Probing the structure of 'hematoporphyrin derivative' via fluorescence and absorbance spectroscopy.

Abstract

Spectral properties of the tumor-localizing dimer/oligomer fraction of HPD and of several diporphyrin ethers were assessed by fluorescence and absorbance spectroscopy in different solvents and after accumulation by leukemia L1210 cells in vitro. Joining 2 porphyrins by an ether linkage caused a blue shift in the Soret bands of the dimers, but not monomers, when the dielectric constant of the solvent was lowered. The presence of ether linkages was assciated with enhanced fluorescence at 630-640 nm and decreased fluorescence lifetimes and fluorescence yields. The joining of two mesoporphyrin or protoporphyrin mole cules by an ether linkage reduced dye accumulation by L1210 cells, but makedly promoted uptake of the hematoporphyrin analog.