Yujie Yu,Min Qing,Yidan Ma,Yan Zhang,Shuting Zheng,Chao Yu,Junlin He
Lead ion (Pb 2+ ) is a major non-degradable environmental pollutant and poses threat to human health. DNAzymes have proved to be a promising tool for the detection of extracellular metal ions . Owing to cellular uptake, enzymatic degradation and reliable signal output, using DNAzymes to quantitative intracellular sensing of Pb 2+ still presents challenges. In this study, we report a core-shell nanoworms-DNAzyme nanoprobe combing hairpin-like DNAzyme (H DNAzyme) with polydopamine-coated Au cores plasmonic “nanoworms” ( [email protected] NWs) for imaging of Pb 2+ in living cells. PDA with good biocompatibility, high near-infrared (NIR) fluorescence quenching efficiency, and provides a larger surface for further functionalization of biomolecules. H DNAzyme can loaded onto [email protected] NWs via coordination interaction and π–π stacking, resulting in significant quenching of their fluorescence by PDA shells and Au cores. In the presence of target Pb 2+ , the H DNAzyme are activated and release Cy5 fluorophore-labeled short strands from [email protected] NWs. Therefore, an increased fluorescence signal is observed and allows imaging of Pb 2+ in living cells. Moreover, the highly selective of H DNAzyme make the proposed method effectively discriminate against other nonspecific molecules. The [email protected] NWs-H DNAzyme nanoprobe shows good biocompatibility and obviously decreased background fluorescence, which can monitor Pb 2+ levels and biodistribution. The developed nanoprobe holds great potential for further extend to bioimaging of other metal ions.
Baoting Dou,Hui Shen,Zhimin Li,Huanyu Cheng,Po Wang
Reactive oxygen species (ROS) play a critical role in regulating various physiological processes. To gain a comprehensive understanding of their distinct functions in different physiological events, it is imperative to detect binary ROS simultaneously. However, the development of the sensing method capable of binary ROS detection remains a significant challenge. In this study, we address this challenge by integrating chemically modified DNAzyme probes with the functionalized metal-organic framework (MOF) to create an efficient electrochemical sensing platform for the binary detection of ROS. ROS targets would activate the DNAzyme cleavage activity by removing the phenylboronate (BO) and phosphorothioate (PS) modifications, leading to the controlled release of doxorubicin (DOX) and methylene blue (MB) enclosed within MOF nanocomposites. This process generates two distinct voltammetric current peaks, with their potentials and intensities reflecting the identity and concentration of the ROS targets. The sensor demonstrates simultaneous detection of multiple ROS (H2O2 and HClO) produced by cancer cells with high sensitivity across a broad linear range of 1 to 200 nM and a low detection limit of sub-nanomolar. The design strategies behind the developed ROS sensing system could also be exploited to create other biosensors with highly sensitive and binary detection to promote clinical research and revolutionize disease diagnostics.
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