An electrochemical aptasensor-based CoxP-decorated porous carbon microspheres and AuNRs labelled methylene blue as signal labels for the sensitive detection of PCB77

Advancements in nanomaterial-based aptasensors for the detection of emerging organic pollutants in environmental and biological samples

The combination of nanomaterials (NMs) and aptamers into aptasensors enables highly specific and sensitive detection of diverse pollutants. The great potential of aptasensors is recognized for the detection of diverse emerging organic pollutants (EOPs) in different environmental and biological matrices. In addition to high sensitivity and selectivity, NM-based aptasensors have many other advantages such as portability, miniaturization, facile use, and affordability. This work showcases the recent advances achieved in the design and fabrication of NM-based aptasensors for monitoring EOPs (e.g., hormones, phenolic contaminants, pesticides, and pharmaceuticals). On the basis of their sensing mechanisms, the covered aptasensing systems are classified as electrochemical, colorimetric, PEC, fluorescence, SERS, and ECL. Special attention has been paid to the fabrication processes, analytical achievements, and sensing mechanisms of NM-based aptasensors. Further, the practical utility of aptasensing approaches has also been assessed based on their basic performance metrics (e.g., detection limits, sensing ranges, and response times).

Highly sensitive and selective detection of PCB 77 using an aptamer-catalytic hairpin assembly in an aquatic environment

Polychlorinated biphenyls (PCBs) are synthetic organic compounds that are extremely difficult to break down in water and can accumulate in human fat and organisms. However, methods that can be used to detect large amounts of PCBs remain unsatisfactory, as they are generally overly sensitive and involve complex operations. An aptamer-based catalytic hairpin assembly (aptamer-CHA) reaction for the selective detection of 3,3′,4,4′-tetrachlorobiphenyl (PCB 77) was developed. It combines the advantages of aptamers and signal amplification reactions. The aptamer selectivity recognizes the target, PCB 77, which triggers the sensitive CHA reaction to produce a fluorescence signal. CHA is a sensitive enzyme-free signal amplification method suitable for on-site detection. Therefore, the identification aptamer is the basis for the quantitative detection of PCB 77, with a detection range of 0.01 μg L⁻¹ to 500 μg L⁻¹ and a detection limit of 0.01 μg L⁻¹. In this study, the aptamer was used to improve the selectivity of the reaction, and the CHA reaction improved the sensitivity of the detection system. Such high-sensitivity PCB detection capabilities with simplified procedures may be useful for real-time field detection and other monitoring tasks. This method can be used as a rapid fluorescence detection strategy for other targets in aquatic environments.

The fluorescence sensing strategy was used to detect PCB77 based on the aptamer-complex and catalytic hairpin assembly.