Cu-Labeled Aptamers for Tumor-Targeted Radionuclide Delivery.

Aptamers are a class of oligonucleotides with high binding affinity and specificity with their targets. Additionally, aptamers are nontoxic, very thermally stable, and able to reversibly undergo denaturation and have a small size. Cancer-related aptamers can be used for tumor-targeted drug delivery, such as to deliver diagnostic and therapeutic radionuclides to target cancers. We describe the process for preparing a Cu-labeled modified A10 aptamer to target prostate cancer by conjugating and radiolabeling. The modified A10 aptamer was conjugated with p-SCN-Bn-NOTA as the chelator. Following this, the aptamer can be radiolabeled with the Cu radioisotope. NOTA was selected as the chelator of choice due to its commercial availability and widely demonstrated in vivo stability with the Cu radioisotope. Using this system, prostate cancer could potentially be targeted for noninvasive imaging using positron emission tomography (PET). Closely following this protocol allows many aptamers to be successfully radiolabeled to accurately and quantitatively trace their distribution in vivo for a wide range of medical applications.