Targeted Biosynthetic Nanobubbles for Ultrasound Molecular Imaging of Prostate Cancer.

Abstract

Objective: As the second leading cause of cancer-related mortality in males worldwide, prostate cancer (PCa) presents an urgent need for advanced molecular imaging strategies to improve diagnostic precision. This study presents CD147-targeted nanobody-conjugated biosynthetic gas vesicles (CD147-hGVs) as a high-performance ultrasound molecular imaging probe for precise and noninvasive diagnosis of PCa.

Methods: Biosynthetic gas vesicles (hGVs) were site-specifically functionalized with anti-CD147 nanobodies via controlled maleimide-thiol conjugation chemistry using Mal-PEG2000-NHS heterobifunctional crosslinkers. Systematic characterization included stability assessments, in vitro targeting validation (flow cytometry, cell adhesion, and immunofluorescence on PC-3 cell lines), and in vivo ultrasound imaging in PCa-bearing nude mice using Clinical ultrasound diagnostic equipment Mindray Resona 9T.

Results: CD147 -hGVs exhibited remarkable stability with sustained monodispersity (PDI <0.2) and consistent hydrodynamic diameter (234.4 ± 7.6 nm at day 1 vs 236.0 ± 9.8 nm at day 10, p = 0.32). In vitro targeting assays revealed about 7-fold higher binding affinity of CD147-hGVs to PC-3 cells compared to non-targeted controls (p < 0.001). In vivo molecular ultrasound imaging showed tumor-specific signal enhancement persisting for >15 min post-injection, with CD147-hGVs achieving about 6-fold higher contrast to Con-hGVs (p < 0.01).

Conclusion: Anti-CD147 nanobody conjugated biological gas vesicles exhibit excellent stability and enhanced targeting ability for prostate cancer cells, making them a promising novel molecular probe for ultrasound imaging and potential therapy for prostate cancer.