ABSTRACT Optical biosensors provide a platform for qualitatively and quantitatively analyzing various biomolecular interactions. In addition to advantages such as label-free and high-throughput detection, these devices are also capable of measuring real-time binding curves in response to changes in optical properties of biomolecules. These kinetic data may be fitted to models to extract binding affinities such as association rates, dissociation rates, and equilibrium dissociation constants. In these biosensors, one of the binding pair is usually immobilized on a solid substrate for capturing the other. Due to the nature of these surface-based methods, mass transport effects and immobilization heterogeneity may cause problems when fitting the kinetic curves with the simple one-to-one Langmuir model. Here, real-time binding curves of various antibody–antigen reactions were obtained using an ellipsometry-based biosensor, and the results were fitted to the simple one-to-one model as well as a more sophisticated approach. The results show that the one-to-two model fitted much better to the curves than the one-to-one model. The two-site model may be explained by assuming two immobilization configurations on the surface. In summary, in fitting real-time curves obtained from optical biosensors, more sophisticated models are usually required to take surface-related issues, such as immobilization heterogeneity, and mass transport effects within targets, into account.

中文翻译：

---

使用无标记光学生物传感器评估动力学

摘要 光学生物传感器为定性和定量分析各种生物分子相互作用提供了一个平台。除了无标记和高通量检测等优势外，这些设备还能够测量响应生物分子光学特性变化的实时结合曲线。这些动力学数据可以拟合模型以提取结合亲和力，例如结合速率、解离速率和平衡解离常数。在这些生物传感器中，结合对中的一个通常固定在固体基质上以捕获另一个。由于这些基于表面的方法的性质，在使用简单的一对一朗缪尔模型拟合动力学曲线时，质量传递效应和固定异质性可能会导致问题。这里，使用基于椭圆光度法的生物传感器获得各种抗体 - 抗原反应的实时结合曲线，并将结果拟合到简单的一对一模型以及更复杂的方法中。结果表明，一对二模型比一对一模型更适合曲线。双位点模型可以通过假设表面上的两个固定配置来解释。总之，在拟合从光学生物传感器获得的实时曲线时，通常需要更复杂的模型来考虑与表面相关的问题，例如固定异质性和目标内的质量传输效应。结果表明，一对二模型比一对一模型更适合曲线。双位点模型可以通过假设表面上的两个固定配置来解释。总之，在拟合从光学生物传感器获得的实时曲线时，通常需要更复杂的模型来考虑与表面相关的问题，例如固定异质性和目标内的质量传输效应。结果表明，一对二模型比一对一模型更适合曲线。双位点模型可以通过假设表面上的两个固定配置来解释。总之，在拟合从光学生物传感器获得的实时曲线时，通常需要更复杂的模型来考虑与表面相关的问题，例如固定异质性和目标内的质量传输效应。