Fluorescence microscopy

A fluorescence microscopy system is an optical method based on optical fluorescence instead of, or in addition to, scattering, reflection, and attenuation or absorption, to characterize the properties of organic or inorganic substances.

ZNI utilizes fluorescence to generate an image, whether it is a more simple set up like an epifluorescence microscope or a more complicated design such as a confocal microscope, which exploits optical sectioning to get better resolution of the fluorescence image.

When the specimen is illuminated with light of a specific wavelength (or wavelengths), the fluorophores absorb light energy resulting in generation of fluorescence signals at longer wavelengths (i.e., of a different color than the absorbed light). The illumination light is separated from the much weaker emitted fluorescence through the use of an optical filter. Multispectral fluorescence images can be achieved by ZNI with multiwavelength lasers and detection units. 

ZNI is operated at longer wavelengths in the NIR-II, which has many advantages, such as deeper tissue penetration, high resolution and contrast in images compared to visible or NIR-I light. ZNI has relatively low light scattering and absorption by biomolecules with deep tissue penetration compared to visible light (400–650 nm), which is allowing for deeper tissue penetration, and high resolution and contrast in images. ZNI has low autofluorescence of biologic tissues, which can produce a high signal-to-background ratio (SBR) in living organisms. ZNI can enable high sensitivity and resolution imaging in the NIR-I region