Preclinical Evaluation of a PSMA Aptamer-Based Bifunctional PET and Fluorescent Probe

Prostate cancer is the most prevalent malignant tumor affecting male individuals worldwide. The accurate early detection of prostate cancer is crucial to preventing unnecessary diagnosis and subsequent excessive treatment. Prostate-specific membrane antigen (PSMA) has emerged as a promising biomarker for the diagnosis of prostate cancer. In this study, a dual-modality imaging probe utilizing aptamer technology was developed for positron emission tomography/near-infrared fluorescence (PET/NIRF) imaging, and the specificity and sensitivity of the probe toward PSMA were evaluated both in vitro and in vivo. The probe precursor NOTA-PSMA-Cy5 was synthesized via automated solid-phase oligonucleotide synthesis. Subsequently, the PET/NIRF dual-modality probe [⁶⁸Ga]Ga-NOTA-PSMA-Cy5 was successfully prepared and exhibited favorable fluorescence properties and stability in vitro. The binding specificity of [⁶⁸Ga]Ga-NOTA-PSMA-Cy5 to PSMA was assessed through flow cytometry, fluorescence imaging, and cellular uptake experiments in LNCaP cells and PC-3 cells. In vivo PET/NIRF imaging studies demonstrated the sensitive and specific binding of [⁶⁸Ga]Ga-NOTA-PSMA-Cy5 to PSMA. Overall, the PET/NIRF dual-modality probe [⁶⁸Ga]Ga-NOTA-PSMA-Cy5 shows promise for the diagnosis of prostate cancer and for the fluorescence-guided identification of PSMA-positive cancer lesions during surgical procedures.