Enhanced NIR-II Nanoparticle Probe for PSMA-Targeted Molecular Imaging and Prostate Cancer Diagnosis

Abstract

Zhongji Jiang,1,2 Jin Zhang,3 Jiali Jin,3 Xun Zhang,4 Gaohaer Kadeerhan,5 Hong Guo,3 Dongwen Wang2,6 1Department of Biology, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, People’s Republic of China; 2Department of Urology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong, 518116, People’s Republic of China; 3Department of Urology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030001, People’s Republic of China; 4Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, People’s Republic of China; 5Central Laboratory, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong, 518116, People’s Republic of China; 6School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, People’s Republic of ChinaCorrespondence: Dongwen Wang, Email [email protected]: Prostate-specific membrane antigen (PSMA) is a well-established biomarker overexpressed in prostate cancer (PCa). However, existing PSMA-targeted imaging probes suffer from radiation exposure, limited tissue penetration, and inadequate intraoperative performance. To overcome these challenges, we developed a novel near-infrared-II (NIR-II) fluorescent nanoprobe for both in vivo and ex vivo imaging of PCa.Methods: An organic semiconducting polymer (OSP12) with strong NIR-II fluorescence and excellent photostability was self-assembled into nanoparticles (NPs) using DSPE-PEG-Mal. These OSP12 NPs were then conjugated with ACUPA-SH, (S)-2-[3-((S)-5-amino-1-carboxypentyl)ureido]pentanedioic acid, a thiol-modified glutamate-urea-lysine derivative that specifically targets PSMA, via a maleimide-thiol click reaction to form PSMA-OSP12 NPs. The probe’s targeting specificity was assessed using PSMA positive and negative cell lines under NIR-II imaging. For in vivo evaluation, subcutaneous xenograft tumors were established in BALB/c nude mice. Animals were randomly assigned to PSMA-OSP12 NP, blocking (ACUPA pre-injection), and control (OSP12 NPs) groups (n = 3 per group). Ex vivo tumor slice imaging was performed on fresh tissue sections. Biosafety was evaluated in healthy mice (n=5) through hematological, biochemical, and histopathological analyses.Results: PSMA-OSP12 NPs exhibited excellent optical properties in the NIR-II window, including high photostability, negligible autofluorescence, and deep tissue penetration. In vitro assays confirmed selective binding to PSMA-positive cells, while in vivo imaging demonstrated sustained tumor accumulation with a peak TBR of 7.40 ± 1.28 at 48 h post-injection. This performance significantly surpassed OTL78 and Cy-KUE-OA, enabling flexible surgical planning and real-time intraoperative guidance. In ex vivo tissue imaging, PSMA-OSP12 NPs provided high-contrast tumor delineation without systemic administration. Biosafety evaluations revealed no significant systemic toxicity, and biodistribution analysis indicated hepatic metabolism and biliary clearance.Conclusion: PSMA-OSP12 NPs are a promising NIR-II fluorescent probe with excellent tumor specificity, deep tissue imaging capability, and good biocompatibility, supporting their application in fluorescence-guided surgery and ex vivo tumor evaluation.Keywords: prostate cancer, prostate-specific membrane antigen, NIR-II, fluorescence-guided surgery, tumor targeting, molecular imaging, organic semiconducting polymer, nanoparticles

Keywords

• Prostate cancer
• Prostate-specific membrane antigen
• NIR-II
• Fluorescence-Guided Surgery
• Tumor targeting
• Molecular imaging