Wenjuan Zhou

Synthesis and Design of Aggregation-Induced Emission Surfactants: Direct Observation of Micelle Transitions and Microemulsion Droplets

The direct visualization of micelle transitions is a long-standing challenge owing to the intractable aggregation-caused quenching of light emission in the micelle solution. Herein, we report the synthesis of a surfactant with a tetraphenylethene (TPE) core and aggregation-induced emission (AIE) characteristics. The transition processes of surfactant micelles and the microemulsion droplets (MEDs) formed by the surfactant with a TPE core were clearly visualized by a high-contrast fluorescence imaging method. The fluorescence intensity of the MEDs decreased as the size of MEDs increased as a result of weakening of the restriction of intramolecular rotation (RIR). The results of this study deepen our understanding of micelle-transition processes and provide solid evidence in favor of the hypothesis that the AIE phenomenon has its origin in the RIR of fluorophores in the aggregate state.

Turn-On Luminescent Probes for the Real-Time Monitoring of Endogenous Hydroxyl Radicals in Living Cells.

The utilization of semiconductor quantum dots (QDs) as optical labels for biosensing and biorecognition has made substantial progress. However, the development of a suitable QD-based luminescent probe that is capable of detecting individual reactive oxygen species (ROS) represents a great challenge, mainly because the fluorescence of QDs is quenched by a wide variety of ROS. To overcome this limitation, a novel QD-based turn-on luminescent probe for the specific detection of (.) OH has been designed, and its application in monitoring the endogenous release of (.) OH species in living cells is demonstrated. Metal citrate complexes on the surfaces of the QDs can act as electron donors, injecting electrons into the LUMO of the QDs, while (.) OH can inject holes into the HOMO of the QDs. Accordingly, electron-hole pairs are produced, which could emit strong luminescence by electron-hole recombination. Importantly, this luminescent probe does not respond to other ROS.

Radical Pair-Driven Luminescence of Quantum Dots for Specific Detection of Peroxynitrite in Living Cells

There is currently great interest in developing chemiluminescence (CL) probes that can selectively detect peroxynitrite (ONOO(-)) in living cells. In comparison with other reactive oxygen species (ROS), ONOO(-) can spontaneously decompose into a series of radicals. Notably, the interaction of quantum dots (QDs) with oxidizing/reducing ROS radicals can generate a strong CL emission by electron-transfer annihilation. Herein, we report a novel CL probe that affords the ability to distinguish ONOO(-) from other ROS in living cells. ONOO(-) can activate luminescence of QDs in the absence of excitation source, effectively avoiding background noise and scattering of light from biological matrixes produced by in situ excitation; however, there is no response to other ROS including (1)O2, H2O2, (•)OH, O2(•-), and ClO(-). The outstanding selectivity of the present CL probe leads us to detect the exogenous release of ONOO(-) from 3-morpholinosydnonimine (SIN-1) in living cells. These results suggest that this present probe-based CL provides a promising platform for highly selective and sensitive detection of ONOO(-) in biological systems.

One-step enrichment and chemiluminescence detection of sodium dodecyl benzene sulfonate in river water using Mg–Al–carbonate layered double hydroxides

In this work, Mg-Al CO3-layered double hydroxides (LDHs) were used as adsorbent materials for sodium dodecyl benzene sulfonate (SDBS) in aqueous solutions, the enriched SDBS can be directly detected by IO4(-)-H2O2 chemiluminescence (CL) system. The commonly existing cations cannot be enriched by Mg-Al CO3-LDHs due to the structurally positively charged layers of LDHs, while other adsorbed anionic interferents had no effect on the IO4(-)-H2O2 CL reaction. The corresponding linear regression equation was established in the range of 0.1-10 μM for SDBS. The detection limit at a signal-to-noise (S/N) ratio of 3 for SDBS was 0.08 μM. The relative standard deviation (RSD) for nine repeated measurements of 0.5 μM SDBS was 2.6%. This proposed method has been successfully applied to the determination of SDBS in river water samples. To the best of our knowledge, we have first time coupled the high enrichment capacity of LDHs towards anions with CL detection for analytes.

Natural montmorillonite nanosheet colloid-catalyzed hydrogen peroxide ultra-weak chemiluminescence

A natural framework in montmorillonite nanosheet colloids is found to enhance hydrogen peroxide ultra-weak chemiluminescence. This work indicates a transformation of nanoparticle-catalyzed chemiluminescence from synthetic to natural.