The fluorescence properties of the aflatoxins M1, Q1, P1 in solution and the effect of various cyclodextrins (alpha-, beta-, gamma-, hydroxypropyl-beta- and alpha-beta-heptakis-di-O-methyl-beta-) on their fluorescence emission were studied. Among the aflatoxins, a substantial enhancement of the fluorescence emission of aflatoxin Q1 in the presence of aqueous solutions of alpha-, beta-, hydroxypropyl-beta, and alpha-beta-heptakis-di-O-methyl-beta-cyclodextrin, was observed. On the contrary, gamma-cyclodextrin proved to be inefficient to enhance the fluorescence properties of this compound. No important fluorescence enhancement was found for aflatoxins P1 or M1 for any of the cyclodextrin derivatives tested. The complex formation constant (Kf) of these compounds with beta-cyclodextrin was chromatographically determined, and from the results obtained, we can conclude that Kf cannot be used alone to explain the fluorescence increase. Thermodynamic studies showed that delta-H and delta-S parameters, associated with the partition of aflatoxins in RP-HPLC, increased when beta-cyclodextrin was added to the eluent.
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http://dx.doi.org/10.1016/s0021-9673(98)00509-3 | DOI Listing |
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January 2025
State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, 750021, China.
Functional polymeric nanoparticles, especially those with anisotropic structures, have shown significant potential and advantages in biomedical applications including detecting, bioimaging, antimicrobial and anticancer. Herein, tetraphenylethylene (TPE) and azobenzene modified polypeptides of poly((-glutamic acid) tetraphenylethylene-stat-(-glutamic acid)) (P(GATPE-stat-GA)) and poly((-glutamic acid) azobenzene-stat-(-glutamic acid)) (P(GAAzo-stat-GA) are synthesized, which self-assemble into bowl-shaped nanoparticles (BNPs) with controlled diameter, opening size and fluorescent property individually, or by co-assembly. Due to the quenching effect of azobenzene, the fluorescence of the coassembled BNPs is completely inhibited.
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January 2025
Kyoto University: Kyoto Daigaku, Graduate Schools of Pharmaceutical Sciences, 46-29, Yoshidashimoadachi-cho, Sakyo-ku, 606-8501, Kyoto, JAPAN.
Novel circularly-polarized-luminescence (CPL) materials were designed and synthesized by integrating the intrinsic chirality of helicene with the acid/base-responsive properties of fluorescein. The synthesized helicene-fluorescein hybrids exhibit reversible switching between blue fluorescence under neutral conditions and red fluorescence under basic conditions. Furthermore, these hybrid compounds demonstrate unique chiroptical switching behavior with a rare base-triggered CPL sign inversion, where (P)-isomers show a negative CPL signal around 450 nm under neutral conditions and a positive signal around 620 nm under basic conditions, with three-fold enhanced dissymmetry factors (|glum|) under basic conditions.
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January 2025
The University of Arizona, Chemistry and BioChemistry, 1306 E University Blvd, CSML 638, 85719, Tucson, UNITED STATES OF AMERICA.
Fluorination of tris(2,6-dimethoxyphenyl)-methylium ((DMP)3C+) was achieved through the partial defluorination of the methyl 2,3,5,6-tetrafluorobenzoate via nucleophilic aromatic substitution. Using the fluorinated 2F((DMP)3C+) as a precursor, fluorinated tetramethoxy- and dimethoxyquin- acridinium salts (2F4 and 2F5 respectively) and trioxo-, azadioxo-, and diazaoxo- triangulenium salts (2F6, 2F7 and 2F8 respectively) were synthesized successfully in good to moderate yields. Fluorination induced significant red shifts in absorption (16 to 29 nm) and emission (13 to 41 nm) maxima, and increased electrophilicity as evidenced by lower reduction potentials.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, China.
Adenosine triphosphate (ATP) is a critical intracellular energy currency that plays a key role in various cellular processes and is closely associated with numerous diseases. Similarly, biothiols such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) are integral to many physiological and pathological processes due to their strong redox properties. Simultaneous discrimination and detection of ATP and biothiols offer valuable insights into the pathogenesis of conditions such as epilepsy and liver injury.
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January 2025
Visvesvaraya National Institute of Technology, Chemistry, Visvesvaraya National Institute of Technology, South Ambazari Road, 440010, India, 440010, Nagpur, INDIA.
Thermally activated delayed fluorescence (TADF) has recently emerged as a promising process with significant potential to advance organic light-emitting diodes (OLEDs) for display applications. The donor-acceptor system is a well-known molecular arrangement exhibiting TADF properties. However, our investigation into the chalcone-based donor-π-acceptor (D-π-A) system (SKG1) reveals that the en-one bridging unit in chalcone plays a crucial role in the reverse intersystem crossing (rISC) process and may be responsible for the existence of two conformational isomers.
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