Cellular Synthesis of Targeted Ultrasound Molecular Imaging Probe and Its Application in Prostate Cancer Diagnosis.

Purpose: The traditional construction of targeted ultrasound molecular imaging probes relies on multistep chemical synthesis strategies, which are time-consuming and inefficient, thereby limiting technological advancements. To address this, we developed a novel genetic engineering approach for biosynthesizing targeted nanoprobes for prostate cancer diagnosis. Materials and Methods: The anti-PSMA nanobody-encoding gene was fused to the C-terminus of the gas vesicle structural protein gene GvpC and cloned into a pBV220 plasmid with a hyperthermia-responsive gene expression circuit. This recombinant plasmid was transformed into E. coli BL21(A1) harboring pET-28a-ΔGvpC-eGVs plasmids to create PSMA-GVs@E. coli genetically engineered bacteria. The probe assembly were involved in two-step gene expression procedure. ΔGvpC-eGVs were first induced by IPTG, followed by temperature-triggered (42°C) production of PSMA-GvpC proteins that spontaneously assembled onto GVs. Results: The biosynthesized PSMA-eGVs probes exhibited a uniform size (100-200 nm) and demonstrated excellent targeting capability in prostate cancer cells. In vivo studies confirmed effective tumor vascular penetration and specific binding with PSMA-positive tumor cells, resulting in significantly stronger acoustic signals than the non-targeted EGFP-eGVs controls. Conclusion: This cellular synthesis strategy enables efficient production of targeted ultrasound molecular imaging probes through genetically engineering technology, providing a promising platform for precision cancer diagnostics.