Department of Chemistry, Wuhan University, Wuhan 430072, China.
Biomacromolecules. 2010 Nov 8;11(11):2896-903. doi: 10.1021/bm100642y. Epub 2010 Oct 4.
We prepared magnetic cellulose porous microspheres (MCM) with mean diameter of ∼200 μm by employing the sol-gel transition (SGT) method from a mixture of magnemite ferrofluid and cellulose dissolved in 7 wt % NaOH/12% urea aqueous solvent precooled to -12 °C. Subsequently, the cellulose microspheres were activated with epoxy chloropropane to enhance loading efficiency of biomacromolecules. Their morphology, structure, and properties were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and vibrating-sample magnetometer. The results indicated that the spherical magnetic γ-Fe2O3 nanoparticles with mean size of 10 nm were uniformly dispersed and embedded in the cellulose substrate of MCM, and the structure and nature of γ-Fe2O3 were conserved perfectly. Penicillin G acylase (PGA) as a biocatalyst was immobilized successfully in the porous microspheres, as a result of the existence of the cavity and affinity forces in the activated cellulose matrix. The immobilized PGA exhibited highly effective catalytic activity, thermal stability, and enhanced tolerance to pH variations. Furthermore, the cellulose microspheres loaded with the enzymes could be removed and recovered easily by introducing a magnetic field, leading to an acceptable reusability. Therefore, we have provided a simple and biocompatible support for the enzyme immobilization, which will be promising for the applications in the biomaterial fields.
我们通过 sol-gel 转变（SGT）方法，从冷却至-12°C 的磁铁矿铁磁流体和溶解在 7wt%NaOH/12%尿素水溶液中的纤维素混合物中制备了平均直径约为 200μm 的磁性纤维素多孔微球（MCM）。随后，我们使用环氧氯丙烷对纤维素微球进行活化，以提高生物大分子的负载效率。我们使用傅里叶变换红外光谱、扫描电子显微镜、X 射线衍射和振动样品磁强计对其形态、结构和性能进行了表征。结果表明，平均粒径为 10nm 的球形磁性γ-Fe2O3 纳米粒子均匀分散并嵌入 MCM 的纤维素基质中，γ-Fe2O3 的结构和性质得到了完美的保留。青霉素 G 酰化酶（PGA）作为一种生物催化剂被成功地固定在多孔微球中，这是由于在活化的纤维素基质中存在空腔和亲和力。固定化 PGA 表现出高效的催化活性、热稳定性和增强的耐 pH 变化能力。此外，通过引入磁场，负载有酶的纤维素微球可以很容易地被去除和回收，具有良好的可重复使用性。因此，我们为酶固定化提供了一种简单且生物相容的载体，这在生物材料领域具有广阔的应用前景。
