ABSTRACT
The interactions of two metal-free phthalocyanines [(H2Pc) and Solar Pc (with four peripherical groups: SO2N(CH2CH2OH)2)] and of one metal substituted dye (CoPc) with resting and stimulated human peripheral blood mononuclear cells (PBMC) were compared. The absorption, fluorescence, photoacoustic and EPR spectra of both resting cells and cells stimulated by phytohaemagglutinin, incubated in dimethyl sulfoxide (DMSO) with very low or 95% water content and with or without dye addition, were measured. The fate of the light absorbed by the samples was investigated. It is known that singlet oxygen production is crucial for photodynamic action of dyes. Thermal deactivation and luminescence emission compete with this process, so investigation of these alternative paths of sensitizer deactivation provides information about photodynamic action. The incorporation of the investigated dyes into cells and the perturbation of the cell structure caused by the dyes, the incubation solvent and the activator were investigated by comparing the spectral properties of PBMC before and after stimulation and incubation. Incubation of the cells for 1 h in a solution of Solar Pc in 99.5% aqueous DMSO, resulted in an efficient dye incorporation which was highly selective. Solar Pc being introduced much more efficiently into stimulated cells than into resting cells.
Subject(s)
Indoles/chemistry , Indoles/metabolism , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/metabolism , Radiation-Sensitizing Agents/chemistry , Radiation-Sensitizing Agents/metabolism , Electron Spin Resonance Spectroscopy , Flow Cytometry , Hot Temperature , Humans , Isoindoles , Kinetics , Light , Models, Chemical , Protein Binding , Spectrometry, Fluorescence , Spectrophotometry , Time FactorsABSTRACT
Absorption and magnetic circular dichroism (MCD) spectra are reported for chlorophyll (Chl) a and Chl b dissolved in nematic liquid crystal solvents. The spectra were measured with the dye molecules oriented uniaxially along the direction of. the magnetic field and measuring light beam. It is significant that under such conditions the MCD spectra recorded in the wavelength region of the Q and Soret bands of the chlorophyll are essentially unchanged with respect to rotation of the sample cell around this axis, even though there is almost complete orientation of the chlorophyll molecules by the liquid crystals. The MCD spectra of Chl a and b in the nematic liquid crystal solvents used in this study are surprisingly similar to the spectra obtained under isotropic conditions. These results illustrate an important technique with which to examine the optical spectra of dyes oriented in liquid crystal matrices in which the anisotropic effects can be reduced the negligible proportions by the application of a strong magnetic field parallel to the direction of the measuring light beam. The first deconvolution calculations are reported that describe the deconvolution of pairs of absorption and MCD spectra, in the Q and B band regions, for both Chl a and b. The spectral analysis to obtain quantitative estimates of transition energies was accomplished by carrying out detailed deconvolution calculations in which the both the absorption and MCD spectral envelopes were fitted with the same number of components; each pair of components had the same hand centres and bandwidth values. This procedure resulted in an assignment of each of the main transitions in the absorption spectra of both Chl a and b. Chl a is clearly monomeric, with Qy, Qx, By and Bx located at 671, 582, 439 and 431 nm, respectively. Analysis of the spectral data for Chl b located Qy, By and Bx, at 662, 476 and 464 nm, respectively.
