Integrated optical bimodal waveguide biosensors: Principles and applications

Integrated optical biosensors have become one of the most compelling technologies for the achievement of highly sensitive, multianalyte, portable and easy to use point -of -care (POC) devices with tremendous impact in healthcare and environmental protection, among other application fields. In this context, bimodal waveguide (BiMW) interferometers have emerged over the last years as a powerful biosensor technology providing the benefits of extreme sensitivity under a label -free scheme, reliability and robustness within a highly compact footprint that can be integrated and multiplexed in lab -on -a -chip (LOC) platforms. In this review, we provide an overview of the state-of-the-art about integrated optical BiMW biosensors from the theoretical fundamentals to their practical implementation. Furthermore, we explore recent advances such as novel designs, integration in specific LOC systems and its application in real biosensing scenarios. Final remarks and perspectives on the potential impact of these biosensor interferometric structures are also provided, as well as some limitations that must be addressed in next steps.