Co-delivery of nucleic acids and chemotherapeutics has the potential to efficaciously treat human diseases via their synergetic effects.Here,a gold nanocages(AuNCs)based drug/miRNA co-delivery system was designed and fabricated to co-deliver doxorubicin(Dox)and anci-miR-181b for efficient cancer therapy.Firstly,AuNCs were modified with 11-Mercaptoundecanoic acid(MUA)through the bond of Au-S,so that DOX can be loaded into the inner of the MUA-coated AuNCs.Then,the outside surfaces of the Dox-loaded AuNCs were modified with polyethyleneimine in order to combine miRNA.