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350 results on '"Yuan, Qunhui"'

3. Probing the structural evolution on the surface of cardiolipin vesicles with an amphiphilic second harmonic generation and fluorescence probe.

Author

Chen, Shujiao, Liu, Zhongcheng, Li, Bifei, Hou, Yi, Peng, Yingying, Li, Jianhui, Yuan, Qunhui, and Gan, Wei

Subjects
SECOND harmonic generation, CARDIOLIPIN, FLUORESCENCE, DRUG carriers
Abstract

Investigating the influence of the ambient chemical environment on molecular behaviors in liposomes is crucial for understanding and manipulating cellular vitality as well as the capabilities of lipid drug carriers in various environments. Here, we designed and synthesized a second harmonic generation (SHG) and fluorescence probe molecule called Pyr-Py+-N+ (PPN), which possesses membrane-targeting capability. We employed PPN to investigate the response of lipid vesicles composed of cardiolipin to the presence of exogenous salt. The kinetic behaviors, including the adsorption and embedding of PPN on the surface of small unilamellar vesicles (SUVs) composed of cardiolipin, were analyzed. The response of the SUVs to the addition of NaCl was also monitored. A rapid decrease in vesicle size can be evidenced through the rapid drop in SHG emission originating from PPN located on the vesicle surface. [ABSTRACT FROM AUTHOR]

Published
2024
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7. MOF-derived ZnO/g-C3N4 nanophotocatalyst for efficient degradation of organic pollutant

Author

Sadaf Mutahir, Muhammad Asim Khan, Yuan Qunhui, Sheeraz Mehboob, Mohamed Bououdina, Safaa Mostafa Elkholi, Abbas Khan, Rasha A. Abumousa, and Muhammad Humayun

Subjects
g-C3N4, MOF derived ZnO, Photocatalysis, Charge separation, Rhodamine B dye, Chemistry, QD1-999
Abstract

With the use of facile single-step calcination of Zinc glutamate MOF and melamine, highly efficient ZnO/g-C3N4 nanocomposite was prepared and utilized in photocatalytic degradation of Rhodamine B (RhB), an organic pollutant. The composite's morphology, crystallinity, optical properties, and composition were determined using several analytical techniques, which include scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), diffuse reflectance spectroscopy. The degradation of RhB over the optimized 1.0%ZnO/g-C3N4 composite is ∼1.77 fold higher compared to the pure g-C3N4 under identical conditions. The synergistic interfacial interaction between g-C3N4 and MOF derived ZnO remarkably improved the electron-hole pairs separation, which led to the exceptionally high photocatalytic activity of the composite photocatalysts. Based on the radical scavenger tests and ESR analysis, it is confirmed that •O2− as the dominant active specie facilitated the degradation of RhB over the as-prepared ZnO/g-C3N4 composites. This work will open up new insights for further research on g-C3N4 based composite materials.

Published
2024
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41. Stability of fluorescence emission from gold nanoclusters and photocatalytic redox on surface†.

Author

Zeb, Johar, Guo, Huijun, Yuan, Qunhui, and Gan, Wei

Subjects
GOLD clusters, BAND gaps, FLUORESCENCE, OXIDATION-reduction reaction, FEMTOSECOND lasers, INFRARED lasers
Abstract

The fluorescent emission and the photocatalytic activity of gold nanoclusters (AuNCs) are important properties of AuNCs. Here, we synthesized water-soluble, captopril (Capt) and glutathione (GSH) covered Au25(Capt)18 and Au15(GSH)13 nanoclusters and investigated their fluorescence stabilities which are correlated with the photo-redox of their surface. It was observed that Au25(Capt)18 exhibited a decay in its two-photon fluorescence emission induced by surface oxidation upon irradiation of femtosecond near-infrared laser (810 nm, 300 mW) in the presence of oxygen (O2). On the other hand, the two-photon fluorescence from Au15(GSH)13 was stable upon the same excitation. The different stabilities of the fluorescence of the two AuNCs were attributed to their different band gaps. This interpretation was confirmed by one-photon excitation with photon energy beyond the band gaps of the two AuNCs. Using experiments with the addition of several agents, the photocat alytic redox activities of gold atoms on the surface of Au25(Capt)18 were understood and tuned. [ABSTRACT FROM AUTHOR]

Published
2024
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48. Monitoring the response of a model protocell to dye and surfactant molecules through second harmonic generation and fluorescence imaging.

Author

Li, Bifei, Li, Jianhui, Chen, Shujiao, Yuan, Qunhui, Fang, Chao, and Gan, Wei

Abstract

Probing the interaction between molecules and protocells is crucial for understanding the passive transport of functional molecules in and out of artificial and real cells. Second-harmonic generation (SHG) has been proven to be a powerful method for analyzing the adsorption and cross-membrane transport of molecules on lipid bilayers. In this study, we used SHG and two-photon fluorescence (TPF) imaging to study the interaction of charged dye molecules (D289) with a lipid vesicle. Unexpectedly, it was observed that the transport of D289 at a relatively high concentration is not as efficient as that at a lower dye concentration. Periodic shrinking of the model protocell and discharging of D289 out from the vesicle were revealed by combined analyses of SHG and TPF images. The response of the vesicle to a surfactant was also analyzed with D289 as a probe. This work demonstrates that the combined SHG and TPF imaging method is a unique approach that can provide detailed information on the interaction of molecules and lipids (both morphology and molecular kinetics). Determining these subtle interfacial kinetics in molecules is important for understanding the mechanism of many biophysical processes occurring on lipids. [ABSTRACT FROM AUTHOR]

Published
2024
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