Study Of Hemoporfin Photodynamic Effect Mediated By Different Light Sources

Photodynamic therapy(PDT)is based on the interaction of three main components of photochemistry and photophysics:light,photosensitizer and oxygen,using appropriate wavelengths of light to activate the photosensitive drugs.Photodynamic therapy cause local cell death or tissue necrosis.Compared with the traditional treatment,PDT has the advantages of good selectivity,local treatment and quick effect.Hemoporfin(HMME)is a second-generation photosensitizer,which is more stable and less toxic than the first-generation photosensitizer.For different diseases,different light sources are used in clinic,but there is no comparative study on the effectiveness of different light sources.In this study,first,the optical properties of HMME including its characteristic absorption peak wavelength were examined.Then the photodynamic effect of different light sources was analyzed.The light sources tested included:532 nm and 630 nm diode lasers,520-530 nm and 620-630 nm light-emitting diode(LED),560-1200 nm and 640-1200 nm intense pulse light(IPL).The spectrum and spot uniformity of light sources were measured.The photodynamic efficiency was theoretically predicted by comparing the light source spectrum and the absorption spectrum and the extinction coefficient of the center wavelength of the light source.Photobleaching experiments were carried out for each light source.Finally,human skin cancer cells were used to evaluate the effect of different light sources on HMME photodynamic effect.The experimental results showed that all six light sources can produce photodynamic effect in combination with HMME.In terms of cell killing,the photodynamic efficiency of the green light source(532 nm laser and 520-530 nm LED)was relatively higher.