高Fe_3O_4含量微米尺寸磁性复合微球的合成及其在化学发光免疫检测中应用初探

PREPARATION AND BIO-APPLICATION OF MONODISPERSE COMPOSITE MICROSPHERES WITH HIGH Fe_3O_4 CONTENT

采用种子乳液聚合方法制得了微米尺度的高磁性物质含量的磁性复合微球.聚合体系中,以0.7～0.8μm的Fe3O4磁性聚集体细乳液作为种子,将苯乙烯,二乙烯基苯作为聚合单体加入到磁性聚集体细乳液中,对Fe3O4磁性聚集体进行溶胀后进行聚合.研究了聚合过程中,溶胀时间对复合微球形貌和磁性物质含量的影响,获得系列形貌微球.通过透射电镜(TEM)、热重分析(TGA)、红外分析(FTIR)、振动样品磁强计(VSM)等表征手段对所制备的磁性聚合物微球进行分析表征.结果显示,所得到的磁性聚合物微球粒度为0.7～1μm,尺寸分布较均一,具有超顺磁性,磁性物质含量为29wt%～57wt%.然后又通过丙烯酸和苯乙烯共聚对微球表面羧基功能化后,得到了表面羧基密度为0.92mmol/g的微球,再将所制备的微球与生物分子偶联后(以hCG作为模式待检分子),在化学发光免疫检测上进行了初步的应用,取得到了较好的应用结果.

Monodisperse superparamagnetic polymer composite microspheres with high magnetite content were prepared by seed emulsion co-polymerization. In this system,0. 7 ～ 0. 8 μm Fe3O4 magnetic aggregation droplets which were consisting of Fe3O4 nanoparticles with an average particle size of 10 nm were severed as seeds and droplets of styrene and divinylbenzene were used as monomers to swell the seeds before the polymerization. The influence of the swelling time on the morphology and magnetite nanoparticles content of the composite microspheres was also investigated. The obtained microspheres with diameter of 0. 7 ～ 1. 0 μm were superparamagnetic and with the magnetite nanoparticles content of 29 wt% ～ 57 wt% ,which were extensively characterized by transmission electron microscopy （ TEM ）,thermo-gravimetric analysis （ TGA ）,Fourier transform infrared spectrometer （FTIR） and vibrating sample magnetometer （VSM）. By adjusting the swelling time,a series of microspheres with different morphologies were also obtained and characterized. The result indicated that the degree of phase separation of the obtained microspheres increased when the swelling time decreased. On the other hand,the carboxyl group was introduced onto the surface of the above magnetic microspheres via a two-step seed emulsion co-polymerization using acrylic acid as a functional polymeric monomer. After that,the as synthesized superparamagnetic polymer composite microspheres with carboxyl groups （the density of carboxyl group was about 0. 92 mmol /g beads） were conjugated with the bio-molecules （hCG was used as a model detection of bio-molecules in this study ） and then applied into the chemiluminescence immunoassay. The obtained well performance showed the feasibility of the microsphere to be used as a potential and promising material for bio-detection.