微生物角蛋白酶在纳米粒子制备中的应用

金纳米粒子传统制备主要采用物理或化学方法，存在着过程复杂、条件苛刻、化学试剂用量高等缺点，而生物法由于环境友好、作用条件温和等特性逐步受到关注。本研究利用角蛋白酶的还原性制备金纳米粒子，恒温反应，分别对反应过程中氯金酸浓度、酶添加量和反应时间三个因素进行优化，并通过动态光散射（DLS）、zeta电位分析、透射电镜（TEM）及红外吸收光谱（FTIR）对制备的金纳米粒子进行表征。结果表明：在1mmol/L的氯金酸溶液中加入1400U角蛋白酶，反应5h得到的金纳米胶体在550nm左右的吸收峰最显著，反应收率达到85%。红外吸收光谱分析显示3100~3500cm^-1处的酰胺N—H键的不对称伸缩振动峰和1650cm^-1处的酰胺Ⅰ带，证明角蛋白酶本身参与了金纳米粒子的合成，所得纳米金的粒径在30nm以下，zeta电位值为-13mV，粒子之间没有聚集。该方法具有良好的稳定性和可操作性，为金纳米粒子的绿色化制备提供了一种新途径。

Application of microbial keratinase in biopreparation of AuNPs

Gold nanoparticles are traditionally prepared by the physical or chemical methods, which have disadvantages such as complex process, harsh conditions and high chemical reagent consumption, and biological method has been paid more and more attention due to its low pollution and mild operating conditions. In this study, gold nanoparticles were prepared by the reductive property of keratinase. Three factors including the concentration of chloroauric acid solution, the amount of enzyme added and the reaction time were optimized. The gold nanoparticles were characterized by dynamic light scattering (DLS), zeta potential analysis, transmission electron microscopy (TEM) and infrared absorption spectroscopy (FTIR). When adding 1400U of keratinase to 1mmol/L chloroauric acid solution and after 5h, the absorption peak of gold nanoparticles obtained was the most significant at about 550nm and the reaction yield reached 85%. The amide Ι bond at 1650cm^-1 and the amino bond N—H between 3100~3500cm^-1 in the spectra demonstrated that the keratinase was involved in the synthesis of gold nanoparticles. The measured size of gold nanoparticles was less than 30nm, the zeta potential value was -13mV and there was no aggregation between particles. The method has good operability and stability, which provides a new way for green preparation of gold nanoparticles.