The effects of pH value and presence of serum in an incubation medium on photosensitizer drug cellular uptake in MCF7 cancer cells have been investigated. The results showed that the presence of serum in an incubation medium reduced the drug cellular uptake at all pH values. It has been found that decreasing on pH values of the incubation medium increased the cellular uptake of the drug, demonstrating selective uptake of the sensitizer. The HepG2 liver cancer cells exhibited more drug cellular uptake than CCD-18CO normal colon cells, which assessed the selectivity uptake of photosensitizer on cancerous cells. The concentration of photosensitizer measured in 10(6) cells showed a good correlation to the incubation time. Fluorescence and absorption spectroscopy been have used to examine the cells.

Melanin is investigated as a pigment that is responsible for colorization in human skin. The color of human skin varies from dark brown to nearly colorless "pinkish white". The amount of skin melanin in the individual skin depends on both genetic and environmental factors. This offers some protection against the damaging effects of ultraviolet radiation. For the studies of laser effects on the skin melanin, the suitable sample is chosen depends on the availability for getting the sample and also the existence of skin melanin on that sample. Therefore, the skin of laboratory rat is used as an experimental sample. Carbon dioxide laser is used as a source of radiation in this study because of its 10.6μm of wavelength which has an ability to penetrate effectively on soft tissue that contains 90% of water. The rat skin is exposed to carbon dioxide laser "CO 2 laser" radiation and any changes on the skin is observed and analyzed. After the exposure, the pieces of normal and exposed skin are preserved. In order to go through the sample, histological method is carried out to make the standard slides for examination under the compound light microscope. The images obtained on the both skin sample the normal and the exposed skin show that there are changes in both skin structures which can be seen clearly under the microscope lenses. These changes contributed by the interaction of the skin cells to the heat and energy produced by the carbon dioxide laser "CO 2 laser" during the exposure time.

Chlorins are potential photosensitizers for photodynamic therapy because of their intense absorption in the red spectral region. In this study, the effect of pH on the absorption and fluorescence of Sn(IV) chlorin e6 dichloride trisodium salt was investigated. Absorption, fluorescence emission and fluorescence excitation spectra of the photosensitizer were recorded at different pH values in an analytical buffer solution with and without fetal bovine serum (FBS). In the neat buffer solution, changing the pH resulted in small shifts in both absorption and emission spectra. The shape of the excitation spectra also changed slightly, with shoulders almost vanishing below pH 5. Also, a pronounced reduction of the fluorescence intensity was observed upon acidification. The fluorescence intensity gradually decreased as the concentration of FBS was increased without shifting fluorescence maxima. The absorbance of the photosensitizer in different solvents was recorded and revealed that Sn(IV) chlorin e6 is highly soluble in polar solvents.