Martinez de la Torre Celia, Freshwater Kasey A, Looney-Sanders Mara A, Wang Qiang, Bennewitz Margaret F
Department of Chemical and Biomedical Engineering, Benjamin M. Statler College of Engineering and Mineral Resources, West Virginia University, Morgantown, West Virginia 26506, United States.
Shared Research Facilities, West Virginia University, Morgantown, West Virginia 26506, United States.
ACS Omega. 2023 May 18;8(21):18799-18810. doi: 10.1021/acsomega.3c00892. eCollection 2023 May 30.
Nano-encapsulated manganese oxide (NEMO) particles are noteworthy contrast agents for magnetic resonance imaging (MRI) due to their bright, pH-switchable signal ("OFF" to "ON" at low pH), high metal loading, and targeting capability for increased specificity. For the first time, we performed a head-to-head comparison of NEMO particles from In-house and commercialized sources (US Nano vs Nanoshel) to assess their potential as bright T MRI contrast agents. Manganese oxide nanocrystals (MnO, MnO, and MnO) were systematically evaluated for size, chemistry, release of manganese ions, and MRI signal pre- and post-encapsulation within poly(lactic--glycolic acid) (PLGA). Suprisingly, a majority of the commercialized formulations were not as advertised by displaying unintended sizes, morphologies, chemistry, dissolution profiles, and/or MRI signal that precludes in vivo use. US Nano's MnO and MnO nanocrystals contained impurities that impacted Mn ion release as well as micron-sized rodlike structures. Nanoshel's MnO and MnO nanoparticles had very large hydrodynamic sizes (>600 nm). In-house MnO and Nanoshel's MnO nanoparticles demonstrated the best characteristics with brighter T MRI signals, small hydrodynamic sizes, and high encapsulation efficiencies. Our findings highlight that researchers must confirm the properties of purchased nanomaterials before utilizing them in desired applications, as their experimental success may be impacted.
纳米封装的氧化锰（NEMO）颗粒因其明亮的、可随pH值切换的信号（在低pH值下从“关闭”到“开启”）、高金属负载量以及增强特异性的靶向能力，是磁共振成像（MRI）值得关注的造影剂。我们首次对来自内部和商业化来源（美国纳米公司与纳米壳公司）的NEMO颗粒进行了直接比较，以评估它们作为明亮的T1 MRI造影剂的潜力。对氧化锰纳米晶体（MnO、MnO₂和MnO₃）在聚乳酸-乙醇酸共聚物（PLGA）中的尺寸、化学性质、锰离子释放以及封装前后的MRI信号进行了系统评估。令人惊讶的是，大多数商业化制剂并未如宣传的那样，存在意外的尺寸、形态、化学性质、溶解曲线和/或MRI信号，这排除了其体内使用的可能性。美国纳米公司的MnO和MnO₂纳米晶体含有影响锰离子释放的杂质以及微米级的棒状结构。纳米壳公司的MnO和MnO₃纳米颗粒具有非常大的流体动力学尺寸（>600 nm）。内部制备的MnO和纳米壳公司的MnO纳米颗粒表现出最佳特性，具有更明亮的T1 MRI信号、小的流体动力学尺寸和高封装效率。我们的研究结果强调，研究人员在将购买的纳米材料用于预期应用之前必须确认其性质，因为它们的实验成功可能会受到影响。
