生物谷Bioon.com 讯 把超声波与磁共振成像（MRI）磁场结合起来可能帮助科学家向大脑的特定区域供给携带药物的颗粒。Kuo-Chen Wei及其同事把涂敷了常见抗癌药物的磁性纳米颗粒导向了大鼠的癌性脑瘤。此前的研究已经证明了聚焦的超声波可以临时破坏局部血脑屏障（血脑屏障是通向大脑的毛细血管上的一系列保护性的“闸门”），让大分子治疗更多地进入中枢神经系统。
这组科学家在对大鼠注射携带药物的磁性颗粒之后对其大脑施加了超声波，并且辅以磁共振成像（MRI）的强力磁场和实时成像，把这些颗粒导向了肿瘤部位。测试显示，在把磁打靶和聚焦超声波方法结合起来而非单独使用其中任何一种的时候，更多的携带药物的颗粒聚集在了指定的脑部位，而且用联合疗法治疗的大鼠比未经治疗的大鼠存活时间长了66%。
目前静脉注射给药的大脑治疗需要大剂量以确保受影响的区域达到足够的浓度。这组作者说，该研究可能有助于科学家开发出对患者副作用更少的非侵入性治疗脑疾病的方法。（生物谷Bioon.com）
生物谷推荐原文出处：
PNAS doi: 10.1073/pnas.1003388107
Magnetic resonance monitoring of focused ultrasound/magnetic nanoparticle targeting delivery of therapeutic agents to the brain
Hao-Li Liu a,b,1, Mu-Yi Hua c,1, Hung-Wei Yang c,1, Chiung-Yin Huang d, Po-Chun Chu a, Jia-Shin Wu a, I-Chou Tseng d, Jiun-Jie Wang e, Tzu-Chen Yen b,f, Pin-Yuan Chen d,g,2,3, and Kuo-Chen Weid,2,3
Departments of aElectrical Engineering, cChemical and Material Engineering, and eMedical Image and Radiological Sciences and gGraduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan 333, Taiwan; bMolecular Imaging Center and fDepartment of Nuclear Medicine, Chang-Gung Memorial Hospital, Taoyuan 333, Taiwan; and dDepartment of Neurosurgery, Chang-Gung University College of Medicine and Memorial Hospital, Taoyuan 333, Taiwan
The superparamagnetic properties of magnetic nanoparticles (MNPs) allow them to be guided by an externally positioned magnet and also provide contrast for MRI. However, their therapeutic use in treating CNS pathologies in vivo is limited by insufficient local accumulation and retention resulting from their inability to traverse biological barriers. The combined use of focused ultrasound and magnetic targeting synergistically delivers therapeutic MNPs across the blood–brain barrier to enter the brain both passively and actively. Therapeutic MNPs were characterized and evaluated both in vitro and in vivo, and MRI was used to monitor and quantify their distribution in vivo. The technique could be used in normal brains or in those with tumors, and significantly increased the deposition of therapeutic MNPs in brains with intact or compromised blood–brain barriers. Synergistic targeting and image monitoring are powerful techniques for the delivery of macromolecular chemotherapeutic agents into the CNS under the guidance of MRI.
