In vitro biomedical applications of functionalized iron oxide nanoparticles, including those not related to magnetic properties

Abstract

Superparamagnetic iron oxide nanoparticles (SPION) are very promising contrast media, especially for molecular imaging, due to their superior NMR efficacy. They even have wider biomedical applications such as in drug and gene delivery, tissue engineering and bioseparation, or as sensitive biological nanosensors. By coupling them to affinity ligands, SPION can bind to drugs, proteins, enzymes, antibodies or nucleotides. For in vitro biomedical applications, the detection of molecular interaction is possible by using a diversity of systems capable of sensing the magnetic properties of these materials. The goal of the present work was to develop and validate various in vitro biomedical applications of ultrasmall superparamagnetic particles of iron oxide (USPIO), including some that are not related to their magnetic properties. USPIO coated with dextran, starch or bisphosphonate exposing carboxylate groups were synthesized and some of them were functionalized by conjugating various biomolecules, such as biotin, streptavidin and apoptosis, or VCAM-1 specific peptides. The in vitro biomedical applications assessed in the present work included: (1) the relaxometric measurement of antibody concentration, cell receptor expression, molecular interaction, and enzymatic activity in aqueous suspensions; (2) MRI visualization of cells and detection of molecular interaction in an ELISA system; (3) ELISA applications of USPIO derivatives; and (4) detection of specific biomolecules by histochemistry. Our results confirm that rapid and simple in vitro detection of a diversity of functionalized SPION with relevance in medicine is possible by the existing NMR techniques and by chemical staining reactions. The protocols can be applied to minimally prepared biological samples (e.g. whole blood, blood plasma or serum, cell suspensions, biopsies, histological preparations, etc.), and often do not need complicated systems of signal amplification. The use of SPION labeled compounds could furthermore contribute to cost reductions in the diagnosis and in patient care.

Development of a Magnetic Resonance Imaging Protocol for the Characterization of Atherosclerotic Plaque by Using Vascular Cell Adhesion Molecule-1 and Apoptosis-Targeted Ultrasmall Superparamagnetic Iron Oxide Derivatives

“…Labconsult, Brussels, Belgium), and Vectastain ABC kit (Vector Labconsult), as previously described 20 (Methods in the online-only Data Supplement).…”

Molecular Magnetic Resonance Imaging for the Detection of Vulnerable Plaques

“…OxLDL-targeted USPIO accumulation in atherosclerotic lesions is shown in D. A is modified with permission from Lipinski et al In vivo MRI after injection of monocrystalline iron oxides (cross-linked iron oxide) with VCAM-1 targeting peptides showed hypointense (dark) spots in the aortic root of apoE −/− mice, which was confirmed through fluorescence imaging ex vivo and in vitro in macrophages that overexpressed VCAM-1. 35,36 Burtea et al 37,38 recently developed much smaller Gd-DOTA as well as ultra small particle of iron oxide-based VCAM-1-targeted compounds. Both compounds have shown potential to image atherosclerotic plaques in hypercholesterolemic ApoE −/− mice.…”

“…Burtea et al 37,38 recently developed much smaller Gd-DOTA as well as ultra small particle of iron oxide-based VCAM-1-targeted compounds. Both compounds have shown potential to image atherosclerotic plaques in hypercholesterolemic ApoE −/− mice.…”

Determining the fate of seeded cells in venous tissue‐engineered vascular grafts using serial MRI

“…While intravital microscopy has recently been used to noninvasively monitor the development of TEVGs through the tracking of fluorescently labeled cells, it is not ideal because of the significant limitation of only being able to image superficial tissue and the inability to penetrate polymer‐based constructs used in our tissue engineering model (13). Cellular magnetic resonance imaging (MRI) has been the chosen imaging modality for obtaining deeper insight into the underlying in vivo biology of many systems and cellular processes without disturbing the native system dynamics because of its ability to depict tissues with greater spatial resolution than other clinical imaging modalities (14, 15), the capacity for whole‐body imaging without ionizing radiation (16–20), and the ability for near‐cellular resolution with the aid of targeted contrast agents (21, 22). The most widely used contrast agents for cellular MRI in tissue‐engineering applications are dextran‐coated superparamagnetic iron oxide nanoparticles (SPIOs).…”