A surface enhanced Raman spectroscopy (SERS) sensor, system and method employ nanorods and independent nanoparticles that interact. The sensor includes at least two spaced apart nanorods attached at first ends to a substrate and an independent nanoparticle. Second ends of the nanorods are movable into close proximity to one another and include a Raman active surface. The nanoparticle has a functionalized surface that includes a Raman signal generator. An interaction between the nanoparticle and the nanorod second ends in close proximity is detectable. The system includes the SERS sensor, an illumination source and a Raman signal detector. The method includes illuminating the interaction of the nanoparticle and the nanorods with an analyte, and detecting an effect on a Raman signal caused by the analyte.