A convenient fluorescent/electrochemical dual-mode biosensor for accurate detection of Pb2+based on DNAzyme cycle

The presence of heavy metals in the ecological environment is a serious threat to human health. Therefore, it is very important to establish a simple and sensitive method for the detection of heavy metals. Currently, most of the methods are single-channel sensing, and these methods are prone to false-positive signals, which reduces the accuracy. In this work, Pb2+-DNAzyme was immobilized on magnetic beads (MBs) using a linkage of biotin and streptavidin and successfully applied to the construction of a fluorescent/electrochemical dual-mode (DM) biosensor. The supernatant after magnetic separation formed a double strand on the electrode, which was combined with methylene blue (MB) for electrochemical detection (EC). At the same time, FAM-d was added to the precipitate, and after magnetic separation, the supernatant was subjected to fluorescent detection (FL). Under optimal conditions, the signal response of the constructed dual-mode biosensor showed a good linear relationship with the concentration of Pb2+. The DNAzyme-based dual-mode biosensor achieved sensitive and selective detection of Pb2+ with good accuracy and reliability, opening a new way for the development of biosensing strategies for the detection of Pb2+. More importantly, the sensor has high sensitivity and accuracy for the detection of Pb2+ in actual sample analysis.

Automated summary

The presence of heavy metals in the ecological environment presents a serious threat to human health. Therefore, it is crucial to develop a simple and sensitive method for heavy metal detection. In this study, a Pb2+-DNAzyme immobilized on magnetic beads was successfully utilized to construct a fluorescent/electrochemical dual-mode biosensor. The dual-mode biosensor exhibited a good linear relationship between signal response and Pb2+ concentration, achieving accurate and reliable detection of Pb2+ and introducing a new approach for biosensing strategies. Notably, the sensor demonstrated high sensitivity and accuracy in the detection of Pb2+ in real sample analysis.