Nano-sized Melanin Particles via Dopamine Oxidation Control

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Solution Overview

Problem

Natural melanins are insoluble in solvents like water, and synthetic melanins have limitations due to irregular morphologies, long synthesis times, and poor solubility and dispersibility, making it difficult to produce nano-sized particles that are dispersible in solvents.

Innovation Solution

A method involving acid-base neutralization of a dopamine-containing aqueous solution with a base, controlling the molar ratio and reaction conditions to produce nano-sized melanin particles with precise size and shape control, enabling excellent dispersibility in water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If melanins are obtained from natural sources or by conventional artificial synthesis, then melanin production is achieved, but the melanins are insoluble in solvents and have poor dispersibility

Engineering Contradiction:
Improvemelanin productionVSAvoidsolubility and dispersibility in solvent
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent applies parameter changes by controlling the pH of the reaction medium and the oxidation conditions to produce melanin particles with nano-scale dimensions. By adjusting these parameters, the melanin particles achieve excellent dispersibility in water and other solvents while maintaining high production efficiency. The controlled pH environment during synthesis is key to achieving both high yield and good solubility.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If conventional artificial synthesis methods are used, then melanin is produced, but the synthesis time is long and the morphology is irregular

Engineering Contradiction:
Improvemelanin productionVSAvoidsynthesis time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent employs strong oxidants such as hydrogen peroxide, sodium periodate, or potassium permanganate to accelerate the oxidation of dopamine or DOPA. This accelerated oxidation process significantly reduces the synthesis time from several hours or days to just minutes or hours, while simultaneously producing melanin particles with uniform nano-scale morphology and size distribution.

Inventive Principle:
Principle #38Strong oxidants (Accelerated oxidation)

3Manufacturing precision

If conventional synthesis methods are used, then melanin is produced, but nano-sized particles with good dispersibility cannot be obtained

Engineering Contradiction:
Improveparticle size controlVSAvoiddispersibility in solvent
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent utilizes parameter changes by precisely controlling pH, oxidation potential, and reaction temperature to generate melanin particles with consistent nano-scale dimensions. These controlled parameters ensure that the particles remain small enough to disperse well in solvents while maintaining structural integrity and uniformity, achieving both manufacturing precision and ease of operation.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If natural melanins are used, then melanin is obtained, but the production amount is not constant and standardized procedures are lacking

Engineering Contradiction:
Improvemelanin production amountVSAvoidproduction consistency
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent employs a self-service approach where the synthetic melanin production system is fully controllable and repeatable. By using well-defined chemical reagents (dopamine or DOPA) and controlled oxidation conditions, the system produces melanin with consistent quantity and quality without relying on biological variability. This standardized chemical synthesis procedure ensures constant production amounts and high manufacturing precision across different batches.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method allows for the production of nano-sized melanin particles with excellent dispersibility in water, suitable for various applications, including biomedical fields, metal scavenging, and photoprotective materials.

Implementation Method 1

The present inventors polymerized melanins by oxidation of dopamine

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

polymerized melanins by oxidation of dopamine resulting from the chemical reaction of a dopamine·HCl

Methodology Applied
Scientific EffectPolymerization:

Data Source

PatentEP2492302B1Nano-sized melanin particles and method of producing same
Publication Date: 2022.11.16 MELANIS CO LTD
  • EP2492302B1 patent drawingFigure 1~2
  • EP2492302B1 patent drawingFigure 3~4
  • EP2492302B1 patent drawingFigure 5~6

AI summary

The present invention provides nano-sized particles of melanin, and the method for formation of the melanin particles comprises the following steps: adding a base to a dopamine·H+X--containing solution (wherein H+X- is an acid) and allowing an acid-base neutralization reaction; and forming nano-sized particles of melanin by controlling the addition of nucleic dopamine·H+X- (a) to base (b) at a ratio of a:b=1:0.1-1, and allow concurrent or consecutive formation of melanin by oxidation curing of the dopamine in air (polymerization). The manufacturing method according to the present invention can produce nano-sized melanin particles in a short period of time. Furthermore, the nano-sized melanin particles made according to the present invention are distinctive from conventional solvents containing dispersions of natural melanin and synthetic melanin, and have excellent application in various fields.