气体微泡光声造影剂的靶向修饰与应用

气体微泡作为一种新型的光声造影剂,由于其具有生物相容性良好、成像灵敏度高、易于修饰等优点,在生物医学成像领域引起了广泛的关注。然而,气体微泡的非靶向性限制了其在临床上的应用。为了提高气体微泡的光声造影剂的靶向性和特异性,需要对其进行靶向修饰。本文综述气体微泡的光声造影剂的靶向修饰方法,包括物理修饰法、化学修饰法和生物修饰法,阐述气体微泡的光声造影剂的靶向修饰在肿瘤成像、炎症成像、感染成像和血管成像中的应用,分析气体微泡的光声造影剂的靶向修饰的优势和局限性,展望未来的发展方向。

惰性气体微泡联合低频低强度超声辐照对人胰腺癌PANC-1细胞抑癌作用的实验研究

目的探讨惰性气体微泡联合低频低强度超声连续辐照对人胰腺癌PANC-1细胞的抑癌作用。方法将对数生长且浓度为1×106/ml的人胰腺癌PANC-1单细胞悬液按不同处理方法分成4组:空白对照组(加入2.0 ml人胰腺癌PANC-1单细胞悬液)、惰性气体微泡组(加入1600μl人胰腺癌PANC-1单细胞悬液和400μl SonoVue混悬液并充分混匀)、低频低强度超声组(加入2.0 ml人胰腺癌PANC-1单细胞悬液,再用声强0.60 W/cm2、频率1 MHz的超声波连续辐照60 s)和微泡+超声组(加入1600μl人胰腺癌PANC-1单细胞悬液和400μl SonoVue混悬液并充分混匀,再用声强0.60 W/cm2、频率1 MHz的超声波连续辐照60 s)。检测并比较各组细胞增殖活性和细胞凋亡率。结果空白对照组、惰性气体微泡组、低频低强度超声组、微泡+超声组人胰腺癌PANC-1细胞增殖活性分别为0.9356±0.1652、1.1126±0.0738、0.3236±0.0126、0.1566±0.0137,微泡+超声组细胞增殖活性均低于其余各组,差异均有统计学意义(均P<0.05)。空白对照组、惰性气体微泡组、低频低强度超声组、微泡+超声组人胰腺癌PANC-1细胞凋亡率分别为0.069±0.007、0.033±0.006、0.279±0.016、0.678±0.018,微泡+超声组细胞凋亡率均高于其余各组,差异均有统计学意义(均P<0.05)。结论惰性气体微泡联合低频低强度超声连续辐照能降低体外培养的人胰腺癌PANC-1细胞增殖,诱导细胞凋亡,具有明显的抑癌作用,为肿瘤治疗提供新的研究思路。

模具型腔气体压力对微发泡注塑件表面质量的影响

微发泡注塑成型制品表面的螺旋纹及银纹缺陷阻碍了此新工艺的推广应用,此缺陷主要是由填充过程中熔体流动前沿的泡孔发生破裂造成的。为提高微发泡注塑件的表面质量,提出一种利用高压氮气进行加压并使用高压容器进行稳压的模具型腔气体压力控制方法,构建相应的模具型腔气体压力控制装置和控制系统,进行某种医疗器械外观产品的气体反压(Gas counter pressure,GCP)微发泡注塑试验,研究填充过程中模具型腔气体压力对微发泡注塑件表面质量的影响规律。结果表明,随着模具型腔气体压力的提高,微发泡注塑件表面螺旋纹及银纹逐渐减少直至消除,塑件表面光泽度显著提高,塑件表面粗糙度明显降低。对选用的ABS材料,模具型腔气体压力为3 MPa时可获得表面质量优良的微发泡注塑产品。

A system for evaluation of ultrasound contrast agent's enhancement effect

A system for in vitro investigation of ultrasound contrast agent＇s enhancement effect is presented and evaluated. It includes the digital B-mode ultrasound scanner Belson3000A, the tissue-mimicking ultrasound phantoms and the software which is used for image quantitative analysis. The linear range, optimal settings and repeatability of the system are assessed and explored by scanning the ultrasound phantoms with different reflective intensities. The measurements are performed under an acoustic power from 4.8 to 12.3 mW, the scanner centre frequency is 3.5 MH and the gain setting is 50 dB. Both a self-made surfactant encapsulated microbubble and a commercial ultrasound contrast agent are scanned. The results show that the pixel intensity of ultrasonic images increases with the increase in the sound power, and for the stronger reflective phantoms of more particles, the increasing trend is much more evident. The system is optimal for evaluating the microbubble contrast agents＇ enhancement effects. It presents a simple, effective and real-time means for characterizing the enhancement ability of microbubbles.

Hollow micro- and nano-particles by gas foaming

This paper presents the results of a first successful attempt to produce hollow micro- and nano-particles of a large variety of materials, dimensions, shapes and hollow attributes by using an environmentally friendly and cheap technology, common in polymer processing and known as gas foaming. The central role played by ad hoc polymeric hollow micro- and nano-particles in a variety of emerging applications such as drug delivery, medical imaging, advanced materials, as well as in fundamental studies in nanotechnology highlights the wide relevance of the proposed method. Our key contribution to overcome the physical lower bound in the micro- and nano-scale gas foaming was to embed, prior to foaming, bulk micro- and nano-particles in a removable and deformable barrier film, whose role is to prevent the loss of the blowing agent, which is otherwise too fast to allow bubble formation. Furthermore, the barrier film allows for non-isotropic deformation of the particle and/or of the hollow, affording non-spherical hollow particles. In comparison with available methods to produce hollow micro- and nano-particles, our method is versatile since it offers independent control over the dimensions, material and shape of the particles, and the number, shape and open/closed features of the hollows. We have gas- foamed polystyrene and poly-（lactic-co-glycolic） acid particles 200 ~m to 200 nm in size, spherical, ellipsoidal and discoidal in shape, obtaining open or closed, single or multiple, variable in size hollows.

Numerical investigation of turbulent bubbly wakes created by the ventilated partial cavity

This paper presents a numerical study on the turbulent bubbly wakes created by the ventilated partial cavity.A semi-empirical approach is introduced to model the discrete interface of the ventilated cavity and its complex gas leakage rate induced by the local turbulent shear stress.Based on the Eulerian-Eulerian two-fluid modeling framework,a population balance approach based on MUltiple-SIze-Group (MUSIG) model is incorporated to simulate the size evolution of the sheared off microbubbles and its complex interactions with the two-phase flow structure in the wake region.Numerical predictions at various axial locations downstream of the test body were in satisfactory agreement with the experimental measurements.The captured bubbly wake structure illustrates that the bubbles may disperse as a twin-vortex tube driven by gravity effect.The predicted Sauter mean bubble diameter has confirmed the dominance of the coleascense process in the axial direction.As the bubbles develop downstream,the coleascense and breakup rate gradually reach balance,resulting in the stable bubble diameter.A close examination of the flow structures,gas void fraction distributions and the bubble size evolution provides valuable insights into the complex physical phenomenon induced by ventilated cavity.