Scheme 1.
Schematic illustration of two-photon-activated photodynamic therapy (TPA-PDT) using mesoporous silica-encased gold nanorods. Pd-porphyrins (Green sphere), conjugated onto the walls of nanochannels within the mesoporous silica shell, are activated via intra-particle plasmonic energy transfer (ET) from two-photon-excited gold nanorods, to generate cytotoxic singlet oxygen.