Mechanically Tunable Hollow Silica Ultrathin Nanoshells for Ultrasound Contrast Agents.
Mechanically Tunable Hollow Silica Ultrathin Nanoshells for Ultrasound Contrast Agents.
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DOI：
10.1002/adfm.201500610
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发表时间：
2015-07-08
影响因子：
19
通讯作者：
Kummel AC
中科院分区：
文献类型：
--
作者：
Liberman A;Wang J;Lu N;Viveros RD;Allen CA;Mattrey RF;Blair SL;Trogler WC;Kim MJ;Kummel AC
全氟戊烷（PFP）气体填充的可生物降解的掺铁二氧化硅纳米壳已被证明是长寿命的超声造影剂。以正硅酸四甲酯（TMOS）和乙醇铁为原料，采用溶胶-凝胶法合成了纳米壳。用R-取代的三烷氧基硅烷取代一部分TMOS产生具有不同壳厚度和由熔融纳米片组成的形态的纳米壳。与仅用TMOS合成的对照纳米壳相比，TMOS纳米壳具有超过3小时的连续超声多普勒成像寿命，使用对比度特异性成像时亮度是其两倍，并且具有降低的压力阈值。透射电子显微镜（TEM）表明，R-基团取代的三烷氧基硅烷可以减少机械临界纳米壳层至1.4 nm。这些纳米壳具有弱连接纳米片的机械行为，但具有二氧化硅的化学稳定性。该合成可以适用于由纳米片组成的三维纳米结构的一般制造，其具有1.4-3.8 nm的厚度和2-23 nm的直径。
Perfluoropentane (PFP) gas filled biodegradable iron-doped silica nanoshells have been demonstrated as long-lived ultrasound contrast agents. Nanoshells are synthesized by a sol-gel process with tetramethyl orthosilicate (TMOS) and iron ethoxide. Substituting a fraction of the TMOS with R-substituted trialkoxysilanes produces ultrathin nanoshells with varying shell thicknesses and morphologies composed of fused nanoflakes. The ultrathin nanoshells had continuous ultrasound Doppler imaging lifetimes exceeding 3 hours, were twice as bright using contrast specific imaging, and had decreased pressure thresholds compared to control nanoshells synthesized with just TMOS. Transmission electron microscopy (TEM) showed that the R-group substituted trialkoxysilanes could reduce the mechanically critical nanoshell layer to 1.4 nm. These ultrathin nanoshells have the mechanical behavior of weakly linked nanoflakes but the chemical stability of silica. The synthesis can be adapted for general fabrication of three-dimensional nanostructures composed of nanoflakes, which have thicknesses from 1.4–3.8 nm and diameters from 2–23 nm.