We previously showed that semiconducting single-walled carbon nanotubes are able to generate reactive oxygen species under near-infrared (NIR) illumination for the elimination cancer cells (J. Am. Chem. Soc. 2012, 134, 17862–17865), and a heavy metal ion-coordinated naphthalocyanine dimer was found to be a NIR dye capable of highly-sustained photothermal activity thanks to its unique structure (ACS Nano 2013, 7, 8908–8916). We also succeeded in developing a photo control method for plasma membrane potential by utilizing long-lived charge separation states of fullerene derivatives (J. Am. Chem. Soc. 2012, 134, 6092–6095), and extremely localized photothermal heating system by using gold nanorods and NIR laser (ACS Nano 2014, 8, 7370–7376). In all these cases, genetically and/or chemically engineered high-density lipoprotein (HDL) mutants (Biotechnol. J. 2012, 7, 762–767) were the key nanomaterials that enabled stabilization, detoxification, and site-specific delivery of the NIR-responsive nanomaterials.
HDL is a natural nanomaterial, consisting mainly of a lipid-binding serum protein, apoA-I and phospholipids, that mediates reverse cholesterol transport in our bodies, in other words, the good cholesterol. Recent studies have revealed broader functions of HDL, such as glucose metabolism acceleration and microRNA transport. In collaboration with medical and pharmaceutical research groups in Kyoto University and ETH Zürich, we are also developing HDL-based drug carriers by utilizing protein-engineering approaches.