Objective      To explore how to prepare mannose-modified superparamagnetic iron oxide nanoparticles (SPION) and investigate the physical properties in vitro.      Methods      Co-precipitation was applied to prepare iron oxide nanoparticles. Then mannose was added to the solution to prepare the mannose-SPION under high-speed mechanical stirring at 90 ℃ for 2 h. The size and distribution of the obtained nanoparticles were measured by transmission electron microscopy (TEM). Fourier

transform infrared spectroscopy (FTIS) was used to evaluate the modification of mannose. Atomic absorption spectrophotometry (AAS) was employed to measure the iron content in the samples. Whether the granules were fully engulfed were measured by phagocytic white blood cells in vitro test. The safety of the nanoparticles were measured by cell toxicity test.      Results      The mannose-SPION was in globular or spherical shape

and in good dispersion. The cores were Fe

3

O

4

with an average core diameter of (12.89±3.29) nm. The hole diameter of the mannose-SPION was lesser than 20 nm. The iron content of sample was 69.84 mg/L. The result of FTIS indicated that the surface of Fe

3

O

4

had mannose. The phagocytosis test showed that mannose-SPION had higher rate of phagocytosis. The cytotoxicity test displayed that the IC

50

of mannose-SPION for cell was 100.44 μg/ml.      Conclusion      The mannose-SPION possess the characteristics of small size

good dispersion super-paramagnetic response and lower cytotoxicity

and can be phagocytized by phagocyte.