The paper reviews recent developments in the design of optical nanosensors based on localized surface plasmon resonance (LSPR) spectroscopy. The interest of using multilayered LSPR interfaces with dielectric overcoatings will be discussed in the context of biological and chemical sensing. The first section addresses the formation of the multilayered LSPR interfaces. A special focus will be on the influence of the refractive index and the thickness of different dielectric materials on the sensitivity of the LSPR nanosensor. The second part details the use of different surface functionalization schemes, which have been employed for the covalent linking of organic and biological molecules. Two different examples for the detection of hybridization events using LSPR spectroscopy will be discussed. Finally, the first steps towards the creation of active plasmonic interfaces will be shown. They are based on the covalent linking of actuators such as the p -electron deficient tetracationic cyclophane cylcobis(paraquat- p -phenylene) (CBPQT4+) onto multilayered LSPR sensors and the detection of the change in the optical signal when host-guest complexes are formed.