Fluorescence Lifetime Imaging Microscopy Analysis of Isolated Melanosomes

TL;DR

This study employs Fluorescence Lifetime Imaging Microscopy (FLIM) to analyze the fluorescent properties and photoinduced structural changes of melanin in isolated melanosomes over time.

Contribution

First application of FLIM to study melanosomes, revealing dynamic fluorescence lifetime changes and structural alterations of melanin upon irradiation.

Findings

Identified a short-lived fluorescence component in melanosomes.

Observed significant lifetime changes indicating photoinduced melanin modifications.

Detected structural changes occurring within minutes to an hour of irradiation.

Abstract

Melanosomes are organelles found in a wide variety of tissues throughout the animal kingdom. They contain a variety of biological molecules, but the dominant constituent is the pigment melanin, and many functions ascribed to melanosomes, such as photoprotection, are uniquely enabled by the chemical properties and structures of the melanins they contain. In this report, we used, for the first time, Fluorescence Lifetime Imaging Microscopy (FLIM) to examine fluorescent properties of pigments in melanosomes and evaluate their time evolution upon extended laser irradiation. We discovered a relatively short-lived component in fluorescence emission and revealed significant changes in lifetimes upon irradiation indicating structural photoinduced changes to melanin occurring on a time scale of minutes, with observations extending up to one hour.