Browsing by Subject "Superparamagnetism"

Now showing 1 - 3 of 3

Open Access
Amphiphilic peptide coated superparamagnetic iron oxide nanoparticles for in vivo MR tumor imaging
(Royal Society of Chemistry, 2016) Ozdemir, A.; Ekiz, M. S.; Dilli, A.; Güler, Mustafa O.; Tekinay, A. B.
Magnetic resonance imaging (MRI) is a noninvasive imaging technique that provides high spatial resolution and depth with pronounced soft-tissue contrast for in vivo imaging. A broad variety of strategies have been employed to enhance the diagnostic value of MRI and detect tissue abnormalities at an earlier stage. Superparamagnetic iron oxide nanoparticles (SPIONs) are considered to be suitable candidates for effective imaging due to their small size, versatile functionality and better biocompatibility. Here, we demonstrate that coating SPIONs with proline-rich amphiphilic peptide molecules through noncovalent interactions leads to a water-dispersed hybrid system suitable as an MRI contrast agent. Cellular viability and uptake of amphiphilic peptide coated SPIONs (SPION/K-PA) were evaluated with human vascular endothelial cells (HUVEC) and estrogen receptor (ER) positive human breast adenocarcinoma (MCF-7) cells. The efficiency of SPION/K-PA as MRI contrast agents was analyzed in Sprague-Dawley rats with mammary gland tumors. MR imaging showed that SPION/K-PA effectively accumulated in tumor tissues, enhancing their imaging potential. Although nanoparticles were observed in reticuloendothelial system organs (RES) and especially in the liver and kidney immediately after administration, the MR signal intensity in these organs diminished after 1 h and nanoparticles were subsequently cleared from these organs within two weeks. Histological observations also validated the accumulation of nanoparticles in tumor tissue at 4 h and their bioelimination from the organs of both healthy and tumor-bearing rats after two weeks.
Open Access
Heating of magnetic fluid systems driven by circularly polarized magnetic field
(Elsevier BV * North-Holland, 2010) Ahsen, O. O.; Yilmaz, U.; Aksoy, M. Deniz; Ertas, G.; Atalar, Ergin
A theory is presented to calculate the heat dissipation of a magnetic suspension, a ferrofluid, driven by circularly polarized magnetic field. Theory is tested by in vitro experiments and it is shown that, regardless of the character of the relaxation process, linearly and circularly polarized magnetic field excitations, having the same root-mean-square magnitude, are equivalent in terms of heating efficiency.
Open Access
Peptide functionalized superparamagnetic iron oxide nanoparticles as MRI contrast agents
(The Royal Society of Chemistry, 2011) Sulek, S.; Mammadov, B.; Mahcicek, D. I.; Sozeri, H.; Atalar, Ergin; Tekinay, A. B.; Güler, Mustafa O.
Magnetic resonance imaging (MRI) attracts great attention in cellular and molecular imaging due to its non-invasive and multidimensional tomographic capabilities. Development of new contrast agents is necessary to enhance the MRI signal in tissues of interest. Superparamagnetic iron oxide nanoparticles (SPIONs) are used as contrast agents for signal enhancement as they have revealed extraordinary magnetic properties at the nanometre size and their toxicity level is very low compared to other commercial contrast agents. In this study, we developed a new method to functionalize the surface of SPIONs. Peptide amphiphile molecules are used to coat SPIONs non-covalently to provide water solubility and to enhance biocompatibility. Superparamagnetic properties of the peptide-SPION complexes and their ability as contrast agents are demonstrated. In vitro cell culture experiments reveal that the peptide-SPION complexes are biocompatible and are localized around the cells due to their peptide coating.