Advanced Optical Nanosensors

Advanced optical nanosensors are sensors that convert the detectable interaction changes between molecules with analytes into analytically useful information based on light intensity. The radiation-sample interaction is measured for changes in certain optical properties in correlation with the analyte concentration. Also, a variety of optical principles can be applied to optical sensors (absorbance, reflection, luminescence, fluorescence), covering different regions of the spectrum (UV, visible, near-infrared (NIR)). This allows light intensity measurements plus other properties such as lifetime, refractive index, scattering, diffraction, and polarization. Additionally, the user often expects additional sensor characteristics, for instance, a sufficiently high signal-to-noise ratio, quick response time, low detection limit, high sensitivity, low cost, and the possibility of online and in-situ applications. This chapter aims to provide details of the principle and mechanism of specific optical nanosensors (viz., luminescent, surface plasmon resonance (SPR), and quantum dots), the preparation of certain advanced nanosensors (viz., nano-cellulose, silver nanoparticles, and carbon-based), and their current bionanotechnological applications. Optical nanosensors are an emerging technique for personalized health monitoring and could revolutionize how diseases are diagnosed and treated in the future. The use of optical nanosensors in environmental monitoring and food quality analysis is also prominent.