Synthesis of fluorinated triphenylphosphonium analogs that improve cancer cell selectivity and in vivo detection

Triphenylphosphonium (TPP(+)) compounds like mito-metformin (MMe) target cancer cells by exploiting their hyperpolarized mitochondrial membrane potential. Here, we present a protocol for synthesizing TPP(+) analogs with selectivity for mammalian cancer cells, reduced toxicity, and quantifiability using fluorine-19 nuclear magnetic resonance ((19)F-NMR). We describe steps for treating mammalian cells with mitochondria-targeted compounds, treating and preparing mouse tissue with these compounds, and (19)F-NMR detection of MMe analogs in cells and tissue. TPP(+)-conjugated metformin analogs include para-methoxy (pMeO-MMe) and para-trifluoromethyl MMe (pCF(3)-MMe) and meta-trifluoromethyl MMe (mCF(3)-MMe).