C. Gansau

Magnetic Resonance of a Dextran-Coated Magnetic Fluid Intravenously Administered in Mice

Magnetic resonance was used to investigate the kinetic disposition of magnetite nanoparticles (9.4 nm core diameter) from the blood circulation after intravenous injection of magnetite-based dextran-coated magnetic fluid in female Swiss mice. In the first 60 min the time-decay of the nanoparticle concentration in the blood circulation follows the one-exponential (one-compartment) model with a half-life of (6.9 +/- 0.7) min. The X-band spectra show a broad single line at g approximately 2, typical of nanomagnetic particles suspended in a nonmagnetic matrix. The resonance field shifts toward higher values as the particle concentration reduces, following two distinct regimes. At the higher concentration regime (above 10(14) cm(-3)) the particle-particle interaction responds for the nonlinear behavior, while at the lower concentration regime (below 10(14) cm(-3)) the particle-particle interaction is ruled out and the system recovers the linearity due to the demagnetizing field effect alone.

Light microscopy and magnetic resonance characterization of a DMSA-coated magnetic fluid in mice

Light microscopy and magnetic resonance were used to investigate the biodistribution of magnetite nanoparticles coated with dimercaptosuccinic acid, after intravenous injection of a single dose in mice. Morphological analysis showed a huge amount of magnetic nanoparticles (MNPs) in the lung 30 min after injection. In contrast to the lung, morphological analysis revealed lower concentration of MNPs in the liver. A progressive decrease of MNPs in both lung and liver was observed from 30 min to 4 hours after intravenous injection. MNPs were not observed in any other organs using morphological analysis. In support of the LM observations MR signals were detected in both lung and liver as early as 5 min after injection. In addition, no MR signal was observed in the blood stream as early as 5 min after injection of the single dose.

Determination of binding constant Kb of biocompatible, ferrite-based magnetic fluids to serum albumin

In this work, we investigated the interaction between molecular-coated magnetic nanoparticles (MC-MNPs) and serum albumin proteins (BSA) through the fluorescence quenching of the tryptophan residue present in BSA after the binding of MC-MNPs to specific sites. Three different biocompatible magnetic fluid (BMF) samples based on magnetite or cobalt–ferrite MNPs coated with citric acid or dextran were used. The binding constant and the stoichiometry of the investigated MNPs indicate that the BMF based on cobalt–ferrite is more site specific and more strongly bound to the BSA than the BMFs based on magnetite. The results may direct the design of new magnetic drug-carriers based on BMFs.In this work, we investigated the interaction between molecular-coated magnetic nanoparticles (MC-MNPs) and serum albumin proteins (BSA) through the fluorescence quenching of the tryptophan residue present in BSA after the binding of MC-MNPs to specific sites. Three different biocompatible magnetic fluid (BMF) samples based on magnetite or cobalt–ferrite MNPs coated with citric acid or dextran were used. The binding constant and the stoichiometry of the investigated MNPs indicate that the BMF based on cobalt–ferrite is more site specific and more strongly bound to the BSA than the BMFs based on magnetite. The results may direct the design of new magnetic drug-carriers based on BMFs.

Magnetic resonance and light microscopy investigation of a dextran coated magnetic fluid

A dextran-coated magnetite-based magnetic fluid (MF) sample (DexMF) was developed for cancer diagnostic and therapeutic purposes. In order to perform biological studies DexMF samples were endovenously injected into female Swiss mice. Magnetic resonance (MR) spectra showed a broad line around g=2, typical of magnetic nanoparticles (MNPs) suspended in a nonmagnetic matrix. The MR data showed that MNPs essentially spread in liver, spleen, and bone marrow. MNPs in blood stream were found up to 60 min after injection. Histological analysis also showed MNP agglomeration in liver, spleen, and bone marrow, from 1 h up to 28 days. No damaged cells or any other kind of alteration were observed in the investigated tissues. The data suggested that DexMF sample is biocompatible and adequate for biomedical applications.

Photoacoustic spectroscopy: a promising technique to investigate magnetic fluids

In the present study, we investigate biocompatible magnetic fluids (BMFs) by photoacoustic spectroscopy and the investigation are based on magnetic nanoparticles surface-coated with citric acid and dispersed in physiological media (pH8 and 0.9 salinity).

Magnetic resonance study of zero-field-frozen magnetite-based biocompatible magnetic fluid

In this paper, a biocompatible MF sample was investigated using X-band MR. The resonance linewidth broadening (/spl Delta/H/sub R/) and the resonance field (H/sub R/) was investigated as a function of temperature (T), at different nonparticle concentration. The biocompatible MF sample used in this study is based on magnetic nanoparticle (9.4 nm is average diameter) coated with dextran. After precipitation in alkaline medium, magnetite nanoparticles were surface coated to produce stable biocompatible MF samples at physiological pH and salinity.

Biocompatible magnetic fluids: a comparative birefringence investigation

Abstract The static magnetic birefringence (SMB) of magnetite-based magnetic fluids coated with dextran and dimercaptosuccinic acid was investigated using the recent model proposed by Skeff Neto et al. (J. Appl. Phys. 89 (2001) 3362). The SMB data of samples presenting particle concentration around 1.2×10 16 particle/cm 3 were successfully described. The particle size distribution obtained from the fit of the SMB data was discussed in comparison with the data obtained from transmission electron microscopy.

Uptake of DMSA-coated magnetic nanoparticles by blood cells

In this paper, we investigated blood cells participation in the transfer of DMSA-coated MNPs from blood vessels to the lung parenchyma.

In vivo investigation of DMSA-coated magnetic fluid

Summary form only given. Magnetic fluids (MFs) have been used as a promising technological basis for biomedical applications. In the present study a biocompatible magnetic fluid (BMF) sample is given as an intravenous bolus dose to mice. Magnetic resonance (MR) and light microscopy (LM) are used to investigate the biodistribution of the nanomagnetic-based material over several organs and the time-decay of the BMF sample in the blood circulation, up to four hours after injection. The BMF sample used in this study contains magnetite nanoparticles surface-coated with DMSA to obtain a stable sample at physiological pH and salinity.