Issue 8, 2024

Enlisting electrochemistry to reveal melanin's redox-related properties

Abstract

Melanin has been surprisingly difficult to characterize using either bottom-up studies focused on molecular structure or top-down studies focused on functional properties. We have been developing electrochemical methods to understand the redox-activities of melanin. These studies show that melanins from various sources: (i) are reversibly redox-active; (ii) have redox potentials in the mid-physiological range; and (iii) react with a broad range of electron-donors (i.e., reductants) and acceptors (i.e., oxidants). Spectroelectrochemically-based operando methods have shown that when melanin is exchanging electrons, it also undergoes changes in its redox state. The observation that melanin can exist in two (or possibly more) oxidized or reduced states helps to explain some of its context-dependent behaviors. For instance, when melanin is in a reduced state, it has donate-able electrons that can quench an oxidative radical or partially-reduce O2 to generate reactive oxygen species (ROS). Further, melanin can promote redox-cycling when it is located in metabolically-active contexts that are characterized by steep O2-gradients because short diffusion distances separate aerobic from anaerobic conditions. We suggest that future studies may enable a fuller understanding of how melanin's redox activities contribute to its observed electrical conductivities (ionic and/or electrical), and if melanin's redox-capacitor properties confer a biological benefit (e.g., for energy harvesting).

Graphical abstract: Enlisting electrochemistry to reveal melanin's redox-related properties

Article information

Article type
Review Article
Submitted
21 Dec. 2023
Accepted
05 Marts 2024
First published
05 Marts 2024
This article is Open Access
Creative Commons BY-NC license

Mater. Adv., 2024,5, 3082-3093

Enlisting electrochemistry to reveal melanin's redox-related properties

E. Kim, Z. Wang, J. W. Phua, W. E. Bentley, E. Dadachova, A. Napolitano and G. F. Payne, Mater. Adv., 2024, 5, 3082 DOI: 10.1039/D3MA01161E

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements