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

This article gives a brief overview of the state of the art in optical methods for the detection of single molecules in biomedical applications. It has been shown that recording the 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: (1) visualization of biomolecules, toxins, virus particles, (2) determination of extremely low concentrations of analytes directly in a collected sample without using methods to increase the concentration of the analyte, (3) optical single-molecule sequencing of DNA molecules. The existing physical limitations of methods for optical detection and counting of single molecules and their implications for solving existing problems in biology, medicine and genetics will be discussed.