Casein-Coated Iron Oxide Nanoparticles for High MRI Contrast Enhancement and Efficient Cell Targeting

Abstract

Surface properties, as well as inherent physicochemical properties, of the engineered nanomaterials play important roles in their interactions with the biological systems, which eventually affect their efficiency in diagnostic and therapeutic applications. Here we report a new class MRI contrast agent based on milk casein protein coated iron oxide nanoparticles (CNIOs) with a core size of 15 nm and hydrodynamic diameter ~30 nm. These CNIOs exhibited excellent water-solubility, colloidal stability, and biocompatibility. Importantly, CNIOs exhibited prominent T2 enhancing capability with a transverse relaxivity r2 of 273 mM−1s−1 at 3 Tesla. The transverse relaxivity is ~2.5-fold higher than that of iron oxide nanoparticles with the same core but an amphiphilic polymer coating. CNIOs showed pH-responsive properties, formed loose and soluble aggregates near the pI (pH~4.0). The aggregates could be dissociated reversibly when the solution pH was adjusted away from the pI. The transverse relaxation property and MRI contrast enhancing effect of CNIOs remained unchanged in the pH range of 2.0 to 8.0. Further functionalization of CNIOs can be achieved via surface modification of the protein coating. Bio-affinitive ligands, such as a single chain fragment from the antibody of epidermal growth factor receptor (ScFvEGFR), could be readily conjugated onto the protein coating, enabling specific targeting to MDA-MB-231 breast cancer cells over-expressing EGFR. T2-weighted MRI of mice intravenously administered with CNIOs demonstrated strong contrast enhancement in the liver and spleen. These favorable properties suggest CNIOs as a class of biomarker targeted magnetic nanoparticles for MRI contrast enhancement and related biomedical applications.

Preparation of Lysine-Coated Magnetic Fe2O3Nanoparticles and Influence on Viability of A549 Lung Cancer Cells

“…The experimental treatment for lung cancer is developed quickly in China Liang et al, 2013;Wang et al, 2013;Zhang et al, 2013). Oxide magnetic nanoparticles were widely applied in biomedical domain, especially in MRI contrast agent.…”

Functionalized milk-protein-coated magnetic nanoparticles for MRI-monitored targeted therapy of pancreatic cancer

“…16 Herein, we report a new targeted drug delivery nanosystem based on milk protein (casein [CN])-coated magnetic iron oxide (CNIO) nanoparticles, composed of a cancer cell targeting moiety that is the amino-terminal fragment (ATF) of urokinase plasminogen activator with an affinity to urokinase plasminogen activator receptor (uPAR), and the anticancer agent or CDDP for pancreatic cancer treatment. CNIO nanoparticles is not only an excellent magnetic resonance imaging (MRI) probe as previously reported, 17,18 but is also capable of loading a sufficient amount of CDDP in the CN layer through the ligand exchange of chloride groups in CDDP with the carboxyl groups in the CN protein. 19 The coating layer also renders sustained CDDP release, allowing sustained drug concentrations during circulation as well as targeted delivery and reduction of side effects due to the rapid release to the normal organs.…”

“…17 Human ATF peptide of the receptor-binding domain of uPA was prepared according to the established protocol. 20 The ATF peptide was then conjugated to CNIO nanoparticles through EDC/NHS cross-link.…”

“…Pt concentration was measured by colorimetric method with o-phenylenediamine (OPDA), 21 while Fe concentration was determined by the phenanthroline colorimetric method. 17 The percentage of CDDP loaded on CNIO nanoparticles was …”

“…Prussian blue staining for the presence of iron was performed on tissues collected from the major organs and tumors following our established protocol. 17,22 Immunofluorescence labeling for uPAR was performed using a rabbit anti-uPAR monoclonal antibody, followed by Alexa Fluor 555 goat anti-rabbit IgG secondary antibody. Sirius red staining for collagen in stromal structures was performed following an established protocol.…”