两种氨基修饰的四氧化三铁磁性纳米颗粒的制备与表征

Preparation and Characterization of Two Different Amino-modified Iron Oxide Magnetic Nanoparticles and Determination of the Amount of Amino on Nanoparticle Surface

目的用化学共沉淀法制备了四氧化三铁(Fe_3O_4)磁性纳米颗粒并进行氨基修饰和定量。方法分别采用"将磁颗粒包覆硅壳后修饰氨基"和"直接修饰氨基"两种不同方法对磁性纳米颗粒的表面进行氨基修饰,并通过对硝基苯甲醛比色法对表面氨基进行定量,比较两种方法的修饰效果。通过透射电子显微镜(TEM)、傅立叶变换红外光谱仪(FTIR)、震动样品磁强计(VSM)对其进行表征。结果所合成的颗粒粒径比较均一,包覆的硅壳在6 nm左右,且具有超顺磁性,在外加磁场作用下能够实现快速有效的分离。氨基定量结果显示有硅壳包覆的磁颗粒的氨基量明显多于3-氨基丙基三乙氧基硅烷(APTES)直接修饰磁颗粒的氨基量。结论有硅壳包覆的磁性纳米颗粒更适合进行下一步的生物功能化修饰,能够适应更广泛的生物应用。

Objective To obtain Fe304 magnetic nanoparticles by chemical co-precipitation method and modifiy them by amino groups which have been quantified. Methods Two different amino-modified Fe304 magnetic nanoparticles were obtained using two different modification methods： amino-modification after nanoparticles are coated by silicon and direct amino-modification respectively. The nanoparticles were characterized by transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （ FTIR）, and vibration sample magnetic machine （VSM）. The amount of amino group modified on the surface was determined by colorimetric method that involved amino reacting with p-nitrobenzaldehyde. Results The TEM results indicated that the particle size was relatively uniform and the silica shell was about 6nm. Moreover, the magnetic nanoparticles were superparamagnetic and could be separated in a magnetic field quickly and effectively. We compared the two methods and the results showed there was much more amine on the surface of Fe3O4 coated by silica than that by direct amino-modification. Conclusion The magnetic nanoparticles coated with silicon shell are more suitable for the next step of biological functional modification and can be used in a wider range of biological applications.