Deep‐Ultraviolet Biomolecular Imaging and Analysis

Deep-ultraviolet light, 200-300 nm in wavelength, interacts with nucleic acids and proteins strongly compared to visible and infrared light. In this article, the interaction between deep-ultraviolet photons and biomolecules is discussed. Especially, the absorption and autofluorescence of biomolecules by the deep-ultraviolet excitation are examined. Applications of deep-ultraviolet absorption and autofluorescence to label-free biomolecular imaging and analysis of cells and tissues are shown. Resonant Raman scattering at nucleotide bases and aromatic amino acids as another important topic of deep-ultraviolet photonics is reviewed in biomolecular imaging and analysis. The discussion extends to the recent progress in the development of deep-ultraviolet microscopes as well as a variety of deep-ultraviolet optical devices such as light sources, detectors, and objectives. The issue of photodamage due to deep-ultraviolet irradiation on cells and tissues is also discussed. It has been recently suppressed with use of lanthanide ions. The experimental results of the photodamage suppression are shown. For surface-enhanced resonant Raman scattering, autofluorescence enhancement, and tip-enhanced resonant Raman scattering microscopy, plasmonic materials applicable in the deep-ultraviolet range are discussed.