Optical biosensor based on weak value amplification for the high sensitivity detection of Pertuzumab in combination with Trastuzumab binding to the extracellular domain of HER2

A real-time optical phase sensing scheme based on weak value amplification was proposed to monitor the especially binding process of Pertuzumab combined with Trastuzumab on HER2 positive cells. From the wavelength shift of output spectrum, the phase difference between measuring and referential path related to the concentration of Pertuzumab as well as Trastuzumab could be calculated. With this approach, the limit of detection (LOD) of 5.54 × 10−13 M for Pertuzumab assay was achieved. Besides, the kinetics signal of Pertuzumab in combination with Trastuzumab binding to HER2 was detected in real time. Experimental results demonstrated that both Trastuzumab and Pertuzumab can be captured by HER2, but the former was significantly superior to the latter in terms of the target number. Additionally, the binding speed was analyzed and demonstrated to be closely correlated with the initial concentration of the targeting agents.