Photo-oxidative Stress in the Presence of a Water-soluble Derivative of C60: ESR and AFM Assays

Reactive oxygen species (ROS) are a family of oxygen-based highly reactive molecules, which are implicated in numerous processes of cellular metabolism, where maintaining the redox equilibrium is a prerequisite for normal functioning. Under certain conditions, however, ROS can damage important parts of cells, including proteins, membranes and DNA. At the cellular level, such pathogenic scenario, also called oxidative stress (OS), results from an imbalance between the pro-oxidative capacity of ROS and cell ability to neutralize them with antioxidants. OS-induced cellular damage has been implicated in numerous human pathologies, from brain disorder (like Alzheimer and Parkinson’s diseases), to various forms of cancer (like skin melanoma) and eye pathologies (cataract, macular disease), as well as in the ageing process. OS can also be purposely induced, for e.g. in diseased tissues. This is the basis of a novel therapeutic modality called photodynamic therapy (PDT), which enables one to selectively eradicate diseased cells and tissues. PDT is emerging as a promising therapeutic technique to cure various types of cancer, including skin cancers and is also used in many non-tumor related medical, dermatological and cosmetic applications. To eradicate the diseased tissues, PDT employs tissue-selective light-harvesting molecules, called photosensitizers (PS), and light of the appropriate wavelength.