Targeted photoredox catalysis in cancer cells

International audienceThese authors contributed equally: Huaiyi Huang and Samya Banerjee Hypoxic tumours are a major problem for cancer photodynamic therapy. Here we show that photo-redox catalysis can provide an oxygen-independent mechanism of action to combat this problem. We have designed a highly oxidative Ir(III) photo-catalyst, [Ir(ttpy)(pq)Cl]PF6 ([1]PF6, ttpy = 4'-(p-tolyl)-2,2':6',2''-terpyridine, pq = 3-phenylisoquinoline), which is photo-toxic towards both normoxic and hypoxic cancer cells. Complex 1 photo-catalytically oxidizes nicotinamide adenine dinucleotide (NADH), an important coenzyme in living cells, generating NAD • radicals with high turnover frequency in biological media. Moreover, complex 1 and NADH synergistically photo-reduce cytochrome c under hypoxia. Densit