Different methods for single molecule detection

Abstract The molecule is the smallest unit that can exist independently and maintain the physical and chemical properties of the substance, so single molecule detection is a critical technology in biology, chemistry, and other disciplines. Today, different instruments and methods for single-molecule detection exist. Each single molecule detection method’s principle, operation, and application scope differ. Systematic analysis and summary are needed. This research will outline the principles and recent achievements of several single-molecule detection methods, from microscopes to spectrometers and biosensors. The development of atomic force microscopy (AFM) is mainly introduced in microscopy. First, the fundamentals of AFM will be introduced, followed by high-speed atomic AFM (Hs-AFM) and its integrated green laser irradiation of single molecules for dynamics, Later, we will introduce the recently developed Localization AFM (LAFM) with higher resolution and the Single-molecule localization microscopy (SMLM) with similar principle. Raman spectroscopy and Raman imaging are mainly introduced in spectroscopy. In the last aspect of biosensors, the principle and development of nanopore and enzyme-linked immunosorbent assay (ELISA) are mainly introduced.