Fluorescent probes for cancer detection.

Several new fluorescent dyes, derivatives of pyrene and of coumarin, were synthesized that have excitation and emission wavelength maxima considerably red-shifted as compared to most pyrene and coumarin compounds. These new fluorescent compounds have high extinction coefficients and high quantum yields, and they also are very environmentally sensitive, which makes them good probes of biological systems. Several of these fluorescent compounds are preferentially taken up and retained by leukemic and other cancer tissue cell lines as compared to normals, particularly 1,3-dihydroxy 6,8-pyrenedisodiumsulfonate and 3-(carboxymethylester)-7-julolidinocoumarin.

Tumor cell specific dark cytotoxicity of light-exposed merocyanine 540: implications for systemic therapy without light.

Merocyanine 540 (MC540) was activated by exposure to 514 nm laser light. The light-exposed MC540 was then mixed (in the dark) with tumor cells and normal cells to determine the antiproliferative activity. Treatment with light-exposed MC540 resulted in 70-90% tumor cell kill from different cell lines, while 85% of the normal human mononuclear cells and 41% of the granulocyte-macrophage colony forming cells (CFU-GM) survived the treatment.

Fluorescent cationic probes of mitochondria. Metrics and mechanism of interaction.

Mitochondria strongly accumulate amphiphilic cations. We report here a study of the association of respiring rat liver mitochondria with several fluorescent cationic dyes from differing structural classes. Using gravimetric and fluorometric analysis of dye partition, we find that dyes and mitochondria interact in three ways: (a) uptake with fluorescence quenching, (b) uptake without change in fluorescence intensity, and (c) lack of uptake.

Increased survival of normal cells during laser photodynamic therapy: implications for ex vivo autologous bone marrow purging.

Laser light-induced, dye-mediated photolysis of leukemic cells was tested in an in vitro model for its efficacy in eliminating occult tumor cells for ex vivo autologous bone marrow purging. Merocyanine 540 (MC540) was mixed with acute promyelocytic leukemia (HL-60) cells in the presence of human albumin. This cell-dye mixture was irradiated with 514 nm argon laser light.