Electrochemiluminescence and electrochemical dual-mode biosensing platform for highly sensitive monitoring of PFOA with RuPCN-224 metal organic framework emitters and aptamer-based sandwich assay.

BACKGROUND: Perfluorooctanoic acid (PFOA) can cause thyroid disorders, immune system dysfunction, and liver diseases and even cancer. Developing sensitive detection methods for trace PFOA in environmental matrices is of vital importance for safeguarding human health. As an emerging technique, electrochemiluminescence (ECL) has been extensively studied for detecting environmental pollutants because of near-zero background and superior detection sensitivity. However, current ECL methods are mainly relied on single-mode readout which can induce false positive and negative results. It is extremely imperative to design highly accurate dual-mode analytical systems based on ECL technique for reliable and efficient monitoring of PFOA.

RESULTS: We developed a dual-mode ECL and electrochemical (EC) biosensing platform for sensitive monitoring of PFOA pollutants. RuPCN-224, as a metal organic framework structure, was synthesized with hydrothermal method and used as both ECL emitter and electrochemical active species. HDNA was introduced via glutaraldehyde coupling and aptamer-based sandwich assay was subsequently constructed by the DNA hybridization. Due to the high emitting efficiency of RuPCN-224, robust ECL intensity was observed in ECL mode. When exposed to PFOA pollutants, the ECL emission reduced due to detachment of RuPCN-224 induced by the aptamer-PFOA binding. In electrochemical mode, the electrochemical signal probes, RuPCN-224, broke away from the electrode in the presence of PFOA, resulting in the reduction of DPV current. Under optimized conditions, a remarkably sensitive dual-mode system was constructed for the monitoring of PFOA pollutants with detection limit of 0.97 ng/mL in ECL mode and 0.14 ng/mL in electrochemical mode.

SIGNIFICANCE: The biosensor exhibited superior selectivity against interferences, such as perfluorooctanesulfonic acid (PFOS). In real sample analysis, the biosensor showed good practicality with acceptable recovery and RSD in ECL and electrochemical mode. Combining the RuPCN-224 emitters and aptamer-based assay, the dual-mode biosensor could achieve highly efficient performances for PFOA detection which provided novel design for pollutants monitoring and showed great potential for safeguarding atmospheric environment.