In one aspect, a composition can include an organelle, and a nanoparticle having a zeta potential of less than -10 mV or greater than 10 mV contained within the organelle. In a preferred embodiment, the organelle can be a chloroplast and the nanoparticle can be a single-walled carbon nanotube associated with a strongly anionic or strongly cationic polymer.
 This invention was made with Government support under Grant No. DBI-1103600 awarded by the National Science Foundation and under Contract No. DE-FG02-08ER46488 awarded by the Department of Energy. The government has certain rights in the invention.