Fluorescent quantification of melanin

Abstract

Melanin quantification is reportedly performed by absorption spectroscopy, commonly at 405 nm. Here, we propose the implementation of fluorescence spectroscopy for melanin assessment. In a typical in vitro assay to assess melanin production in response to an external stimulus, absorption spectroscopy clearly overvalues melanin content. This method is also incapable of distinguishing non-melanotic/amelanotic control cells from those that are actually capable of performing melanogenesis. Therefore, fluorescence spectroscopy is the best method for melanin quantification as it proved to be highly specific and accurate, detecting even small variations in the synthesis of melanin. This method can also be applied to the quantification of melanin in more complex biological matrices like zebrafish embryos and human hair.This work was supported by the Portuguese Foundation for Science and Technology (FCT) through the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145- FEDER-006684) and BioTecNorte Operation (NORTE-01-0145- FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. The authors would like to thank to the hair donor volunteers and to Marisa Passos, Ana Sofia Teixeira, and In^es Pinto for technical assistance regarding the collection of zebrafish embryos. The author Teresa Matam a would also like to acknowledge her postdoctoral fellowship funded by FCT (SFRH/BPD/ 102153/2014)