DAPI (4′,6-diamidino-2-phenylindole) is a blue-fluorescent DNA stain  that binds strongly to A-T rich regions in DNA. As DAPI can pass through an intact cell membrane, it is commonly used as a nuclear counterstain in fluorescence microscopy, flow cytometry, and chromosome staining.

Optolong Optics Co.,ltd is the brand owner of optolong who is a manufacturer of astronomy filters, fluorescence filters. We also offer other interference filters like UV filters, visible filters and Near inferred filters, beam splitter, anti-reflection coating and optical mirrors as a OEM service.

Located in Kunming city in China which is one of the four optics center and the coating experience of 18 years (since 1999) enable us to design and produce the filters with most sophisticated spectrum.

We are glad to declare that Optolong has been become the first and only non-replaceable brand for astronomical filters in China. Optolong brand is also known as the comparable filters with international brand by distributor client around the world.