A convenient paper-based fluorescent aptasensor for high-throughput detection of Pb²⁺ in multiple real samples...

Lead ion (Pb²⁺) is one of the most toxic and widely polluted heavy metal ions. Given the potential health risks and economic losses associated with Pb²⁺, the rapid detection of Pb²⁺ using fluorescent aptasensors is of significant importance in evaluating food safety. A rapid, facile and economic fluorescent aptasensor using convenient paper as the sensing substrate was designed to high-throughput detect Pb²⁺ in complex samples within about 45 min. The Pb²⁺ changed the conformation of FAM-modified Apt from a random coil to a stable G-quadruplex structure. And then Dabcyl-labeled cDNA was added to form double-stranded DNA with the Apt that did not form a G-quadruplex structure, resulting in a weak fluorescence due to the fluorescence resonance energy transfer (FRET). The fluorescent aptasensor showed a positive correlation with Pb²⁺ concentration, and a linear relationship was obtained in the range of 0.01-10 μM with LOD of 6.1 nM. In addition, this method has been successfully used for the determination of Pb²⁺ in water, soil and various foods containing complex substrates. Meanwhile, the high-throughput detection of Pb²⁺ has also reached an acceptable level. Therefore, this convenient strategy has potential application value for on-site rapid detection of Pb²⁺.