Deterministic positioning and alignment of a single-molecule exciton in plasmonic nanodimer for strong coupling.

Experimental realization of strong coupling between a single exciton and plasmons remains challenging as it requires deterministic positioning of the single exciton and alignment of its dipole moment with the plasmonic fields. This study aims to combine the host-guest chemistry approach with the cucurbit[7]uril-mediated active self-assembly to precisely integrate a single methylene blue molecule in an Au nanodimer at the deterministic position (gap center of the nanodimer) with the maximum electric field (EFmax) and perfectly align its transition dipole moment with the EFmax, yielding a large spectral Rabi splitting of 116 meV for a single-molecule exciton-matching the analytical model and numerical simulations. Statistical analysis of vibrational spectroscopy and dark-field scattering spectra confirm the realization of the single exciton strong coupling at room temperature. Our work may suggest an approach for achieving the strong coupling between a deterministic single exciton and plasmons, contributing to the development of room-temperature single-qubit quantum devices.

A turn-on fluorescent probe for sensing N2H4 in living cells, zebrafishes and plant root with a large turn-on fluorescence signal.

Hydrazine (N2H4) plays an important role in industrial production, but it is highly toxic, leaking or exposing it will pollute the environment and cause serious harm to human beings. Therefore, it is necessary to use a simple and effective method to detect N2H4 in environmental systems and organisms. Herein, a novel water-soluble fluorescent probe based on coumarin fluorophore, 2-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)isoindoline-1,3-dione (C-Z1), is reported. The fluorescence intensity of the probe at 530 nm was enhanced gradually with the addition of N2H4, and the maximum enhancement was about 28 times. The probe has good selectivity and sensitivity, the detection limit of hydrazine hydrate is 1.48 × 10-7 M, and the response mechanism of the probe is proved by theoretical calculation and experiment. C-Z1 has been shown to detect N2H4 in a variety of environmental samples, including water, soil, air, cells, zebrafish and plants. In addition, C-Z1 can be made into test strips for easy portability and used for rapid quantitative detection of N2H4 in the field by its distinct change in fluorescence color. Thus, C-Z1 has great potential for the analysis and detection of environmental contaminants.

A highly sensitive and low toxicity cellulose-based fluorescent polymer for H2S detection in cells, zebrafish and food samples.

A cellulose based polymer probe (HC-HS) was prepared for the detection of H2S. HC-HS can be applied to fluorescence imaging of H2S in living cells and zebrafish, and HC-HS was made into test strips to detect H2S produced in the process of food corruption.

Development of a two-photon fluorescent probe for imaging hydrogen sulfide (H2S) in living cells and zebrafish.

We present a new two-photon fluorescent probe (T-HS) for the detection of H2S. With the addition of hydrogen sulfide, the absorption and fluorescence spectra of the probe show regular changes. The probe exhibited favorable properties, such as large turn-on fluorescence signal, good selectivity and low cytotoxicity. Moreover, the probe T-HS was successfully used for the fluorescence imaging of H2S in live cells and zebrafish.

Construction of a water-soluble fluorescent probe for copper (II) ion detection in live cells and food products.

The quality of wine can be affected by excess Cu2+ due to the occurrence of oxidation reactions or precipitation. Therefore, it is essential to use simple and effective testing methods to ensure the Cu2+ content in wine. In this work, we designed and synthesized a rhodamine polymer fluorescent probe (PEG-R). The water solubility of PEG-R was improved by the introduction of polyethylene glycol, which improved the performance and broadened its application in the food field. The PEG-R was characterized by high sensitivity, selectivity and fast response to Cu2+ and was able to complete the response process within 30 s, with approximately 29-fold fluorescence enhancement of the probe after exposure to Cu2+, the limit of detection (LOD) was 1.295 × 10-6 M. The probe can be used for the determination of Cu2+ in living cells, zebrafish, white wine and food products, and it was made into practical gels and test strips.