The morphology of particles, along with other particle attributes, has been shown to affect the biological fate of particles administered into the body. Particles with collapsed surfaces or shells (dimpled, buckled or crumpled) can have different appearances, under the microscope, that resemble many things encountered in our daily life, such as apples/cherries, doughnuts, and bowls. Recent studies have demonstrated that they are not just particles with interesting geometries, but they can also be used as functional blocks for assembled complex materials. Since previous research focus has been on micron-sized particles and organic solvents were often used, it is of particular interest to synthesize the nanosized counterpart with a buckled surface using a purely aqueous method. Herein we report a facile method for rapid synthesis of buckled silica nanoparticles (SiNPs) based on S-nitrosothiol chemistry in a solvent-free reaction. 3-Mercaptopropyl trimethoxysilane (MPTMS) was used as a single silane source in a one-pot aqueous solution containing sodium nitrite and polyvinyl alcohol (PVA). Upon the addition of HCl, S-nitrosation and condensation of MPTMS occur simultaneously and the reaction system undergoes a rapid transition from a clear solution to a solution containing nanoparticles with a lag time controlled mainly by the amount of HCl added. The experimental parameters were systematically studied to determine the optimal concentration of each component. For a typical reaction, sub-100 nm nanoparticles can be produced in less than 1 h, and the best result can be obtained within 2 to 4 h. Remarkably, the nanoparticle exhibits buckled surface morphologies under TEM and SEM. The average size is about 60 nm in diameter. Moreover, the solid-state Si-NMR data show that T² and T³ silicon species are rapidly evolved with slight dynamic changes over the reaction time. Further, PVA is shown to control the surface buckling as well as to stabilize the formed particles. The as-prepared SiNPs can be used as a nitric oxide (NO) carrier with the potential to release NO in an apparent zero-order manner. In conclusion, the study demonstrates the feasibility of employing an aqueous route for efficiently preparing SiNPs with multifarious surface cavities based on S-nitrosothiol chemistry.

中文翻译：

---

从硅烷单体到各向异性屈曲二氧化硅纳米球：聚合物介导，无溶剂和一锅合成

颗粒的形态以及其他颗粒属性已显示出会影响施用到体内的颗粒的生物命运。在显微镜下，具有塌陷表面或外壳（凹陷，弯曲或弄皱）的颗粒可能具有不同的外观，类似于我们日常生活中遇到的许多事物，例如苹果/樱桃，甜甜圈和碗。最近的研究表明，它们不仅是具有令人感兴趣的几何形状的粒子，而且还可以用作组装复杂材料的功能块。由于先前的研究重点是微米级颗粒，并且经常使用有机溶剂，因此特别感兴趣的是使用纯水性方法合成具有弯曲表面的纳米级对应物。S-亚硝基硫醇化学反应，无溶剂。3-巯基丙基三甲氧基硅烷（MPTMS）在包含亚硝酸钠和聚乙烯醇（PVA）的一锅水溶液中用作单一硅烷源。加入HCl后，SMPTMS的亚硝化和缩合同时发生，反应系统经历了从澄清溶液到含纳米颗粒溶液的快速转变，其滞后时间主要受HCl的加入量控制。系统研究了实验参数，以确定每种组分的最佳浓度。对于典型的反应，可以在不到1小时的时间内生产出100 nm以下的纳米颗粒，并且可以在2-4小时内获得最佳结果。值得注意的是，纳米颗粒在TEM和SEM下显示出弯曲的表面形态。平均尺寸为直径约60nm。此外，固态Si-NMR数据表明T ²和T ³随着反应时间的推移，硅物种迅速演化，并伴有轻微的动态变化。此外，显示出PVA可控制表面屈曲并稳定所形成的颗粒。所制备的SiNP可用作一氧化氮（NO）载体，具有以明显的零级方式释放NO的潜力。总而言之，该研究证明了基于S-亚硝基硫醇化学方法，采用水性途径有效制备具有多种表面空腔的SiNP的可行性。