Nanomaterial-based single-molecule optical immunosensors for supersensitive detection

Unlike bulk materials, nanomaterials have unique properties that make them suitable for biosensor applications. Nanomaterial-based biosensors have a series of advantages that can help realize high throughput and ultrasensitive detection. In recent years, considerable research has been performed on integrating nanomaterials and single-molecule immunosensors. This review provides an overview on the various types of nanomaterials used for signal amplification in single-molecule immunosensors, with a focus on the development of optics-based immunosensors using precious plasmonic noble metals (e.g., gold, silver), magnetic beads, quantum dots, upconversion nanoparticles, and nanocomposites. In particular, an approach is presented of using single-molecule immunosensors to detect and quantify biomolecular interactions (e.g., antibody–antigen). Integrating supersensitive bio-devices and nanomaterials is expected to offer significant advantages for trace element diagnosis and early diagnosis.