Specific Coordination between Zr-MOF and Phosphate-Terminated DNA Coupled with Strand Displacement for the Construction of Reusable and Ultrasensitive Aptasensor

Abstract

Electrochemical aptasensors involved in chemical labeling are often singleuse and sensitivity-limited because the probes are commonly single-point labeled and irreversible. In this work, the specific coordination between Zr 4+ and phosphate group (−PO 4 3− ) was employed to construct a new aptasensor that is highly sensitive and reusable, using Ochratoxin A (OTA) as the test model. The OTA binding aptamer (OBA) was hybridized with the thiolated supporting sequence (TSS) immobilized on the surface of a gold electrode. The UiO-66 with a formula of [Zr 6 O 4 (OH) 4 (BDC) 6 ], one of the class of Zr metal−organic frameworks (MOFs), was then particularly grafted on the terminal of OBA through the specific coordination between Zr 4+ and 5′-PO 4 3− , i.e., the Zr−O−P coordination bond. Similarly, as much as the 5′-PO 4 3− and 3′-methylene blue dual-labeled sequences (DLS) were further assembled on UiO-66 due to the large surface area of MOF and rich active sites of Zr 4+ . Owing to the specific coordination for signal amplification, the developed aptasensor shows greatly enhanced sensitivity. A wide detection range from 0.1 fM to 2.0 μM and an ultralow detection limit of 0.079 fM (S/N = 3) for OTA were obtained. Additionally, the TSS can rehybridize with a new OBA to regenerate the aptasensor but without complicated pretreatments, enabling a aptasensor that is readily reusable for OTA detection. The aptasensor was successfully applied for OTA detection in the red wine samples, demonstrating a promising prospect for food safety monitoring.

Organophosphorus-Functionalized Zirconium-Based Metal–Organic Framework Nanostructures for Improved Mechanical and Flame Retardant Polymer Nanocomposites

“…18 Fourier transform infrared spectroscopy (FTIR) spectra were obtained by an FT-IR spectrophotometer of Bruker Optics using diamond as the background crystal. 31 P magic angle spinning NMR spectra were acquired at 11.7 T using a Bruker Advance III wide bore spectrometer with a 4 mm HXY MAS probe and a spinning rate of 12.5 kHz. Forty scans were acquired with a recycle delay of 2 s and a pulse length of 3 μs.…”

Research Progress of UiO-66-Based Electrochemical Biosensors

“…As a result, Qiu et al constructed a double-labeled sequence electrochemical biosensor utilizing a strong Zr-O-P coordination bond in conjunction with the addition of, UiO-66 to PO 4 3− end group DNA carrying OTA. The sensor exhibits high target recognition capability and does not require sophisticated pre-processing ( Qiu et al, 2020 ).…”

Mycotoxins Detection Based on Electrochemical Approaches

“…Therefore, a variety of GEC methods with excellent detection performance for detecting mycotoxins have been proposed [42][43][44]. Based on the detection signals, GEC biosensors for mycotoxins are described as below:…”

“…Metal-organic frameworks (MOFs) demonstrated superior capability in biosensors development when it used as a carrier of signal molecule due to its advantages, such as well-regulated crystalline structures, high specific surface area, stable channel, as well as substantial metal active sites. A sensitive biosensor with aptamer used to detect OTA, which on the basis of specific coordination between Zr 4 + and À PO 4 3À was developed [44]. Benefiting from combination between Zr 4 + and À PO 4 3À , the UiO-66 assembled on AuE, and MB was also firmly anchored on UiO-66 (Figure 2B).…”

“…The schematic representation of (A) electrochemical minotope peptide-based GEC immunosensor formation for OTA detection; (Reprinted from[53] with permission: © 2019 Elsevier) (B) the construction of the reusable OTA aptasensor. (Reprinted from[44] with permission: © 2020 ACS).…”