Dual-modality field-effect/magnetic immunosensor chip for label-free biomarker detection (FEMIC)

该项目的主要目标是开发一种可重复使用的双模场效应/磁性免疫传感器芯片，用于检测多个生物标志物。半导体场效应平台非常适合利用生物标志物的分子电荷进行无标记的电检测，而混频磁检测是一种非接触式的检测磁性纳米颗粒(MNPs)结合状态的技术。这种使用两种完全不同的换能器原理的组合免疫传感器将大大减少可能的错误信号，从而提供更可靠的靶标记物检测。只有当两种方法记录的信号沿预期方向变化时(布尔逻辑与门)，结果才被认为是积极的。建议的概念提供的优点包括：-使用简单的免疫敏感场效应电容器作为换能器，容易和低成本地制造免疫芯片；-使用MNPs不仅用于磁检测，而且用于捕获和分离样品中的目标生物标记物及其在免疫芯片表面的浓度；-在低离子强度和高离子强度的样品中都能检测生物标记物；-由于免疫化学反应事件与传感表面分离，生物分子不会非特异性地吸附在免疫芯片表面；-使用同一免疫芯片检测多个生物标记物的可重用性和可能性；-磁体加速生物标记物-抗体结合的MNPs的吸附并缩短产生结果的时间。迄今为止，用MNPs修饰的免疫FEC尚未被用于无标记检测蛋白质生物标记物的固有分子电荷。新的方法将被示范地用于检测几个临床相关的生物标志物(例如糖化血红蛋白、血红蛋白、C反应蛋白)。由亲水性涂层稳定的MNPs将被合成出不同尺寸的MNPs，并根据其非线性磁响应进行表征。它们将与抗体结合，进行特定的生物标记物检测。免疫FECs的物理和电化学表征将为生物标志物-抗体结合的MNPs的表面修饰和再生步骤提供信息。用生物标记物-抗体偶联的MNPs修饰免疫FEC的理论模型将被开发出来。基本工作特性(灵敏度、检测限、特异性、可重用性等)将对双模式免疫芯片进行系统的研究，并与理论预测进行比较。该提议可能会产生明显的影响，将场效应和磁场检测原理结合在一起，用于未来可能的诊断工具，如医疗保健应用。计划中的合作使这种多学科方法的目标导向工作成为可能，并将互补的科学专业知识完美结合在一起。

The main objective of the proposed project is the development of a reusable dual-modality field-effect/magnetic immunosensor chip for detection of multiple biomarkers. The semiconductor field-effect platform is very well-suited for label-free electrical detection of biomarkers by their molecular charge, whereas frequency mixing magnetic detection is a contactless technique probing the binding state of magnetic nanoparticles (MNPs). Such a combined immunosensor using two completely different transducer principles will drastically reduce possible false signals and thus, will provide a more reliable detection of target biomarkers. Only if signals recorded by both methods change in expected direction (Boolean logic AND gate), the result will be considered as positive.Advantages provided by the proposed concept include:- easy and low-cost fabrication of immunochips by using a simple immuno-sensitive field-effect capacitor (ImmunoFEC) as transducer;- the use of MNPs not only for magnetic detection but also for capturing and separation of target biomarkers from samples and their concentration on the immunochip surface;- capability for detection of biomarkers in both low- and high-ionic strength samples;- absence of non-specific adsorption of biomolecules on the ImmunoFEC surface because the immunochemical reaction event is separated from the sensing surface;- reusability and possibility of detection of multiple biomarkers using the same immunochip;- acceleration of adsorption of biomarker-antibody-conjugated MNPs by the magnet and a reduced time-to-result.ImmunoFECs modified with MNPs have not been used for label-free detection of protein biomarkers by their intrinsic molecular charge so far. The new approach shall be exemplarily examined for the detection of several clinically relevant biomarkers (e.g., glycated hemoglobin, hemoglobin, C-reactive protein). MNPs stabilized by hydrophilic coatings will be synthesized in different sizes and characterized according to their nonlinear magnetic responses. They will be conjugated with antibodies for specific biomarker detection. Physical and electrochemical characterization of ImmunoFECs will provide information on surface modification with biomarker-antibody-conjugated MNPs and regeneration steps. A theoretical model of how the ImmunoFEC modified with biomarker-antibody-conjugated MNPs works will be developed. Basic working characteristics (sensitivity, detection limit, specificity, reusability, etc.) of the dual-modality immunochip will be systematically studied and compared with theoretical predictions.The proposal might have distinct impact bringing field-effect and magnetic detection principle together for possible future diagnostic tools such as point-of-care applications. The intended collaboration enables target-oriented work on this multidisciplinary approach and combines complementary scientific expertise in a perfect match.