Acridine orange

Acridine orange is a nucleic acid selective fluorescent cationic dye useful for cell cycle determination. It is cell-permeable, and interacts with DNAand RNA by intercalation or electrostatic attractions respectively. When bound to DNA, it is very similar spectrally to fluorescein, with an excitationmaximum at 502 nm and an emission maximum at 525 nm (green). When it associates with RNA, the excitation maximum shifts to 460 nm (blue) and the emission maximum shifts to 650 nm (red). Acridine orange will also enter acidic compartments such as lysosomes and become protonated and sequestered. In these low pH conditions, the dye will emit orange light when excited by blue light. Thus, acridine orange can be used to identify engulfed apoptotic cells, because it will fluoresce upon engulfment. The dye is often used in epifluorescence microscopy.

Solução de Turk

Used in hematology, Turk's solution is a composed of a stain (Gentian violet) and 6% acetic acid.

The solution destroys red blood cells within a blood sample, and stains the nuclei of the white blood cells, making them easier to see and count.

Crystal violet or Gentian violet

Crystal violet or Gentian violet (also known as Methyl Violet 10B, hexamethyl pararosaniline chloride, or pyoctanin(e)) is a triarylmethane dye. The dye is used as a histological stain and in Gram’s method of classifying bacteria.

Crystal violet has antibacterial, antifungal, and anthelmintic properties and was formerly important as a topical antiseptic. The medical use of the dye has been largely superseded by more modern drugs, although it is still listed by the World Health Organization.

The name "gentian violet" was originally used for a mixture of methyl pararosaniline dyes (methyl violet) but is now often considered a synonym for crystal violet. The name refers to its colour, being like that of the petals of a gentian flower; it is not made from gentians or from violets.

Refringência ou Refração

(physics) The turning or bending of any wave, such as a light or sound wave, when it passes from one medium into another of different optical density.

Birefringência (physics) the splitting of a ray of light into two parallel rays of perpendicular polarization by passage through an optically anisotropic medium.