Controlled in-cell release of caspase from photodegradable nanoparticles using the PARCEL method

Although local protein activity in the cells is one of the hot topics in life science study, it still presents many difficulties with regard to measuring or changing its activity. Here, we prepared 20 nm-sized protein (caspase)-encapsulated photodegradable nanoparticles and used them to control the amount of caspase released within HeLa cells. Encapsulated caspase was released into the cytosol following irradiation. The increased amount of released caspase led to enhanced cell membrane permeability. These results indicate that the amount of protein released within cells can be regulated by the amount of protein-encapsulated nanoparticles; therefore, this technique would be useful for detailed study of protein function within cells or the control of cellular functions.