Thapa Bibek, Diaz-Diestra Daysi, Beltran-Huarac Juan, Weiner Brad R, Morell Gerardo
Department of Physics, University of Puerto Rico, San Juan, PR, 00931, USA.
Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR, 00926, USA.
Nanoscale Res Lett. 2017 Dec;12(1):312. doi: 10.1186/s11671-017-2084-y. Epub 2017 Apr 27.
Superparamagnetic iron oxide nanoparticles (SPIONs, ~11-nm cores) were PEGylated without anchoring groups and studied as efficient MRI T contrast agents (CAs). The ether group of PEG is efficiently and directly linked to the positively charged surface of SPIONs, and mediated through a dipole-cation covalent interaction. Anchor-free PEG-SPIONs exhibit a spin-spin relaxivity of 123 ± 6 mMs, which is higher than those of PEG-SPIONs anchored with intermediate biomolecules, iron oxide nanoworms, or Feridex. They do not induce a toxic response for Fe concentrations below 2.5 mM, as tested on four different cell lines with and without an external magnetic field. Magnetic resonance phantom imaging studies show that anchor-free PEG-SPIONs produce a significant contrast in the range of 0.1-0.4 [Fe] mM. Our findings reveal that the PEG molecules attached to the cores immobilize water molecules in large regions of ~85 nm, which would lead to blood half-life of a few tens of minutes. This piece of research represents a step forward in the development of next-generation CAs for nascent-stage cancer detection. Contrast-probed anchor-free PEGylated iron oxide contrast agent.
超顺磁性氧化铁纳米颗粒（SPIONs，核心尺寸约11纳米）在未连接锚定基团的情况下进行了聚乙二醇化修饰，并作为高效的磁共振成像T2对比剂（CAs）进行了研究。聚乙二醇的醚基与SPIONs带正电的表面高效且直接相连，并通过偶极-阳离子共价相互作用介导。无锚定基团的聚乙二醇化超顺磁性氧化铁纳米颗粒的自旋-自旋弛豫率为123±6 mM-1s-1，高于通过中间生物分子、氧化铁纳米蠕虫或菲立磁（Feridex）锚定的聚乙二醇化超顺磁性氧化铁纳米颗粒。在有和没有外部磁场的情况下，在四种不同细胞系上进行测试，结果表明，对于铁浓度低于2.5 mM的情况，它们不会诱导毒性反应。磁共振体模成像研究表明，无锚定基团的聚乙二醇化超顺磁性氧化铁纳米颗粒在0.1-0.4[Fe] mM范围内产生显著的对比效果。我们的研究结果表明，附着在核心上的聚乙二醇分子在约85纳米的大区域内固定水分子，这将导致数十分钟的血液半衰期。这项研究代表了用于早期癌症检测的下一代对比剂开发的一个进步。对比探测的无锚定基团聚乙二醇化氧化铁对比剂。
