Recent developments in optical biosensors based on integrated photonic devices are reviewed with a special emphasis on silicon-on-insulator ring resonators. The review is mainly devoted to the following aspects: (1) Principles of sensing mechanism. (2) sensor design. (3) biofunctionalization procedures for specific molecule detection and (4) system integration and measurement set-ups. https://hollandscountryclothinges.shop/product-category/fleece-trousers/