Engineering of An Aptamer-Functionalized Fluorescent DNA Sensor for Cu(II) Responding in Living Tumor Cells

Copper ions play vital roles in regulating life processesand beingclosely involved in several diseases such as cancer. Although detectionmethods based on fluorescent sensors or other strategies have beendeveloped, it still remains a challenge to simultaneously realizethe convenience, specificity, and accuracy in intracellular copperion analysis. Herein, we propose an aptamer-functionalized DNA fluorescentsensor (AFDS) for accurate and specific detection of Cu-(II) both invitro and in cells by engineering the linkage of two DNA aptamers,namely, Lettuce aptamer and AS1411 aptamer, to achieve the mannerof recognition response. Taking advantage of the functions of eachaptamer, the tumor cell recognition capability and the high-contrastdetection performance are simultaneously equipped in the AFDS. Furthermore,the AFDS shows high specificity and selectivity in Cu-(II) responseto avoid interference from common metal ions, chelators, and reactantsby being associated with the irreversible interaction between nucleobasesand Cu-(II), which can destroy the topological structures and switchoff the fluorescence of the AFDS. It also enables a sensitive in vitrodetection of Cu-(II) with a detection limit as lower as 0.1 mu Mand a wide detection linear range from 0.1 to 300 mu M. The feasibilityand superiority of the AFDS provide an opportunity to reveal bothconcentration-dependent and time-dependent intracellular Cu-(II) responsesin living cells. Therefore, the AFDS has achieved the novel detectionperformance of Cu-(II) to exhibit great potential in exploring copper-relatedbiological and pathological research.

Automated summary

In this study, an aptamer-functionalized DNA fluorescent sensor (AFDS) was proposed for accurate and specific detection of Cu-(II) both in vitro and in cells. The AFDS showed high specificity, selectivity, and sensitivity in Cu-(II) response, enabling the detection of Cu-(II) in a wide linear range. The AFDS has great potential in exploring copper-related biological and pathological research.