High affinity fluorescently tagged aptamer for EpCam (Kd = 39.42 nM in HT29 cells). Efficiently internalized upon binding to EpCAM. Exhibits rapid penetration of tumorspheres in vitro, as well as superior penetration, accumulation and retention in tumor xenografts in vivo than an antibody to the same target. For optimal binding aptamers require refolding into their tertiary structure prior to use. Please refer to the protocol for information regarding refolding and aptamer use in unfixed cell imaging and flow cytometry. MW (observed): 6782.21.