PLGA微球在显像和治疗方面的多重应用

Multiple applications of PLGA nanoparticles in imaging and treatment of disease

超声造影以及其他影像增强技术已经成为临床诊断疾病的一个重要手段。然而与X线或核磁共振共振增强相比,超声造影的敏感性和特异性有待提高。聚乳酸-羟基乙酸共聚物(PLGA)作为生物相容性和降解性最好的材料之一,能制备成包裹各种药物和其他物质的纳米级或微米级微球超声造影剂,表面通过亲水性修饰和联接靶向配体,能顺利穿过肿瘤血管内皮间隙到达病灶边缘和内部,同时通过与其他技术如核磁共振、荧光、放疗、光声成像等的结合,能更准确地对病灶进行显影和治疗,有效的减少甚至避免了副作用。当前的应用不再局限于单一成像,而是同时联合两种或更多种成像技术进行优势互补。一方面,通过超声造影与核磁共振增强或荧光显影的结合,能更准确更清晰的显示病灶;另一方面通过高频聚焦超声治疗与核磁共振增强、放疗等技术的结合,使治疗的效果有了很大程度的提高。

Ultrasound and other imaging contrast angiography have become important means in diagnosing clinical diseases . However , compared with X-ray or magnetic resonance imaging , ultrasound contrast angiography still needs to improve its diagno-sing sensitivity and specificity .Through constant innovation , ultrasound contrast angiography agents have been developed tremen-dously.As one of the best materials in terms of biocompatibility and biodegradability , PLGA can be shaped into micro-or nano-particle ultrasound contrast angiography agent , which can encapsulate drugs , siRNA or other substances .Through hydrophilic modification on the surface of the agent and by linking the targeting ligand , the agent can penetrate through vascular endothelial gap smoothly and arrive at the tumor lesion edge and inside the tumor .Couple with other technologies such as magnetic resonance imaging, fluorography, radiotherapy and photo-acoustic imaging, ultrasound contrast angiography ensures more accurate and prompt diagnosis and treatment and effectively reduces side effects .Currently, the agent is no longer used alone in diagnosis . Rather, the agent is applied in combination with one or two other complementary diagnosing techniques .For one thing, ultrasonic contrast agent can be combined with magnetic resonance or fluorography , making the image of lesions more accurate and clearer;For the other , ultrasonic contrast agent can be combined with technologies such as high-intensity focused ultrasound therapy , mag-netic resonance imaging and radiotherapy , which significantly improves treatment effects .