Construction of a novel fluorescent DNA aptasensor for the fast-response and sensitive detection of copper ions in industrial sewage

Abstract

Heavy metal pollution poses a great threat to the ecological environment and human health. In particular, copper ions (Cu²⁺) play a vital role in regulating fundamental life behavior, and the homeostasis of Cu²⁺ is closely related to many physiological processes. The excessive accumulation of Cu²⁺ in the human body through food and drinking water will cause severe diseases. However, current conventional Cu²⁺ detection methods for evaluating the content of Cu²⁺ are unable to meet the complete requirements of practical Cu²⁺ analysis in the practical aquatic environment. In this work, we successfully constructed a novel fluorescent DNA aptasensor, which originated from the binding reaction between the improved DNA fluorescent light-up aptamer termed S2T3_AT-GC and a small fluorescent molecule termed DFHBI-1T (S2T3_AT-GC/DFHBI-1T) to realize fast and anti-interference response for Cu²⁺via the competitive interaction between Cu²⁺ and S2T3_AT-GC (Cu²⁺/S2T3_AT-GC) destroying the contained G-quadruplex structure of S2T3_AT-GC. Moreover, it enables the sensitive detection of Cu²⁺ with a detection limit of 0.3 μM and a wide detection linear range from 0.3 to 300 μM. Moreover, with the verification of high stability in real industrial sewage samples, this aptasensor exhibits excellent detection performance for Cu²⁺ analysis in real water samples. Therefore, the proposed aptasensor exhibits great potential in exploring Cu²⁺-related environmental and ecological research.