Cancer killing catalysts
Nanophotocatalysts are killing cancer and viruses by producing destructive oxygen species.
A system where photostable hexa(sulfo-n-butyl)fullerene (FC4S) nanospheres convert light energy into either 'hot' electrons or triplet energy was developed by Long Chiang from the University of Massachusetts, US, and colleagues from the University of Toronto, Canada, and Tohoku University, Japan. These electron or energy forms then pass to molecular oxygen and form a superoxide radical or singlet oxygen, respectively.
Under photodynamic therapy (PDT) treatment, production of these reactive oxygen species can destroy tumour and cancer cells such as fibrosarcoma tumour cells. The fullerene C60 molecule is a good choice for PDT treatment because it generates triplet energy quantitatively. The C60 was tuned for biological applications by adding micelles to make it less hydrophobic.
FC4S compares favourably with other PDT drugs and has the added advantage of being photostable. This means a single dose might be possible for multiple treatments.
Following the success of this research, Chiang hopes the principle will be applied elsewhere, for example in cosmesis or other environmental applications such as antibacterial spray and water treatment.