No abstract

Objective: To construct prostate-specific membrane antigen (PSMA)-targeting, indocyanine green (ICG)-loaded nanobubbles (NBs) for multimodal (ultrasound, photoacoustic and fluorescence) imaging of prostate cancer. Methods: The mechanical oscillation method was used to prepare ICG-loaded photoacoustic NBs (ICG NBs). Then, PSMA-binding peptides were connected to the surface of ICG NBs using the biotin-avidin method to make targeted photoacoustic NBs, namely, PSMAP/ICG NBs. Their particle sizes, zeta potentials, and in vitro ultrasound, photoacoustic and fluorescence imaging were examined. Confocal laser scanning microscopy and flow cytometry were used to detect the binding ability of the PSMAP/ICG NBs to PSMA-positive LNCaP cells, C4-2 cells, and PSMAnegative PC-3 cells. The multimodal imaging effects of PSMAP/ICG NBs and ICG NBs were compared in nude mouse tumor xenografts. Results: The particle size of the PSMAP/ICG NBs was approximately 457.7 nm, and the zeta potential was approximately −23.5 mV. Both confocal laser scanning microscopy and flow cytometry confirmed that the PSMAP/ICG NBs could specifically bind to both LNCaP and C4-2 cells, but they rarely bound to PC-3 cells. The ultrasound, photoacoustic and fluorescence imaging intensities of the PSMAP/ICG NBs in vitro positively correlated with their concentrations. The ultrasound and photoacoustic imaging effects of the PSMAP/ICG NBs in LNCaP and C4-2 tumor xenografts were significantly enhanced compared with those in PC-3 tumor xenografts, which were characterized by a significantly increased duration of ultrasound enhancement and heightened photoacoustic signal intensity (P < 0.05). Fluorescence imaging showed that PSMAP/ICG NBs could accumulate in LNCaP and C4-2 tumor xenografts for a relatively long period. Conclusion: The targeted photoacoustic nanobubbles prepared in this study can specifically bind to PSMA-positive prostate cancer cells and have the ability to enhance ultrasound, photoacoustic and fluorescence imaging of PSMA-positive tumor xenografts. Photoacoustic imaging could visually display the intensity of the red photoacoustic signal in the tumor region, providing a more intuitive imaging modality for targeted molecular imaging. This study presents a potential multimodal contrast agent for the accurate diagnosis and assessment of prostate cancer.

To construct nanobubbles (PTX-AMD070 NBs) for targeted delivery of paclitaxel (PTX) and AMD070, examine their performance in ultrasound molecular imaging of breast cancer and cervical cancer and their therapeutic effect combined with ultrasound targeted nanobubble destruction (UTND). Materials and methods: PTX-AMD070 NBs were prepared via an amide reaction, and the particle size, zeta potential, encapsulation rate and drug loading efficiency were examined. Laser confocal microscopy and flow cytometry were used to analyze the targeted binding ability of PTX-AMD070 NBs to CXCR4 + MCF-7 cells and C33a cells. The effect of PTX-AMD070 NBs combined with UTND on cell proliferation inhibition and apoptosis induction was detected by CCK-8 assays and flow cytometry. The contrast-enhanced imaging features of PTX-AMD070 NBs and paclitaxel-loaded nanobubbles were compared in xenograft tumors. The penetration ability of PTX-AMD070 NBs in xenograft tissues was evaluated by immunofluorescence. The therapeutic effect of PTX-AMD070 NBs combined with UTND on xenograft tumors was assessed. Results: PTX-AMD070 NBs showed a particle size of 494.3±61.2 nm, a zeta potential of −22.4±1.75 mV, an encapsulation rate with PTX of 53.73±7.87%, and a drug loading efficiency with PTX of 4.48±0.66%. PTX-AMD070 NBs displayed significantly higher targeted binding to MCF-7 cells and C33a cells than that of PTX NBs (P<0.05), and combined with UTND manifested a more pronounced effect in inhibiting cell proliferation and promoting apoptosis than other treatments. PTX-AMD070 NBs aggregated specifically in xenograft tumors in vivo, and significantly improved the image quality. Compared with other treatment groups, PTX-AMD070 NBs combined with UTND exhibited the smallest tumor volume and weight, and the highest degree of apoptosis and necrosis. Conclusion: PTX-AMD070 NBs improved the ultrasound imaging effect in CXCR4 + xenograft tumors and facilitated targeted therapy combined with UTND. Therefore, this study provides an effective method for the integration of ultrasound molecular imaging and targeted therapy of malignant tumors.