A label-free optical sensor system on silicon: Determining the thermodynamic and kinetic quantities of protein-ligand interactions

使用自由空间光学的光学无标签生物传感器，如表面等离子体共振装置，已经成功进入市场。同时，显而易见的是，用于光学无标签生物传感的芯片集成解决方案具有许多优点，例如显著减小尺寸，使大量传感器元件能够在小芯片上实现，高度并行操作，以及对生物材料的最小需求。在这项提案中，一个多学科的方法汇集了硅光子学、化学和生物化学方面的专业知识。总体目标是开发一种硅基光学生物传感器系统，用于高度并行的分析和必要的化学，以获得一个真实世界的生物传感器系统，用于多种生物蛋白质-配体相互作用的并行实时测量。Petermann/Bruns小组带来了他们在硅光子学方面的知识，Rück-Braun小组带来了硅表面化学包括分析的专业知识，Volkmer小组引入了生物模型，在此基础上生物传感器可以进行优化和广泛的测试。传感器本身将在SOI(硅上绝缘体)中实现。我们将著名的环形谐振器作为传感元件与一种基于热光调制的大规模并行传感的新方法相结合。为了最大限度地提高传感器的适用性，将开发一种用于大型动态传感的新结构。此外，为了获得最适合我们应用的解决方案，将对传感器结构进行几种变化，如波导型和环形。在生化方面，将使用已建立的硅表面化学和描述良好的蛋白质-配体相互作用来对传感器系统进行功能化和验证。使用微流控技术，将对所研究的生物相互作用进行平行定量亲和力测量。将建立与温度相关的测量来确定热力学参数，如吉布斯自由能、热焓、熵和反应活化能。最后，我们将研究非常具有挑战性的蛋白质-蛋白质相互作用化学计量学的测定。我们将尝试使用我们的无标记生物传感器系统来确定蛋白质复合体的低聚状态。这个生物传感器系统将使我们有可能通过一次实验来确定蛋白质-配体相互作用的热力学、动力学和化学计量参数。

Optical label-free biosensors using free-space optics like surface plasmon resonance devices have successfully entered the market. Meanwhile it becomes clear that chip-integrated solutions for optical label-free biosensing feature many advantages like significant size reduction enabling a large number of sensor elements on a small chip, highly parallel operation and a minimal demand of biomaterial. In this proposal a multidisciplinary approach brings together the expertise in silicon photonics, chemistry and biochemistry. The overall goal is to develop a silicon based optical biosensor system for highly parallel assays and the necessary chemistry to get a real world biosensor system for parallel real time measurements of several kinds of biological protein-ligand interactions.The group of Petermann/Bruns brings in their knowledge on silicon photonics, the group of Rück-Braun the expertise on silicon surface chemistry including analysis, and the group of Volkmer brings in the biological models on which the biosensor can be optimized and tested extensively.The sensor itself will be realized in SOI (silicon-on-insulator). We combine well known ring resonators as sensing elements with a new approach for massive parallel sensing based on thermo-optical modulation. To maximize the applicability of the sensor, a new structure for large dynamic sensing will be developed. Furthermore, to achieve the best solution for our applications, several variations of the sensor structure like waveguide type and ring shape will be performed.On the biochemical side, established silicon surface chemistry and well described protein-ligand interactions will be used to functionalize and verify the sensor system.Using microfluidics, parallel quantitative affinity measurements of the biological interactions under investigation will be performed. Temperature dependent measurements will be established to determine the thermodynamic parameters such as Gibbs free energy, enthalpy, entropy and reaction activation energy. Finally, the very challenging determination of the protein-protein interaction stoichiometry will be investigated. We will try to determine the oligomeric state of a protein complex using our label-free biosensor system. This biosensor system will give us the possibility to determine the thermodynamic, kinetic and stoichiometric parameters of protein-ligand interactions with a single experimental run.