OICC Press International Journal of Biophotonics and Biomedical Engineering (IJBBE) 2980-9037 1 1 2021 07 01 Designing real-time biosensors and chemical sensors based on symmetrical photonic crystal heterostructures 21 28 10.30495/ijbbo.2021.689422 EN Maryam Sharifi Faculty of physics, Tabriz University, Tabriz, Iran Habib Tajalli Biophotonics Research Center,Tabriz Branch, Islamic Azad University, Tabriz, Iran Hamid Pashaei Adl Instituto de Ciencia de los Materiales, University of Valencia, 46980 Valencia, Spain Payman Tajalli Institut für Theoretische Physik, Universität Regensburg, 930400, Regensburg, Germany Journal Article 2021 07 01 In this paper, we introduce and analytically demonstrate a novel biosensor based on the light-matter interaction in a classic topological photonic crystal (PC) heterostructure, which consists of two opposite-facing 5-period PCs separated by a microfluidic channel. Because of the excitation of topological edge mode (TEM) at the interface of the two PCs, the strong coupling between incident light and TEM produces a high-quality resonance peak, which can be used to detect very small changes in the refractive index of biomaterials such as Jurkat Cells inside the microfluidic channel. The proposed biosensor has a sensitivity as high as 240 nm/RIU and figure of merit (FOM) higher than 250.