Effect of Melanomal Proteins on Sepia Melanin Assembly

Abstract

Keywords Downloaded by [Dalhousie University] at 08:36 11 October 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 Sepia melanin self-assembly; amyloid fibrils; cephalopod ink; scanning electron microscopy; Scanning transmission electron microscopy; Atomic force microscopy. ABSTRACT Melanins are phenol-based pigments with the potential for widespread applications including bioelectronics and tissue engineering. The concentration-dependent structural transition of sepia melanin in water is analyzed. This biopolymer at high concentration gives the well-known nanospheres, whereas sample dilution gives unforeseen nanofibres exhibiting the structural features of mature amyloid fibrils. We propose a mechanism of pigment self-assembly dependent on the interaction of residual melanosomal protein(s) with eumelanin heteropolymer. Our results contribute to understanding the peculiar physico-chemical properties of this ubiquitous pigment. Downloaded by [Dalhousie University] at 08:

From Extraction to Advanced Analytical Methods: The Challenges of Melanin Analysis

“…To become conductive, the melanin samples need to be coated first. For this purpose, a thin layer of gold [37,38,39] or gold/palladium alloy [40] is often used. Depending on the melanin source, the granule morphology and size range between 30–1000 nm and melanin granules are usually amorphous with irregular shape (Table 3).…”

“…The aqueous solutions of eumelanin (from Sepia officinalis ) were sonicated, centrifugated, lyophilized, and then re-dispersed in ultrapure water. The melanin aqueous suspension was deposited on a disc and the surface was further scanned [35,40,67,68].…”

Electro-responsive controlled drug delivery from melanin nanoparticles

“…Cuttlefish ink (Sepia officinalis) was purified by a method described elsewhere. [23] An ink suspension was obtained by dissolving 100 g of the commercial ink with 200 mL of ultrapure water. The suspension was centrifuged at 12,000 rpm for 15 min at 5 °C (5810R, Eppendorf, Germany) and the supernatants were discarded, while the obtained pellet was resuspended in ultrapure water.…”

The modulation of melanin‐like materials: methods, characterization and applications

“…Srisuk et al reported a concentration-dependent structural transition of sepia melanin in water, in which at high concentration sepia melanin gives the well-known nanospheres whereas dilution of the samples (0.1 mg L −1 and 10 μg L −1 ) gives nanofibers (minimum diameter ca 11 nm, several micrometers in length) exhibiting the structural features of mature amyloid fibrils. 69 In nature, birds use melanosomes to form organized structures for producing colors. Inspired by nature, melanin-like and PDA NPs have been investigated to produce structural colors.…”

“…Srisuk et al reported a concentration‐dependent structural transition of sepia melanin in water, in which at high concentration sepia melanin gives the well‐known nanospheres whereas dilution of the samples (0.1 mg L −1 and 10 µg L −1 ) gives nanofibers (minimum diameter ca 11 nm, several micrometers in length) exhibiting the structural features of mature amyloid fibrils …”