Silica vesicles (SVs) with a diameter of 30 nm and reduced aggregation have been successfully synthesized using mixed triblock copolymer surfactants as the structure-directing agents, tetraethyl orthosilicate and tetrapropyl orthosilicate as mixed silica sources. Silicon phthalocyanine dichloride (SiPC) has been loaded into SV, significantly enhancing the delivery and photodynamic therapy efficiency of SiPC into cancer cells.