Phototoxicity of Some Bromine‐Substituted Rhodamine Dyes: Synthesis, Photophysical Properties and Application as Photosensitizers

Abstract

The synthesis of some bromine-substituted rhodamine derivatives viz., 4,5-dibromorhodamine methyl ester (dye 2) and 4,5-dibromorhodamine n-butyl ester (dye 3) are reported. These dyes were synthesized to promote a more efficient cancer cell photosensitizer for potential use in in vitro bone marrow purging in preparation for autologous bone marrow transplantation. Spectroscopic and photophysical characterization of these dyes together with rhodamine 123 (dye 1) are reported in water, methanol, ethanol and also in a microheterogeneous system, sodium dodecyl sulfate. The possible mechanism of photosensitization is characterized in terms of singlet oxygen efficiency of these dyes. Singlet oxygen quantum yields for bromine-substituted dyes are in the range of 0.3-0.5 depending on the solvent. For dye 1 no singlet oxygen production is found. The photodynamic actions of these dyes in different cell lines are tested. It was found that dye 2 and dye 3 are efficient photosensitizers and mediate eradication of K562, EM2, myeloid cell lines (CML) and the SMF-AI rhabdomyosarcoma line.

Interaction of Chlorpromazine and Trifluoperazine with Anionic Sodium Dodecyl Sulfate (SDS) Micelles: Electronic Absorption and Fluorescence Studies

“…Similar aggregation phenomena were observed with cationic rhodamine dyes in the presence of anionic SDS and D,L-α-dipalmitoyl phosphatidyl-L-serine (DPPS) (4,40) as well as for the anionic form of another compound, 2,4,6-trichlorophenol, upon interaction with cationic cetyltrimethylammonium chloride (CTAC) micelles (33) absorbance in this premicellar region (just below the normal CMC) showing that the presence of premicelles provides the drug with the micellar-like environment. Upon further increase of [SDS], the absorbance (Fig.…”

Surface-Enhanced Raman Scattering of Rhodamine 123 in Silver Hydrosols and in Langmuir–Blodgett Films on Silver Islands

“…In aqueous solution it has an absorption maximimum at 498 nm and the corresponding emission maxima is at 525 nm (11). It is difficult to obtain its resonance Raman spectrum (RRS) due to the strong fluorescence background.…”

Selenorhodamine photosensitizers with the Texas-red core for photodynamic therapy of cancer cells

“…6 Unfortunately, rhodamine-123 and related compounds absorb wavelengths of light too short for effective penetration of tissue (k max 500-550 nm) and generate singlet oxygen ( 1 O 2 ) and other reactive oxygen species inefficiently. To circumvent these shortcomings, rhodamine derivatives bearing bromine as a heavy atom 7 were prepared and were shown to have increased quantum yields for the generation of 1 O 2 [U( 1 O 2 )] and still targeted the mitochondria, but values of k max were essentially unchanged and were still in the 500-550-nm window. [8][9][10] We have incorporated selenium as a heavy atom in the chalcogenoxanthylium core of the rhodamines, which has given bathochromic shifts in k max and values of U( 1 O 2 ) of up to 0.87 for the selenorosamine TMR-Se (Chart 1).…”