Space-Confined Electrochemical Aptasensing with Conductive Hydrogels for Enhanced Applicability to Aflatoxin B1 Detection

Abstract

Aflatoxin B1 (AFB1) contamination has received considerable attention for the serious harm it causes and its wide distribution. Hence, its efficient monitoring is of great importance. Herein, a space-confined electrochemical aptasensor for AFB1 detection is developed using a conductive hydrogel. Plasmonic gold nanoparticles (AuNPs) and methylene blue-embedded double-stranded DNA (MB-dsDNA) were integrated into the conductive Au-hydrogel by ultraviolet (UV) polymerization. Specific recognition of AFB1 by the aptamer released MB from MB-dsDNA in the matrix. The free DNA migrated to the outer layer due to electrostatic repulsion during the Au-hydrogel formation. The electrochemical aptasensor based on this Au-hydrogel offered a twofold enlarged oxidation current of MB (I MB) compared with that recorded in the homogeneous solution for AFB1 detection. Upon light illumination, this I MB was further enlarged by the local surface plasmon resonance (LSPR) of the AuNPs. Ultimately, the Au-hydrogel-based electrochemical aptasensor provided a detection limit of 0.0008 ng mL–1 and a linear range of 0.001–1000 ng mL–1 under illumination for AFB1 detection. The Au-hydrogel allowed for space-confined aptasensing, favorable conductivity, and LSPR enhancement for better sensitivity. It significantly enhanced the applicability of the electrochemical aptasensor by avoiding complicated electrode fabrication and signal loss in a bulk homogeneous solution.

Recent Progress of Electrochemical Aptasensors toward AFB1 Detection (2018–2023)

“…Multiple label-free electrochemical aptasensors based on carbon nanotubes [82,87], graphene oxide [80], reduced graphene oxide [55,77,82,85,87], AuNPs [42,76,77,87] or Aubased materials [51,83,86,90], polymers [49,77,80], and MOFs [79] have been reported recently.…”

Programmable DNA Templates for Silver Nanoclusters Synthesis To Develop On-Demand FRET Aptasensor

“…Compared to antibodies, aptamers offer several advantages, including chemical stability, structural feasibility, and ease of chemical synthesis and modification . Consequently, aptamers have a wide range of applications such as medical diagnosis, , environmental analysis, , and food safety monitoring. − Currently, aptamer-modified AgNCs have garnered increasing attention due to the synergistic benefits offered by the combination of AgNCs and aptamers. By appending C-rich sequences to the aptamer, the DNA strands within these aptasensors are engineered to possess a dual functionality.…”