C dl ), and the Warburg impedance ( Z w ). As for R et , it is related to the diameter of the semicircle in the high-frequency region. , Similarly, R et decreased when AuNPs@MXenes were coated on the electrode surface because of the good conductivity of AuNPs@MXenes (curve b). After the successive immobilization of cDNA–TDNs, MCH, and Apt-Au@Pt NCs, R et gradually increased (curves c, d, and e) as a result of the steric hindrance of the biomolecule.…”

“…As for R et , it is related to the diameter of the semicircle in the high-frequency region. 33,34 Similarly, R et decreased when AuNPs@MXenes were coated on the electrode surface because of the good conductivity of AuNPs@MXenes (curve b). After the successive immobiliza- tion of cDNA−TDNs, MCH, and Apt-Au@Pt NCs, R et gradually increased (curves c, d, and e) as a result of the steric hindrance of the biomolecule.…”

Signal Modulation of Organic Photoelectrochemical Transistor by a Z-Scheme Photocathodic Gate: An Innovative Dual Amplification Strategy for Sensitive Aptasensing Application

“…The calibration equation was I DS = 5.91 lg C + 79.28 ( R 2 = 0.999) with a calculated LOD of 4.0 × 10 –13 M. In addition, thanks to the dual signal amplification of the innovative OPECT device, a wider linear range and lower LOD toward TC analysis were observed compared with other electrochemical and PEC methods reported in the recent literature (Table S1). ,− …”