Comparison of Superparamagnetic and Ultrasmall Superparamagnetic Iron Oxide Cell Labeling for Tracking Green Fluorescent Protein Gene Marker with Negative and Positive Contrast Magnetic Resonance Imaging

Abstract

The objectives of this study were to investigate the feasibility of imaging green fluorescent protein (GFP)-expressing cells labeled with iron oxide nanoparticles with the fast low-angle positive contrast steady-state free precession (FLAPS) method and to compare them with the traditional negative contrast technique. The GFP-R3230Ac cell line (GFP cell) was incubated for 24 hours using 20 microg Fe/mL concentration of superparamagnetic iron oxide (SPIO) and ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. Cell samples were prepared for iron content analysis and cell function evaluation. The labeled cells were imaged using positive contrast with FLAPS imaging, and FLAPS images were compared with negative contrast T2*-weighted images. The results demonstrated that SPIO and USPIO labeling of GFP cells had no effect on cell function or GFP expression. Labeled cells were successfully imaged with both positive and negative contrast magnetic resonance imaging (MRI). The labeled cells were observed as a narrow band of signal enhancement surrounding signal voids in FLAPS images and were visible as signal voids in T2*-weighted images. Positive contrast and negative contrast imaging were both valuable for visualizing labeled GFP cells. MRI of labeled cells with GFP expression holds potential promise for monitoring the temporal and spatial migration of gene markers and cells, thereby enhancing the understanding of cell- and gene-based therapeutic strategies.

Biomarkers in preclinical cancer imaging

“…Examples include: radiotracers, fluorescent molecules, paramagnetic ions or combinations thereof [9–18]. Small particles, including nanoparticles, liposomes and microbubbles, that can be (non)covalently bound to targeting molecules have also been developed [17, 19–23]. Such vectors are promising in the area of drug delivery and MRI, optical and photoacoustic imaging, contrast-enhanced ultrasonography and ultrasound molecular imaging, and thermoablative therapy [17, 19, 23–25].…”

Magnetic resonance imaging of glioma with novel APTS-coated superparamagnetic iron oxide nanoparticles

“…The molecular imaging (MI) of tumors has recently gained widespread use [1-4] due to its ability to facilitate quantitative and repetitive imaging of targeted molecules and biological processes in living organisms [2,5,6]. Contrast agents are generally required for high-quality MI diagnosis.…”

The conformational polymorphism of the green fluorescent protein

“…The green fluorescent protein (GFPuv) is excep tionally widely utilized in cell biology as a natural, brightly fluorescent marker for gene expression, local ization of gene products and intracellular protein to protein interactions [4][5][6][7][8]. In order to understand the complex photo physics of GFPuv, a considerable number of studies has been published [9][10][11][12].…”

“…Native PAGE analysis of purified GST GFPuv, GST and GFPuv (lanes[1][2][3][4][5][6][7][8][9][10][11][12]. To separate the native proteins we used 5% stacking gel and 12% separating gel.…”