Rapid, Multiplexed, and Enzyme-Free Nucleic Acid Detection Using Programmable Aptamer-Based RNA Switches.

Rapid, simple, and low-cost diagnostic technologies are crucial tools for combatting infectious disease. We describe a class of aptamer-based RNA switches or aptaswitches that recognize target nucleic acid molecules and initiate folding of a reporter aptamer. Aptaswitches can detect virtually any sequence and provide an intense fluorescent readout without intervening enzymes, generating signals in as little as 5 minutes and enabling detection by eye with minimal equipment.

Electron count and ligand composition influence the optical and chiroptical signatures of far-red and NIR-emissive DNA-stabilized silver nanoclusters.

Near-infrared (NIR) emissive DNA-stabilized silver nanoclusters (Ag-DNAs) are promising fluorophores in the biological tissue transparency windows. Hundreds of NIR-emissive Ag-DNAs have recently been discovered, but their structure-property relationships remain poorly understood. Here, we investigate 19 different far-red and NIR emissive Ag-DNA species stabilized by 10-base DNA templates, including well-studied emitters whose compositions and chiroptical properties have never been reported before.

Chloride Ligands on DNA-Stabilized Silver Nanoclusters.

DNA-stabilized silver nanoclusters (Ag-DNAs) are known to have one or two DNA oligomer ligands per nanocluster. Here, we present the first evidence that Ag-DNA species can possess additional chloride ligands that lead to increased stability in biologically relevant concentrations of chloride. Mass spectrometry of five chromatographically isolated near-infrared (NIR)-emissive Ag-DNA species with previously reported X-ray crystal structures determines their molecular formulas to be (DNA)[AgCl].