Silicon‐Based Integrated Label‐Free Optofluidic Biosensors: Latest Advances and Roadmap

Abstract By virtue of the well‐developed micro‐ and nanofabrication technologies and rapidly progressing surface functionalization strategies, silicon‐based devices have been widely recognized as a highly promising platform for the next‐generation lab‐on‐a‐chip bioanalytical systems with a great potential for point‐of‐care medical diagnostics. Herein, an overview of the latest advances in silicon‐based integrated optofluidic label‐free biosensing technologies relying on the efficient interactions between the evanescent light field at the functionalized surface and specifically bound analytes is presented. State‐of‐the‐art technologies demonstrating label‐free evanescent wave‐based biomarker detection mainly encompass three device configurations, including on‐chip waveguide‐based interferometers, microring resonators, and photonic‐crystal‐based cavities. Moreover, up‐to‐date strategies for elevating the sensitivities and also simplifying the sensing processes are discussed. Emerging laboratory prototypes with advanced integration and packaging schemes incorporating automatic microfluidic components or on‐chip optoelectronic devices lead to one significant step forward in real applications of decentralized diagnostics. Besides, particular attention is paid to currently commercialized label‐free optical bioanalytical models on the market. Finally, the prospects are elaborated with several research routes toward chip‐scale, low‐cost, highly sensitive, multi‐functional, and user‐friendly bioanalytical systems benefiting to global healthcare.