The complex between 9-(n-decanyl)acridone and Bovine Serum Albumin. Part 2. What do fluorescence probes probe?

Abstract

Factor analysis indicates that the fluorescence spectrum of 9-(n-decanyl)acridone (NDA), when bound to Bovine Serum Albumin (BSA), can be described quite adequately as the sum of two spectra, attributed to a "free" and a "bound" species. Kinetic evidence indicates that upon electronic excitation the system undergoes a net increase in free NDA, relative to the equilibrium distribution in the ground state, which would be consistent with Lewis acid sites on BSA being responsible for the binding. The system does not attain a position of equilibrium during the duration of the excited singlet state. This permits the determination of excited state rate constants for binding and unbinding of NDA on BSA, as well as the decay constants for the two forms of the probe.

Tautomerization in the ground and first excited singlet states of phenyl-lapimidazole

“…This observation is in agreement with the factor analysis results of the fluorescence spectra and with the idea that the tautomers do not reach equilibrium during the lifetime of the excited state. The observation of biexponential decays is consistent with both [39] (a) proton transfer being considerably slower than excited state decay (in which case what is really being observed is mono-exponential decay from each species) and (b) excited state proton transfer occurring at a rate analogous to decay (in which case the differential equations which describe the decay of the two species are coupled and each species decays following a bi-exponential). For case a, in the spectral region where only one of the species emits, one should observe mono-exponential decay.…”

Characterization of PLGA Microparticles as a Drug Carrier for 3-Ethoxycarbonyl-2H-Benzofuro[3,2-f]-1-Benzopyran-2-One. Ultrastructural Study of Cellular Uptake and Intracellular Distribution

“…The absorption spectrum of the MPs loaded with psoralen A in solution shows an overlap of bands in the UV region, with considerable light scattering due to the MPs suspended in water. The use of a deconvolution technique (Lunardi et al 2003) minimizes this problem, giving the absorption spectrum of the psoralen A-MP alone (Figure 2). …”

“…The absorption attributed to psoralen A incorporated into the MPs was determined by deconvoluting the absorption spectrum into its three parts using a program based on the self-modeling factor analysis (SM-FA) method to determine the number of components contributing to the absorption spectra and the spectrum of each component (Lunardi et al 2003). These components were glycerol and MP-loaded with psoralen A.…”

Donor-Acceptor Conjugated Linear Polyenes: A Study of Excited State Intramolecular Charge Transfer, Photoisomerization and Fluorescence Probe Properties

“…Most of the known extrinsic fluorescence probes such as ANS [93], Nile red [94], cyanine dye and rhodamine [95], brilliant blue [96], bromocresol purple anion [97], acridone derivatives [98], non-cyanine fluorescence probe [99], etc. are ionic, polar and hydrophilic in nature.…”