SYL3C Aptamer-DNA Tetrahedra Conjugates Enable Near-Infrared Fluorescent Imaging of Colorectal Cancer

Zhidie Huang,1 Pinghui Li,1 Yiwen Li,1 Xiaoyan Duan,2,3 Mengting Li,4,5 Dawei Jiang,4,5,* Jianbo Li2,3,* 1Inner Mongolia Medical University, Hohhot, People’s Republic of China; 2Department of Nuclear Medicine, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot, People’s Republic of China; 3Inner Mongolia Key Laboratory of Molecular Imaging, Hohhot, People’s Republic of China; 4Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China; 5Hubei Province Key Laboratory of Molecular Imaging, Wuhan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jianbo Li, The Affiliated Hospital of Inner Mongolia Medical University, 010050, Email [email protected] Dawei Jiang, Huazhong University of Science and Technology, 430022, Email [email protected]: SYL3C is an optimized DNA aptamer with high selectivity and affinity for the epithelial cell adhesion molecule (EpCAM), an overexpressed tumor antigen in colorectal cancer (CRC). While its cellular affinity has been validated, in vivo studies are lacking.Methods: This study modifies SYL3C with the fluorescent motif Cy7 to evaluate its metabolism and diagnostic potential in EpCAM-positive HT-29 xenograft mice using near-infrared fluorescence (NIRF). We also employ DNA Tetrahedra (DTN) to load the Cy7-DTN-SYL3C probe and assess whether this strategy improves circulation and tumor uptake of SYL3C.Results: Cy7-SYL3C is primarily metabolized by the kidneys and enables targeted imaging of HT-29 tumors, outperforming untargeted Cy7-DTN. The DTN coupling strategy prolongs SYL3C metabolism and enhances tumor probe uptake about twice higher than Cy7-SYL3C over 24 hours.Conclusion: This study presents preliminary evidence for the SYL3C aptamer’s potential in vivo imaging of EpCAM-positive CRC. The DTN conjugation strategy may extend the aptamer’s metabolic stability and improve tumor uptake, expanding its applications in CRC diagnosis and treatment. Keywords: epithelial cell adhesion molecule, aptamer, nanomaterial, molecular imaging, tumor