温敏型液态氟碳纳米粒声致相变及体外超声显像

Heat-sensitive liquid perfluorocarbons nanoparticles for acoustic vaporation and in vitro ultrasound imaging

目的制备一种脂质包裹液态氟碳(PFP)的新型温敏型纳米粒(HSNP),观察其于加热和低强度聚焦超声(LIFU)辐照下的相变情况,体外检测其超声显影效果。方法采用薄膜分散法制备包裹PFP的HSNP。检测其物理性质;光镜下观察HSNP加热下的相变情况;制备内含HSNP高分子聚丙烯酰胺凝胶模型,同时建立含磷酸盐缓冲液(PBS)和脂质悬液的凝胶模型作为对照,观察LIFU辐照后凝胶模型的超声显影效果。结果成功制备包裹PFP的HSNP,其外观呈乳白色混悬液,镜下微球大小均一,形态规则,平均粒径(507.9±101.7)nm,平均电位(-5.87±4.41)mV。HSNP于45℃时开始转变为微气泡,随温度升高气泡随之增多增大。LIFU辐照前,基波和谐波下含PBS和脂质悬液凝胶模型呈无回声,含HSNP凝胶模型基波和谐波呈无回声为主伴散在点状高回声,LIFU辐照后,含PBS和脂质悬液凝胶模型基波下呈散在点状高回声,谐波下未见明显改变,含HSNP凝胶模型基波下呈密集点状强回声,谐波下呈细密点线状高回声;辐照后含HSNP凝胶模型平均超声灰度值(161.13±2.74)明显高于含PBS(24.09±2.38)和脂质悬液(25.03±2.50)凝胶模型(P均<0.05)。结论本研究制备包裹PFP的HSNP为新型超声造影剂,可声致相变,体外可实现增强超声显影。

Objective To prepate a new heat-sensitive nanoparticle（HSNP）packing perfluoropentane（PFP）,and to observe the phase-shift of HSNP under heating or low intensity focused ultrasound（LIFU）,and to explore ultrasound imaging of HSNP in vitro.Methods HSNP packing PFP was fabricated using thin-film dispersion method,and the basic physical characteristics were obtained.The phase-shift of HSNP under heating was observed by the light microscope.A HSNP-dispersed polyacrylamide hydrogel phantom was prepared and sonicated by LIFU to observe the ultrasound imaging effect.Phosphate buffered saline（PBS）-and lipid suspension-dispersed polyacrylamide hydrogel phantom were prepared as control.Results HSNP packing PFP was successfully prepared with milky suspension in appearence,homogeneous and regular morphology in microscope,diameter of（507.90±101.70）nm and potential of（-5.87±4.41）mV.Under 45℃,HSNP began to transform to microbubble,which increased and expanded along with the temperature.Before LIFU irradiation,PBS-and lipid suspension-dispersed hydrogel showed echoless,HSNP-dispersed hydrogel mainly showed echoless with scattered hyperecho under fundamental and harmonic wave.After LIFU irradiation,PBS-and lipid suspension-dispersed hydrogel showed scattered hyperecho under fundamental wave and echoless under harmonic wave,and HSNP-dispersed hydrogel showed intensive spot-hyperecho under fundamental wave and linear-hyperecho under harmonic wave.The grey level of ultrasonic intensity of HSNP-dispersed hydrogel（161.13±2.74）was significanly higher than that of PBS-dispersed hydrogel（24.09±2.38）and lipid suspension-dispersed hydrogel（25.03±2.50）.Conclusion The prepared HSNP packing PFP can be used as a novel contrast agent for acoustic vaporation and enhancing ultrasound imaging in vitro.