•Two novel fluorescent ethidium derivatives, MTP1 and MTP2 were prepared for selective cancer theranostics.•Cell mitochondria depolarization and a series of cascaded biochemical effects were induced by these ethidium derivatives.•Both MTP1 and MTP2 presented good cancer cell targeting, mitochondria targeting and imaging abilities.•Both MTP1 and MTP2 exhibited good anti-cancer efficiency with no obvious systemic cytotoxicity.In this study, we reported on two novel fluorescent ethidium derivatives of MTP1 and MTP2 for selective and efficient cancer therapy. MTP1 and MTP2 exhibited cancer cell targeting and subsequent mitochondria targeting and imaging abilities. Moreover, both MTP1 and MTP2 would induce mitochondria depolarization and so along with a series of cascaded biochemical effects including the reduction of ATP production, destruction of intracellular redox potential balance and release of mitochondria cytochrome C (Cyt C), which could finally trigger caspase-dependent cell apoptosis. More interestingly, both MTP1 and MTP2 demonstrated significant cancer suppression abilities in vitro and in vivo, which presented a new paradigm for the development of unique anti-cancer agent candidates in precise and efficient cancer theranostics.Download high-res image (182KB)Download full-size image

A six-residue facial cyclopeptide was designed with the following sequence: c-[D-Leu-L-Lys-D-Ala-L-Lys-D-Leu-L-Gln] (CP). Extensive hydrogen bonding between the cyclopeptide backbones mainly regulated CP to self-assemble into single-walled nanotubes. Simultaneously, the hydrophobic interaction among facial hydrophobic side chains of CP was introduced to stabilize the hydrogen bonding, resulting in the formation of the thick-walled nanotubes with high length–diameter ratios.