Optical methods for detection of single biomolecules: visualization, sensorics, sequencing of DNA molecules

A brief overview of the state of the art in optical methods for detecting a single molecule in biomedical applications is presented. It is shown that the registration of fluorescence of single dye molecules covalently bound to antibodies (biomolecules), together with the use of modern nanophotonics methods, can be used to solve various problems in biology and medicine: visualization of biomolecules, toxins, and virus particles; determination of extremely low concentrations of analytes directly in a sample without using methods for increasing the analyte concentration; and optical single-molecule sequencing of DNA molecules. The existing physical limitations of the methods of optical detection and counting of single molecules and their impact on solving existing problems in biology, medicine, and genetics are discussed.