Homogeneous and high-density immobilization of proteins on gold-based sensing surface without the loss of protein activity is of great significance for high-performance immunosensing but remains challenging. To realize more sensitive immunosensing, an improved method for protein immobilization on the gold surface is urgently required. Here, we propose a biological and mild approach by combining a genetically encoded SpyTag–SpyCatcher interaction system with a redesigned S-layer of bacteria. This method allows proteins of interest to be covalently linked with the S-layer in a biological manner and arranged orderly in a two-dimensional nanoarray on the gold surface. The activity of African swine fever virus proteins was significantly preserved after immobilization. In addition, our S-layer-based immobilization method exhibited an eightfold increase in detection sensitivity compared with the conventional chemical cross-linking for protein immobilization during serological tests. Together, our S-layer-based immobilization method provides an innovative approach for building a quality gold-based biosensing interface and should greatly contribute to the high-sensitivity sensing for a deeper understanding of pathogen infection and host immunity.

中文翻译：

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二维蛋白质纳米阵列作为金基免疫传感系统传感元件的载体

在不损失蛋白质活性的情况下将蛋白质均匀且高密度地固定在金基传感表面上对于高性能免疫传感具有重要意义，但仍然具有挑战性。为了实现更灵敏的免疫传感，迫切需要一种改进的蛋白质固定在金表面的方法。在这里，我们通过将遗传编码的 SpyTag-SpyCatcher 交互系统与重新设计的 S 层细菌相结合，提出了一种生物学和温和的方法。该方法允许感兴趣的蛋白质以生物方式与 S 层共价连接，并在金表面上以二维纳米阵列有序排列。非洲猪瘟病毒蛋白的活性在固定化后得到显着保留。此外，与血清学测试中用于蛋白质固定的传统化学交联相比，我们基于 S 层的固定方法的检测灵敏度提高了八倍。总之，我们基于 S 层的固定化方法为构建高质量的金基生物传感界面提供了一种创新方法，并且应该极大地促进高灵敏度传感，以更深入地了解病原体感染和宿主免疫。