Yang Tao, Li Zhuang, Wang Li, Guo Cunlan, Sun Yujing
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022, P. R. China.
Langmuir. 2007 Oct 9;23(21):10533-8. doi: 10.1021/la701649z. Epub 2007 Sep 15.
Lysozyme monolayer-protected gold nanoparticles (Au NPs) which are hydrophilic and biocompatible and show excellent colloidal stability (at low temperature, ca. 4 degrees C), were synthesized in aqueous medium by chemical reduction of HAuCl4 with NaBH4 in the presence of a familiar small enzyme, lysozyme. UV-vis spectra, transmission electron microscopy (TEM), atomic force microscopy, and X-ray photoelectron spectroscopy characterization of the as-prepared nanoparticles revealed the formation of well-dispersed Au NPs of ca. 2 nm diameter. Moreover, the color change of the Au NP solution as well as UV-vis spectroscopy and TEM measurements have also demonstrated the occurrence of Ostwald ripening of the nanoparticles at low temperature. Further characterization with Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering indicated the formation of a monolayer of lysozyme molecules on the particle surface. FTIR data also indicated the intactness of the protein molecules coated on Au NPs. All the characterization results showed that the monodisperse Au NPs are well-coated directly with lysozyme. Driven by the dipole-dipole attraction, the protein-stabilized Au NPs self-assembled into network structures and nanowires upon aging under ambient temperature. On the basis of their excellent colloidal stability, controlled self-assembly ability, and biocompatible surface, the lysozyme monolayer-stabilized Au NPs hold great promise for being used in nanoscience and biomedical applications.
溶菌酶单层保护的金纳米颗粒（Au NPs）具有亲水性和生物相容性，并且在低温（约4℃）下表现出优异的胶体稳定性。通过在常见的小酶溶菌酶存在下，用NaBH4化学还原HAuCl4，在水介质中合成了该纳米颗粒。对所制备的纳米颗粒进行紫外-可见光谱、透射电子显微镜（TEM）、原子力显微镜和X射线光电子能谱表征，结果表明形成了直径约为2 nm的分散良好的Au NPs。此外，Au NP溶液的颜色变化以及紫外-可见光谱和TEM测量也证明了纳米颗粒在低温下发生了奥斯特瓦尔德熟化。用傅里叶变换红外光谱（FTIR）和动态光散射进行的进一步表征表明，在颗粒表面形成了溶菌酶分子的单层。FTIR数据还表明包覆在Au NPs上的蛋白质分子是完整的。所有表征结果表明，单分散的Au NPs被溶菌酶很好地直接包覆。在偶极-偶极吸引力的驱动下，蛋白质稳定的Au NPs在室温下老化时自组装成网络结构和纳米线。基于其优异的胶体稳定性、可控的自组装能力和生物相容性表面，溶菌酶单层稳定的Au NPs在纳米科学和生物医学应用中具有巨大的应用前景。
