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A novel series of resveratrol modified by γ-aminobutyric acid esters were designed and synthesized. Then, the products were characterized by 1H-NMR, 13C-NMR, and MS, and the melting point was determined. Molecular water solubility, polar surface area, and octanol-water partition were calculated, which correlated well with molecular transport through membranes and, therefore, enabled prediction of transport properties of drugs. [ABSTRACT FROM AUTHOR]

The resveratrol functionalized carboxymethyl-β-cyclodextrin conjugate was synthesized by two simple steps. The conjugate was successfully demonstrated by 1H NMR, 13C NMR, UV, and FTIR. The photostability of the conjugate was studied by ultraviolet absorption spectrum. After 360 min of UV light irradiation, the conjugate showed a total loss in absorbance of only 12.54%, while the resveratrol and its CM-β-CD inclusion complex showed a total loss in absorbance of 32.15% and 24.05%, respectively. The results indicate that the conjugate was more stable than resveratrol and its CM-β-CD inclusion complex. [ABSTRACT FROM AUTHOR]

Fluorescent dyes have enabled much progress in the broad range of biomedical fields. However, many commercially available dyes suffer from small Stokes shifts, resulting in poor signal-to-noise ratio and self-quenching on current microscope configurations. In this work, we have developed a general method to significantly increase the Stokes shifts of common fluorophores. By simply appending a 1,4-diethyl-decahydro-quinoxaline (DQ) moiety onto the conjugated structure, we introduced a vibronic backbone that could facilely expand the Stokes shifts, emission wavelength, and photostability of 11 different fluorophores by more than 3-fold. This generalizable method could significantly improve the imaging efficiency of commercial fluorophores. As a demonstration, we showed that the DQ derivative of hemicyanine generated 5-fold signal in mouse models over indocyanine green. Furthermore, the DQ-modified fluorophores could pair with their parent molecules to conduct one-excitation, multiple emission imaging, allowing us to study the cell behavior more robustly. This approach shows promise in generating dyes suitable for super-resolution microscopy and second window near-infrared imaging. [ABSTRACT FROM AUTHOR]

Cell membrane-targeted bioimaging is a prerequisite for studying the roles of membrane-associated biomolecules in various physiological and pathological processes. However, long-term in situ bioimaging on the cell membrane with conventional fluorescent probes leads to diffusion into cells from the membrane surface. Therefore, we herein proposed a de novo strategy to construct an antidiffusion probe by integrating a fluorochrome characterized by strong hydrophobicity and low lipophilicity, with an enzyme substrate to meet this challenge. This precipitating fluorochrome HYPQ was designed by conjugating the traditionally strong hydrophobic solid-state fluorochrome 6-chloro-2-(2-hydroxyphenyl) quinazolin-4(3H)-one (HPQ) with a 2-(2-methyl-4H-chromen-4-ylidene) malononitrile group to obtain closer stacking to lower lipophilicity and elongate emission to the far-red to near-infrared wavelength. As proof-of-concept, the membrane-associated enzyme γ-glutamyltranspeptidase (GGT) was selected as a model enzyme to design the antidiffusion probe HYPQG. Then, benefiting from the precipitating and stable signal properties of HYPQ, in situ imaging of GGT on the membrane was successfully realized. Moreover, after HYPQG was activated by GGT, the fluorescence signal on the cell membrane remained unchanged, with incubation time even extending to 6 h, which is significant for in situ monitoring of enzymatic activity. In vivo testing subsequently showed that the tumor region could be accurately defined by this probe after longterm in situ imaging of tumor-bearing mice. The excellent performance of HYPQ indicates that it may be an ideal alternative for constructing universal antidiffusion fluorescent probes, potentially providing an efficient tool for accurate imaging-guided surgery in the future. [ABSTRACT FROM AUTHOR]