Abstract:

BACKGROUND: Common superparamagnetic iron oxide nanoparticles (SPIO) have limitations to apply to the reticuloendothelial system (RES) rather than non-RES.
OBJECTIVE: To study the preparation and physico-chemical property of long-circulating SPIO liposome nanoparticles as novel MR contrast agent.
METHODS: The long-circulating SPIO liposome nanoparticles were prepared by three steps: ①preparation of long-circulating blank liposomes by film dispersion method, using DSPG and DSPE-PEG2000 with a molar ratio of 20∶1; ②synthesis of lauric acid-stabilized SPIO nanoparticles; ③the two products above were dialyzed for 3 days. Then, physico-chemical property of long-circulating SPIO liposome nanooparticles was measured.
RESULTS AND CONCLUSION: ①Lauric acid-stabilized SPIO nanoparticles, long-circulating blank liposomes and long-circulating SPIO liposomes appeared as circular particles with uniform size approximately 12 nm, 20 nm, 60 nm, respectively in the electron microscope. ②XRD analysis of SPIO nanoparticles: lauric acid-stabilized SPIO nanoparticles and long-circulating SPIO liposomes nanoparticles were face-centered cubic spinel structure of Fe3O4, and the crystalline particles were in good form. ③With the Malvern-3000HS, the measurements of long-circulating SPO liposomes were: di = 78.7 nm, peak area: 100%, peak number 1, dv = 76.7 nm, peak area: 100%, peak number 1, dn = 73.5 nm, peak area: 100%, peak number 1, polydispersity coefficient: 0.212. ④Standard curve of iron: A=0.194 7C+0.000 8, R2=0.998 2. The Fe concentration of long-circulating SPIO liposome was 6.721 3 g/L. ⑤As the iron concentration increases, T2 values of long-circulating SPIO liposome gradually decreased. Long-circulating SPIO liposomes were prepared with suitable sizes and distribution, and could be made into contrast agent for subcutaneous or intravenous injection.