Papers by Keyword: Magnetic Fluid Hyperthermia

Abstract: Magnetic nanoparticle heating in alternating magnetic field is the novel approach to the hyperthermia technique for cancer treatment. The accurate measuring of the specific heat absorption rate of the magnetic fluid is the critical issue in the search for efficient materials to minimize the concentration of the magnetic nanoparticles in human tissues. In this work the heat absorption measurement setup consisting of a system of the magnetic field generation, a temperature measuring system, a cooling system, and an external computer control system has been developed. The results of the calibration as well as the results of measurements on the cobalt ferrite nanoparticles are presented.

Abstract: Objective: To prepare and characterize the PEI-Fe3O4 nanosized magnetic complex and investigate the therapeutic effects of the PEI-Fe3O4 /survivin-siRNA magnetic complex combined with magnetic fluid hyperthermia (MFH) on human lung carcinoma cells . Methods: Fe3O4 magnetic nanoparticles (MNPs) were prepared by the technique of chemical co-precipitation and the surface of Fe3O4 MNPs was modified by PEI. Transmission electron microscope(TEM)，X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR) were applied to characterize the PEI-Fe3O4 magnetic complex. Thermodynamic test was used to observe temperature change of various concentration of Fe3O4 suspension under alternating magnetic field(AMF). The DNA binding efficiency of PEI-Fe3O4 was observrd by electrophoresis experiment. Transfection efficiency was determined by delivering reporter gene(pEGFP-encoding luciferase)to GLC-82 cell lines using PEI-Fe3O4 as a vector. Inhibitory effect of the expression of survivin mRNA in GLC-82 cells was detected by RT-PCR after transfection with PEI-Fe3O4/survivin-siRNA. The therapeutic effects of PEI-Fe3O4/survivin-siRNA combined with MFH on GLC-82 cells was evaluated by MTT test. Results: The prepared Fe3O4 MNPs and PEI-Fe3O4 magnetic complex were approximately spherical，high electron dense，good dispersibility uniform in size observed by TEM, with an average diameter of about 20 nm.The XRD pattern of the sample showed the characteristic peaks of their cubic spinel structure,The observed diffraction lines were found to correspond to those of a standard ferrite(Fe3O4) pattern. The results of FTIR demonstrated the adsorption effect of PEI. The corresponding suspension with different concentrations of Fe3O4 MNPs could rise to a steady temperature ranging from 42°C～59°C under AMF within 40 minutes and keep stable from then on. The PEI-Fe3O4 magnetic complex had good binding ability with DNA which could efficiently deliver the foreign gene to GLC-82 cell.Inhibitory ratio of survivin mRNA expressions by survivin-siRNA was 35.6%and MTT test assay showed that the cell growth inhibition rate(IR) of the combination therapy(58.71%) is higher than that(31.87%,28.45%) of the single therapy. Conclusion: The experiment results suggested that PEI-Fe3O4 magnetic complex was an novel non-virus gene vector, which has multiple benefits in combination of thermotherapy and gene therapy on lung carcinoma.

Abstract: Magnetic nano- and microparticles have already found many important applications in various areas of biosciences, medicine, biotechnology, environmental technology etc. These smart materials exhibit different types of response to external magnetic field. In most cases they can be described as composite materials, where the magnetic properties are caused by the presence of iron oxides nano- or microparticles. Such materials can be efficiently separated from difficult-to-handle samples and targeted to the desired place, applied as contrast agents for magnetic resonance imaging, used to generate heat during exposure to alternating magnetic field or to modify biomolecules and biological structures.