Nanomaterials have received increasing attention due to their unique physical and chemical properties such as high surface-to-volume ratio, high electrical conductivity, chemical stability/durability, and high mechanical strength suitable for applications in many fields, such as biotechnology, optics, electronics, and catalysis. In this review, a survey of the application of different nanomaterials and nanocomposites, with the focus on sensing platforms for detection of phenolic antioxidants and serotonin is presented.