No abstract

Split halves of a hemin-binding DNAzyme have been assembled with an anti-adenosine aptamer to build a homogeneous allosteric sensor for adenosine with high selectivity and sensitivity.

A sensitive and fully DNA-structured ion sensor was built by integrating polyT sequences for highly selective Hg2+ recognitions and two flanking G-quadruplex halves for allosteric signal transductions. The construction of this sensor was very easy that allowed a cost-effective detection of Hg2+ with a limit of detection of 4.5 nM, which was lower than the 10 nM toxic level for drinkable water as regulated by the US's EPA. The strategy employed for the construction of this sensor may be further extended to other sensors through a rational structural fusion between re-engineered aptameric and enzymic DNA sequences.

No abstract

Visual detection of mercury ions and glutathione is of great significance to public health and environmental issues. Herein, we developed a fluorescent sensor (l-Cys/CuNCs@ESM) based on the eggshell membrane (ESM) and red-emitting copper nanoclusters (CuNCs) by the in situ strategy via l-cysteine (l-Cys) as the reducing and protective agent for mercury ions and glutathione sensing visually. The as-prepared fluorescent product had good stability, portability, large Stokes shift (250 nm), and long fluorescence lifetime (7.3 μs). Notably, the l-Cys/CuNCs@ESM exhibited a specific fluorescence quenching response toward Hg2+. Moreover, the interaction between glutathione (GSH) and Hg2+ could subsequently recover the fluorescence effectively. Inspired by this “on-off-on” switch, the l-Cys/CuNCs@ESM was applied as the dual-sensing system for visual detection of mercury ions and glutathione integrating with the portable smartphone. The limit of detection (LOD) of Hg2+ is 1.1 μM for visualization and 0.52 μM for the fluorescence spectrometer. The corresponding LODs of GSH are 2.8 and 0.59 μM, respectively. This platform presents significant sensitivity, specificity, and stability, offering a promising potential for real-time/on-site sensing.