Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China.
Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China.
Int J Biol Macromol. 2018 Oct 15;118(Pt A):1004-1012. doi: 10.1016/j.ijbiomac.2018.06.181. Epub 2018 Jun 30.
Herein, the zwitterionic material poly (carboxybetaine acrylamide) was grafted onto iron oxide to obtain biocompatible magnetic nanoparticles FeO-pCBAA which were employed to immobilize enzymes. The nanocomplxes FeO-pCBAA were characterized using scanning electron microscopy (SEM), dynamic light scattering (DLS), zeta potential, Fourier transform-infrared (FT-IR) spectra and energy dispersive X-ray spectrometry (EDX). The urease as a model enzyme was immobilized with the novel supports and the properties of immobilized urease were further investigated in comparison with the free urease counterpart. The immobilized urease exhibited excellent thermodynamic and chemical stability. Particularly, 60% of initial activity was remained after being stored at 70 °C for 2 h while the free urease only remained 30%. Besides, the relative activity of immobilized enzyme was 1.7 times that of free ones after disposed in ethanol and 2-propanol for 2 h, and 7 times in DMF. Moreover, immobilized urease retained >80% of its initial activity after 5 cycles. In addition, the immobilization carrier FeO-pCBAA displayed famous biocompatibility, and the immobilized urease performed better in complex biological samples, which were >85% and <60% of its initial activity for the immobilized and dissociative urease, respectively, in 20% and 25% of serum. These results confirm that the nanoparticles FeO-pCBAA are biofriendly and efficient supports for enzyme immobilization and potential for practical applications in bio-microenvironments.
本文中，两性离子材料聚（羧基甜菜碱丙烯酰胺）被接枝到氧化铁上，得到了具有生物相容性的磁性纳米粒子 FeO-pCBAA，可用于固定酶。通过扫描电子显微镜（SEM）、动态光散射（DLS）、Zeta 电位、傅里叶变换红外（FT-IR）光谱和能谱（EDX）对纳米复合物 FeO-pCBAA 进行了表征。新型载体固定化脲酶，进一步研究了固定化脲酶的性质，并与游离脲酶进行了比较。固定化脲酶表现出优异的热力学和化学稳定性。特别是，在 70°C 下储存 2 小时后，仍保留初始活性的 60%，而游离脲酶仅保留 30%。此外，在乙醇和 2-丙醇中处理 2 小时后，固定化酶的相对活性是游离酶的 1.7 倍，在 DMF 中则是 7 倍。此外，固定化脲酶经过 5 次循环后仍保留其初始活性的>80%。此外，固定化载体 FeO-pCBAA 表现出良好的生物相容性，固定化脲酶在复杂的生物样品中表现更好，在 20%和 25%的血清中，固定化和游离脲酶的初始活性分别为>85%和<60%。这些结果证实了纳米粒子 FeO-pCBAA 是酶固定化的生物友好且高效的载体，在生物微环境中具有实际应用的潜力。
