Search

DNA-based molecular circuits able to perform complex information processing in biological systems are highly desirable. However, conventional DNA circuits are constitutively always in an ON state and immediately operate when they meet the biomolecular inputs, precluding precise molecular computation at a desired time and in a desired site. In this work, we report a conceptual methodology for the construction of photonic nanocircuits that enable DNA molecular computation in vitro and in vivo with high spatial precision. Upon remote activation by spatially restricted NIR-light input, two types of cancer biomarker inputs can sequentially trigger conformational changes of the DNA circuit through a structure-switching aptamer and toehold-mediated strand exchange, leading to release of a signaling output. Of note, the NIR-light-gated nanocircuit allows for intended control over the specific timing and location of DNA computation, providing spatial and temporal capabilities for multiplexed imaging. Furthermore, an OR-AND-gated nanocircuit of higher complexity was designed to illustrate the versatility of our approach. The present work illustrates the potential of the use of upconversion nanotechnology as a regulatory tool for spatial and temporal control of DNA computation in cells and animals.

It is crucial for cell physiology to keep the homeostasis of pH, and it is highly demanded yet challenging to develop luminescence resonance energy transfer (LRET)-based near-infrared (NIR) ratiometric luminescent sensor for the detection of pH fluctuation with NIR excitation. As promising energy donors for LRET, upconversion nanoparticles (UCNPs) have been widely used to fabricate nanosensors, but the relatively low LRET efficiency limits their application in bioassay. To improve the LRET efficiency, core/shell/shell structured β-NaGdF4@NaYF4:Yb,Tm@NaYF4 UCNPs were prepared and decorated with hemicyanine dyes as an LRET-based NIR ratiometric luminescent pH fluctuation-nanosensor for the first time. The as-developed nanosensor not only exhibits good antidisturbance ability, but it also can reversibly sense pH and linearly sense pH in a range of 6.0–9.0 and 6.8–9.0 from absorption and upconversion emission spectra, respectively. In addition, the nanosensor displays low dark toxicity under physiological tem...

Previous reports of fluorescent sensors for alcohols based on charge-transfer character of their excited state are based on mono-, di-, and tetra-phosphonate cavitands, which are capable of selecting analytes through shape/size selection and various specific H-bonding, CH-π, and cation-dipole interactions. To contrast, color changes based on absorption properties of the ground state are more suitable for direct observation with the naked eye. Three sensitive and selective colorimetric sensors for C1-C4 alcohols have been developed on the basis of alcohol-mediated ground-state intramolecular proton transfer. Reverse proton transfer induced by water achieves a fully reversible reaction. In addition, the solvent color indicates alcohol concentration.