Constantinidis Ioannis, Grant Samuel C, Simpson Nicholas E, Oca-Cossio Jose A, Sweeney Carol A, Mao Hui, Blackband Stephen J, Sambanis Athanassios
Department of Medicine, Division of Endocrinology, University of Florida College of Medicine, Gainesville, Florida 32610-0226, USA.
Magn Reson Med. 2009 Feb;61(2):282-90. doi: 10.1002/mrm.21833.
Noninvasive monitoring of tissue-engineered constructs is an important component in optimizing construct design and assessing therapeutic efficacy. In recent years, cellular and molecular imaging initiatives have spurred the use of iron oxide-based contrast agents in the field of NMR imaging. Although their use in medical research has been widespread, their application in tissue engineering has been limited. In this study, the utility of monocrystalline iron oxide nanoparticles (MIONs) as an NMR contrast agent was evaluated for betaTC-tet cells encapsulated within alginate/poly-L-lysine/alginate (APA) microbeads. The constructs were labeled with MIONs in two different ways: 1) MION-labeled betaTC-tet cells were encapsulated in APA beads (i.e., intracellular compartment), and 2) MION particles were suspended in the alginate solution prior to encapsulation so that the alginate matrix was labeled with MIONs instead of the cells (i.e., extracellular compartment). The data show that although the location of cells can be identified within APA beads, cell growth or rearrangement within these constructs cannot be effectively monitored, regardless of the location of MION compartmentalization. The advantages and disadvantages of these techniques and their potential use in tissue engineering are discussed.
组织工程构建体的无创监测是优化构建体设计和评估治疗效果的重要组成部分。近年来，细胞和分子成像计划推动了基于氧化铁的造影剂在核磁共振成像领域的应用。尽管它们在医学研究中的应用已经很广泛，但在组织工程中的应用却很有限。在本研究中，评估了单晶氧化铁纳米颗粒（MIONs）作为核磁共振造影剂对包裹在藻酸盐/聚-L-赖氨酸/藻酸盐（APA）微珠中的betaTC-tet细胞的效用。构建体用MIONs以两种不同方式进行标记：1）用MION标记的betaTC-tet细胞被包裹在APA微珠中（即细胞内区室），以及2）MION颗粒在包裹前悬浮于藻酸盐溶液中，以便藻酸盐基质被MIONs标记而非细胞（即细胞外区室）。数据表明，尽管可以在APA微珠内识别细胞位置，但无论MION分隔的位置如何，这些构建体内的细胞生长或重排都无法得到有效监测。讨论了这些技术的优缺点及其在组织工程中的潜在用途。
