Xinyang Normal University 1 article published in JoVE Chemistry Synthesis of Aptamer-PEI-g-PEG Modified Gold Nanoparticles Loaded with Doxorubicin for Targeted Drug Delivery Lei Nie1,2, Shaolan Sun1, Meng Sun1, Qiuju Zhou3, Zongwen Zhang3, Lingyun Zheng3, Lingling Wang3 1College of Life Sciences, Xinyang Normal University, 2Department of Imaging & Pathology, University of Leuven and Oral & Maxillofacial Surgery, University Hospitals Leuven, 3Analysis & Testing Center, Xinyang Normal University In this protocol, doxorubicin-loaded AS1411-g-PEI-g-PEG modified gold nanoparticles are synthesized via three-step amide reactions. Then, doxorubicin is loaded and delivered to target cancer cells for cancer therapy.