Bioorthogonal Light-Up Fluorescent Probe Enables Wash-Free Real-Time Dynamic Monitoring of Cellular Glucose Uptake.

As a significant energy source for living systems, the aberrant cellular glucose uptake is seriously implicated in numerous metabolic diseases. Unfortunately, current shortage of robust tools leaves the limitation to understand its precise biology. Herein we presented a bioorthogonal light-up fluorescent probe consist of two reagents, Glu-HT-Me+AzGlu2, for rapidly responsive (within 25 min), highly specific and sensitive (20-folds enhancement) detection of live-cell glucose uptake based on arylphosphine-induced a-PET effect and Staudinger ligation. Especially, taking the advantage of wash-free characteristic, the probe displayed the real-time dynamic monitoring of cellular glucose uptake. Furthermore, it was successfully capable of not only differentiating cancer cells from normal cells, but also allowing evaluation of anticancer/glycolysis/transport mediated glucose flux. Importantly, it was employed to monitor the fluctuations of glucose uptake in a doxycycline-inducible K-rasG12 V expression oncogenic cell system, implying its potential as a valuable tool to explore glucose uptake biology.

A ratiometric ESIPT probe based on 2-aza-Cope rearrangement for rapid and selective detection of formaldehyde in living cells.

Formaldehyde (FA) is a crucial reactive signaling molecule participating in epigenetic and metabolic pathways. However, abnormally elevated levels of FA are implicated in various diseases spanning from tumors to neurodegenerative disorders. Despite being highly selective for FA, current 2-aza-Cope-based fluorescent probes leave room for improvement because their relatively slow reaction kinetics (1-9 hours response time) hinder their capability to track transient biological FA. Herein, we present a ratiometric fluorescent probe, FormAFP, based on excited state intramolecular photon transfer (ESIPT) for rapid (within 10 min), selective (above 70-fold over other RCS) and sensitive (240-times fluorescence enhancement with 66 nM detection limit) detection of FA via 2-aza-Cope rearrangement. The probe also displayed a fast response (<20 min) to both exogenous and endogenous FA in living cells. Besides, FormAFP was capable of monitoring FA released by folate degradation in living MCF7 cells. More importantly, FormAFP successfully detected fluctuations of endogenous FA levels in oxidative stress stimulation, demonstrating its potential as an ideal tool to explore FA biology.

Active cellulose acetate/purple sweet potato anthocyanins@cyclodextrin metal-organic framework/eugenol colorimetric film for pork preservation.

As a natural pH-sensing colorant, purple sweet potato anthocyanins (PSPAs) have demonstrated great potential in colorimetric film for freshness monitoring. However, the photothermal instability of PSPAs is still a challengeable issue. Herein, γ-cyclodextrin metal-organic framework (CD-MOF) loaded with PSPAs (PSPAs@CD-MOF, i.e., PM) and eugenol (EUG) were incorporated in cellulose acetate (CA) matrix for developing a smart active colorimetric film of CA/PM/EUG, where PM and EUG were hydrogen-bonded with CA. Attentions were focused on the photothermal colorimetric stability, colorimetric response, and antibacterial activity of the films. The presence of PM and EUG endowed the film outstanding UV-blocking performance and enhanced the barrier against water vapor and oxygen. Target film of CA/PM15/EUG10 had good photothermal colorimetric stability due to the protection of CD-MOF on PSPAs and the color changes with pH-stimuli were sensitive and reversible. In addition to antioxidant activity, CA/PM15/EUG10 had antibacterial activity against Escherichia coli and Staphylococcus aureus. The application trial results indicated that the CA/PM15/EUG10 was valid to indicate pork freshness and extended the shelf-life by 100 % at 25 °C, which has demonstrated a good perspective on smart active packaging for freshness monitoring and shelf-life extension.