(INVITED)Surface enhanced infrared absorption spectroscopy using plasmonic nanostructures: Alternative ultrasensitive on-chip biosensor technique

The increasing demand for more reliable and cost effective biosensors has steered development of various novel biosensor platforms. Sensors based on optical techniques have attracted much attention because of their advantages, such as immune to electromagnetic interference, multiplex and cost effective. Surface enhanced infrared absorption (SEIRA) is a powerful vibrational label-free analytical technique that has benefited from collective excitation of surface plasmon to enhance vibrational signals of thin molecular layers. Owing to surface plasmon phenomenon to enhanced vibrational signal, SEIRA has attracted much research attention t as an alternate promising biosensor platforms and in recent years, continuous SEIRA sensing platforms are emerging. In this brief review, we outline the principle of SEIRA, in particular, theoretical models that give insight into the light interactions with plasmonic nanostructures and the coupling between nanostructures and vibrational molecules. With this, commonly used active SEIRA substrates and their optimization methods are discussed, ranging from materials, geometrical design and commonly used fabrication methods. Also discussed are advancements in analytical applications of SEIRA and brief future perspectives on SEIRA sensing platform.