However, one critical issue that will possibly limit the applications of these photosensitizers
remains to be their intrinsic absorbance wavelength of which light cannot penetrate into deep tissue.
Introduction Natural perylenequinone chemicals such as hypocrellin, cercosporin, erythroaphin, calphostin, hypomycin, phleichrome, and elsinochrome are highly effective photosensitizers
and share common photosensitization mechanisms in photodynamic process _ENREF_1.
Two common photosensitizers
are tolonium chloride and methylene blue.
There results exhibited that HepG2 was resistant to the phototoxic effect of these two photosensitizers
with concentrations up to 4uM and light dose of 40 J/cm2 (Chi-Fung, et al.
8 Third-generation photosensitizers
include currently available drugs that are modified by targeting with monoclonal antibodies or with non-antibody-based protein carriers and protein/receptor systems, and conjugation with a radioactive tag.
The drugs currently used in photodynamic therapy, called photosensitizers
, produce a highly reactive form of oxygen when activated by light.
In the opening chapter of this collection, two pharmacy professors from Charles University in Prague review the history of photodynamic therapy, its photophysical and photochemical principles, and the biological effects of the photosensitizers
Alongside the well-established photosensitizers
such as porphyrins, phtalocyanins and chlorins, hypericin is a modern anticancer drug which exhibits promising photodynamic therapeutical properties.
An example is the application of nanoparticles as photosensitizers
are chemical agents that can kill one-celled organisms when the organisms are exposed to a particular type of light.
It is interesting to note that the photosensitization of diphenyliodonium salt decomposition involving ketones, hydrocarbons, and dyes as photosensitizers
has been found to occur mostly through electron transfer.
Thus, doctors use specific photosensitizers
and wavelengths of light to treat different areas of the body with PDT.