Masotti A, Pitta A, Ortaggi G, Corti M, Innocenti C, Lascialfari A, Marinone M, Marzola P, Daducci A, Sbarbati A, Micotti E, Orsini F, Poletti G, Sangregorio C
Dipartimento di Chimica, SAPIENZA Università di Roma, P.le A.Moro 5, 00185 Rome, Italy.
MAGMA. 2009 Apr;22(2):77-87. doi: 10.1007/s10334-008-0147-x. Epub 2008 Oct 15.
Use of polyethylenimines (PEIs) of different molecular weight and selected carboxylated-PEI derivatives (PEI-COOH) in the synthesis and stabilization of iron oxide nanoparticles, to obtain possible multifunctional contrast agents.
Oxidation of Fe(II) at slightly elevated pH and temperature resulted in the formation of highly soluble and stable nanocomposites of iron oxides and polymer. Composites were characterized and studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffractometry, AC and DC magnetometry, NMR relaxometry and magnetic resonance imaging (MRI).
From AFM the dimensions of the aggregates were found to be in the ~150-250 nm size region; the mean diameter of the magnetic core of the compounds named PEI-25, PEI-500 and PEI-COOH60 resulted d approximately 20 +/- 5 nm for PEI-25, d approximately 9.5 +/- 1.0 nm for PEI-500 and d approximately 6.8 +/- 1.0 nm for PEI-COOH60. In PEI-COOH60 TEM and X-ray diffractometry revealed small assemblies of mineral magnetic cores with clear indications that the main constituents are maghemite and/or magnetite as confirmed by AC and DC SQUID magnetometry. For PEI-COOH60, the study of NMR-dispersion profiles revealed r (1) and r (2) relaxivities comparable to superparamagnetic iron-oxide commercial compounds in the whole investigated frequency range 7 < or = nu < or = 212 MHz.
PEI-25 was studied as possible MRI contrast agent (CA) to map the cerebral blood volume (CBV) and cerebral blood flow (CBF) in an animal model obtaining promising results. The reported compounds may be further functionalized to afford novel multifunctional systems for biomedical applications.
使用不同分子量的聚乙烯亚胺（PEIs）以及选定的羧化聚乙烯亚胺衍生物（PEI-COOH）来合成和稳定氧化铁纳米颗粒，以获得可能的多功能造影剂。
在略高的pH值和温度下氧化Fe(II)，导致形成高度可溶且稳定的氧化铁与聚合物纳米复合材料。通过原子力显微镜（AFM）、透射电子显微镜（TEM）、X射线衍射、交流和直流磁强计、核磁共振弛豫测量以及磁共振成像（MRI）对复合材料进行表征和研究。
通过AFM发现聚集体尺寸在约150 - 250 nm范围内；名为PEI-25、PEI-500和PEI-COOH60的化合物的磁芯平均直径，PEI-25约为20±5 nm，PEI-500约为9.5±1.0 nm，PEI-COOH60约为6.8±1.0 nm。在PEI-COOH60中，TEM和X射线衍射显示出矿物磁芯的小聚集体，交流和直流超导量子干涉装置磁强计证实其主要成分是磁赤铁矿和/或磁铁矿。对于PEI-COOH60，在整个研究频率范围7≤ν≤212 MHz内，核磁共振弥散曲线研究显示其r(1)和r(2)弛豫率与超顺磁性氧化铁商业化合物相当。
研究了PEI-25作为可能的磁共振成像造影剂（CA）在动物模型中绘制脑血容量（CBV）和脑血流量（CBF）的情况，获得了有前景的结果。所报道的化合物可进一步功能化，以提供用于生物医学应用的新型多功能系统。
