对比液态氟碳脂质纳米粒与全氟丙烷脂质微泡体外显影及耐声压性

Comparison of contrast imaging characteristic and acoustic pressure resistance between perfluorooctylbromide lipidic particles and C3F8 lipidic microbubbles in vitro

目的与全氟丙烷(C3F8)脂质微泡造影剂比较,分析自制液态氟碳(PFOB)脂质纳米粒体外显影及耐声压性的优劣。方法分别制备生物素化PFOB脂质纳米粒及生物素化C3F8脂质微泡,评估其稳定性,并观察其加入亲和素前后的体外显影效果。对2种造影剂在低声压(MI=0.28)及高声压(MI=0.56)环境下进行超声辐照,于辐照前及辐照10、20、30 s后观察显影情况及其差异。结果 2种造影剂加入亲和素后均发生聚集现象,粒径均较加入亲和素前明显增大(P均<0.05);且加入亲和素前(t=16.225,P<0.001)、后2种造影剂间粒径差异均有统计学意义(t=-5.046,P<0.001)。稳定性观察期间PFOB脂质微粒内浓度无明显改变,而C3F8脂质微泡随放置时间延长浓度呈减低趋势。加入亲和素后,PFOB脂质纳米粒回声明显增强;C3F8脂质微泡加入亲和素前后显影效果均较好。低声压(MI=0.28)及高声压(MI=0.56)环境下,PFOB脂质纳米粒造影剂显影强度无明显改变,而C3F8脂质微泡显影强度随辐照时间延长呈减低趋势。结论相较于C3F8脂质微泡,PFOB纳米脂质纳米粒造影剂粒径小、耐声压性好,更符合靶向超声造影剂的要求。

Objective To analyze contrast imaging characteristic and resistance to acoustic pressure of perfluorooctylbromide(PFOB) lipidic microbubbles and compared with perfluoropropane(C3F8) lipidic microbubbles in vitro. Methods PFOB lipidic particles with biotin and C3F8 lipidic microbubbles with biotin were prepared, and the stability of them were evaluated. Then the agents were used for imaging before and after adding of avidin, and the signal intensity were compared. Both PFOB particles and C3F8 microbubbles were exposed in ultrasound field of low(MI=0.28) and high(MI=0.56) ultrasound pressure levels. Their signal intensity after different exposure time(10, 20, 30 s) were compared. Results Aggregation occurred in both two contrast agents after addition of avidin,and the particle sizes were significantly larger before(both P<0.05). The differences of particle size between the two contrast agents were significant before(t=16.225, P<0.001) and after addition of avidin(t=-5.046,P<0.001). The concentration of PFOB lipid particles did not change significantly during the observation period of stability evaluation, while C3F8 microbubbles decreased with standing time. Addition of avidin produced significant imaging enhancement in PFOB particles. However, C3F8 microbubbles manifested ultrasonic backscatter before and after adding of avidin. The signal intensity of PFOB particles were stable under low(MI=0.28) and high acoustic pressure(MI=0.56). The signal intensity of C3F8 microbubbles decreased with the prolongation of exposure time under low(MI=0.28) and high acoustic pressure(MI=0.56). Conclusion Compared with C3F8microbubbles, PFOB particles with smaller particle size and better resistance to acoustic pressure, more suitable for targeted contrast ultrasound imaging.