70 research outputs found
The influence of lead (II) ions introduced into the subphase on the stability of mixed "polyamic acid + surfactant" monolayers and manufacturing of dye-containing Langmuir-Blodgett polymeric films
A Dual FluorescenceâSpin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIMâEPR Spectroscopy
Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching. Here, we solved this problem and present the molecular design of a dual label (DL) compound comprising a highly fluorescent dye together with an EPR spin probe, which also renders the fluorescence lifetime to be concentration sensitive. The DL can easily be coupled to the biomolecule of choice, enabling inâ
vivo and inâ
vitro applications. This novel approach paves the way for elegant studies ranging from fundamental biological investigations to preclinical drug research, as shown in proof-of-principle penetration experiments in human skin exâ
vivo
Comparative Analysis of the Antineoplastic Activity of C60 Fullerene with 5-Fluorouracil and Pyrrole Derivative In Vivo
The Nature of Aqueous Solutions of a Cationic Calix[4]arene: A Comparative Study of DyeâCalixarene and DyeâSurfactant Interactions
Among different types of calixarenes, the waterâsoluble ones are of especial interestbecause of their possible applications in biochemical research. In order to elucidate the natureof aqueous solutions of a cationic amphiphilic calixarene, substituted tetrapropoxycalix[4]arene bearing hydrophilic choline groups at the upper rim, we studied visâspectroscopically the influence of the above system on the acidâbase behavior of threeindicator dyes, namely, 2,4-dinitrophenol, bromophenol blue, and N,N/-dioctadecylrhodamine,at constant ionic strength of 0.05 M, maintained with NaCl addition. Simultaneously,âapparentâ ionization constants, Kaa , of the same dyes were determined in the presence ofcommon cationic surfactant micelles. Within the concentration range from 1.0Ă10â5 to 0.01 M,the aforementioned waterâsoluble calixarene displays effects similar to those of micelles ofcetyltrimethylammonium bromide (or chloride). The shifts of the absorption and emissionbands in the visible region, as well as the alterations of the Kaa values against the âaqueousâones appeared to be very similar in aqueous solutions of both calix[4]arene and cationicsurfactant. A conclusion can be made about aggregation (or association), i.e., micelleformation of the cationic calix[4]arene under study
Absorption, fluorescence, and acid-base equilibria of rhodamines in micellar media of sodium dodecyl sulfate
The Nature of Aqueous Solutions of a Cationic Calix[4]arene: A Comparative Study of DyeâCalixarene and DyeâSurfactant Interactions
Effect of the solvent on the absorption spectra and protonation of fluorescein dye anions
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