  The melanins are a ubiquitous class of pigments found throughout nature from
lower organisms to humans. It is one of the few biopolymers with fascinating
functions in biology, medicine, chemistry, physics and engineering due to its
relation to neurological diseases, skin disorders and melanoma, and, in the
last couple of decades, its applications in biocompatible and biodegradable
devices for organic electronic and bioelectronics. In this review, we present
the major advances in physicochemical, biochemical and photochemical properties
as well as some melanin-based technological application.
  Keywords: Melanin; physical-chemical properties; biochemistry; photochemistry
technological applications.
