Fang Ye, Ferrie Ann M, Fontaine Norman H, Mauro John, Balakrishnan Jitendra
Biochemical Technologies, Science and Technology Division, Corning Incorporated, Corning, New York 14831, USA.
Biophys J. 2006 Sep 1;91(5):1925-40. doi: 10.1529/biophysj.105.077818. Epub 2006 Jun 9.
This article presents theoretical analysis and experimental data for the use of resonant waveguide grating (RWG) biosensors to characterize stimulation-mediated cell responses including signaling. The biosensor is capable of detecting redistribution of cellular contents in both directions that are perpendicular and parallel to the sensor surface. This capability relies on online monitoring cell responses with multiple optical output parameters, including the changes in incident angle and the shape of the resonant peaks. Although the changes in peak shape are mainly contributed to stimulation-modulated inhomogeneous redistribution of cellular contents parallel to the sensor surface, the shift in incident angle primarily reflects the stimulation-triggered dynamic mass redistribution (DMR) perpendicular to the sensor surface. The optical signatures are obtained and used to characterize several cellular processes including cell adhesion and spreading, detachment and signaling by trypsinization, and signaling through either epidermal growth factor receptor or bradykinin B2 receptor. A mathematical model is developed to link the bradykinin-mediated DMR signals to the dynamic relocation of intracellular proteins and the receptor internalization during B2 receptor signaling cycle. This model takes the form of a set of nonlinear, ordinary differential equations that describe the changes in four different states of B2 receptors, diffusion of proteins and receptor-protein complexes, and the DMR responses. Classical analysis shows that the system converges to a unique optical signature, whose dynamics (amplitudes, transition time, and kinetics) is dependent on the bradykinin signal input, and consistent with those observed using the RWG biosensors. This study provides fundamentals for probing living cells with the RWG biosensors, in general, optical biosensors.
本文介绍了利用共振波导光栅（RWG）生物传感器来表征刺激介导的细胞反应（包括信号传导）的理论分析和实验数据。该生物传感器能够检测细胞内容物在垂直和平行于传感器表面的两个方向上的重新分布。这种能力依赖于通过多个光学输出参数在线监测细胞反应，包括入射角的变化和共振峰的形状。虽然峰形的变化主要是由于刺激调节的细胞内容物在平行于传感器表面方向上的不均匀重新分布，但入射角的变化主要反映了刺激引发的垂直于传感器表面的动态质量重新分布（DMR）。获取了光学特征并用于表征几种细胞过程，包括细胞粘附与铺展、胰蛋白酶消化引起的脱离与信号传导，以及通过表皮生长因子受体或缓激肽B2受体的信号传导。建立了一个数学模型，将缓激肽介导的DMR信号与细胞内蛋白质的动态重新定位以及B2受体信号传导周期中的受体内化联系起来。该模型采用一组非线性常微分方程的形式，描述了B2受体的四种不同状态、蛋白质和受体 - 蛋白质复合物的扩散以及DMR反应的变化。经典分析表明，该系统收敛到一个独特的光学特征，其动力学（幅度、转变时间和动力学）取决于缓激肽信号输入，并且与使用RWG生物传感器观察到的结果一致。总体而言，这项研究为使用RWG生物传感器（即光学生物传感器）探测活细胞提供了基础。
