Mussel inspired polydopamine surface chemistry as a one step method for bioreceptor immobilisation on silicon photonic biosensors

Silicon photonic biosensors are exciting candidates for the development of near-patient diagnostic tests because of advantages such as high sensitivity, low cost, large scale fabrication and easy minituarisation. One of the obstacles in their large-scale development, however, is the absence of a robust bioreceptor immobilization surface chemistry. In this work, we studied polydopamine film as an easy, cost-effective and one-step method to immobilise bioreceptors on the surface of silicon-based sensors. We show that the chemistry is highly stable in aqueous environments and is compatible with wide range of clinically relevant antibody-antigen pairs. With all the ease, the chemistry also offers high sensitivity (pg/mL) for IgG protein