Kwiatkowski Grzegorz, von Witte Gevin, Däpp Alexander, Kocic Jovana, Hattendorf Bodo, Ernst Matthias, Kozerke Sebastian
Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
Laboratory of Inorganic Chemistry, ETH Zurich, Switzerland.
Magn Reson Med. 2024 Dec;92(6):2631-2640. doi: 10.1002/mrm.30244. Epub 2024 Aug 9.
The objective of the present work was to test the feasibility of in vivo imaging of hyperpolarized 50-nm silicon-29 (Si) nanoparticles.
Commercially available, crystalline 50-nm nanoparticles were hyperpolarized using dynamic polarization transfer via the endogenous silicon oxide-silicon defects without the addition of exogenous radicals. Phantom experiments were used to quantify the effect of sample dissolution and various surface coating on T and T relaxation. The in vivo feasibility of detecting hyperpolarized silicon-29 was tested following intraperitoneal, intragastric, or intratumoral injection in mice and compared with the results obtained with previously reported, large, micrometer-size particles. The tissue clearance of SiNPs was quantified in various organs using inductively coupled plasma optical emission spectroscopy.
In vivo images obtained after intragastric, intraperitoneal, and intratumoral injection compare favorably between small and large SiNPs. Improved distribution of small SiNPs was observed after intraperitoneal and intragastric injection as compared with micrometer-size SiNPs. Sufficient clearance of nanometer-size SiNPs using ex vivo tissue sample analysis was observed after 14 days following injection, indicating their safe use.
In vivo MRI of hyperpolarized small 50-nm SiNPs is feasible with polarization levels and room-temperature relaxation times comparable to large micrometer-size particles.
本研究的目的是测试超极化的50纳米硅-29（Si）纳米颗粒体内成像的可行性。
使用市售的50纳米晶体纳米颗粒，通过内源性氧化硅-硅缺陷进行动态极化转移实现超极化，无需添加外源自由基。通过体模实验量化样品溶解和各种表面涂层对T1和T2弛豫的影响。在小鼠腹腔内、胃内或瘤内注射后，测试检测超极化硅-29的体内可行性，并与先前报道的微米级大颗粒的结果进行比较。使用电感耦合等离子体发射光谱法对各种器官中SiNPs的组织清除情况进行量化。
胃内、腹腔内和瘤内注射后获得的体内图像显示，小尺寸和大尺寸SiNPs之间具有良好的对比。与微米级SiNPs相比，腹腔内和胃内注射后观察到小尺寸SiNPs的分布有所改善。注射后14天，通过离体组织样本分析观察到纳米级SiNPs有足够的清除，表明它们可以安全使用。
超极化的50纳米小尺寸SiNPs的体内MRI是可行的，其极化水平和室温弛豫时间与微米级大颗粒相当。
