Melanated Bacterial Cellulose via pH-Shifted Tyrosinase Development
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Solution Overview
Problem
Current methods for producing bacterial cellulose lack the ability to create self-pigmented and spatially restricted pigmented forms, as melanin formation is inhibited by low pH conditions during bacterial culture, limiting the material's applications in real-world contexts.
Innovation Solution
A two-step process involving the expression of tyrosinase in bacteria to produce melanated bacterial cellulose, where the cellulose pellicle is exposed to a development solution at a neutral pH with L-tyrosine, L-cysteine, and metal ions to facilitate melanin formation, and an optogenetic expression system for spatially restricted gene expression to create patterned pigmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bacterial culture is performed at low pH conditions to produce cellulose pellicle, then cellulose production is achieved, but melanin formation is inhibited
Solution Approach 1:
The patent divides the production process into two separate stages: first producing the cellulose pellicle at low pH, then treating it with neutral pH development solution containing tyrosine and metal ions to form melanin. This segmentation allows each process to occur under its optimal conditions without interference.
Solution Approach 2:
The cellulose pellicle is produced first as a preliminary step before melanin formation. The pellicle structure is prepared in advance under low pH conditions, then subsequently treated with development solution to enable melanin synthesis on the pre-formed cellulose matrix.
2Reliability
If a two-step process is used to produce melanated bacterial cellulose, then melanin formation is enabled, but production complexity increases
Solution Approach 1:
The patent combines two previously separate processes (cellulose production and melanin formation) into an integrated two-step workflow where the output of the first step becomes the substrate for the second step. This merging creates a cohesive production system despite the added step.
Solution Approach 2:
The patent utilizes parameter changes between steps: transitioning from low pH during cellulose production to neutral pH during melanin development, and adding different chemical components (tyrosine and metal ions) in the second step. These parameter changes enable the formation of melanin on the pre-formed cellulose pellicle.
3Shape
If uniform pigmentation is applied to bacterial cellulose, then aesthetic properties are improved, but functional versatility is reduced
Solution Approach 1:
The patent enables different regions of the cellulose pellicle to have different pigmentation properties by controlling melanin formation locally. This allows specific areas to be pigmented while others remain unpigmented or differently pigmented, providing spatial control over material properties.
Solution Approach 2:
The patent introduces dynamic control over pigmentation through the development process, where melanin formation can be adjusted in terms of timing, extent, and spatial distribution. This dynamic approach allows the same base cellulose material to be adapted for different applications by varying the pigmentation parameters.
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
Enables the production of melanated bacterial cellulose with enhanced properties and spatially controlled pigmentation, increasing its suitability for various applications by overcoming pH-related limitations and allowing for targeted material properties.
Implementation Method 1
expression of tyrosinase in bacteria to produce melanated bacterial cellulose
Implementation Method 2
exposed to a development solution at a neutral pH with L-tyrosine, L-cysteine, and metal ions to facilitate melanin formation
Implementation Method 3
an optogenetic expression system for spatially restricted gene expression to create patterned pigmentation
Implementation Method 4
BC is strong, with a single nanofiber having a high tensile strength of ̃1 GPa—similar to that of Kevlar. BC fibres are stiff under strain, with a Young's modulus of 114 GPa, similar to that of bronze. The high internal surface area and availability of hydroxyl groups within BC, means BC is highly hydrophilic, with a water retention of up 1000% its own weight.
Data Source
AI summary
The present invention relates to biomaterials, in particular bacterial cellulose and provides means to prepare pigmented cellulose at acidic pH 5.8, wherein cellulose pellicles comprising tyrosinase (EC 1.14.18.1) are melanated using a development solution at pH 6 to 8.5 and comprises tyrosine, cysteine and/or cystine. Further, the invention relates to means of preparing spatially restricted pigmented cellulose using an optogenetic expression system wherein two polymerase or transcription factor domains are split and each linked to a light-inducible dimerization domain. The invention provides corresponding methods and components.