Regulation of plasmid release from super paramagnetic gelatin microspheres in implant of porosity cage under oscillating magnetic field

To evaluate the value of super paramagnetic chitosan pDsVEGF165 Red1-N1 gelatin microsoheres (SPCPGM), the SPCPGM were prepared and characterized, the regulation of drug release in bone implant of porosity cage with oscillating magnetic fields in vitro were studied in this paper. The super paramagnetic (Fe 304) chitosan nanospheres (SPFCN) were synthesized by means of chemical co-precipitation and then the super paramagnetic (Fe 304) chitosan plasmids (pDsVEGF165 Red1-N1) gelatin microspheres were prepared by means of crosslinking solidify. The plasmids release test of SPCPGM in bone implant of porosity cage was done in 0.01 M phosphate buffer at 37degC (pH 7.4) , with or without oscillating magnetic fields. The concentration of plasmids was measured with UV spectro-photometer. In our in vitro experiment, we showed oscillating magnetic field could promote drug release of SPCPGM repeatedly. Compare with chitosan pDsVEGF165 Red1-N1 gelatin microsoheres (CPGM), the amount of cumulative release reaches up to 4-fold at the 25 th day. We also showed the oscillating magnetic fields could promote drug release of SPCPGM repeatedly and the periods of controlled release of this system was more than 3 weeks.