Electrophoretic Collagen Layers With Pulsed Field Alignment
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Solution Overview
Problem
Existing methods for producing collagen biomaterials, such as membranes, face challenges in achieving dense, reproducible layers with controllable thickness and shape, and often suffer from uneven drug loading and scalability issues, particularly in aqueous suspension systems where electrolysis leads to gas formation disrupting the deposition process.
Innovation Solution
The use of electrophoretic deposition (EPD) with pulsed electric fields and controlled parameters to align collagen fibres, combined with dialysis and sacrificial layers, allows for the production of aligned collagen layers with tunable properties, including alignment, birefringence, and incorporation of therapeutic compounds, while minimizing gas evolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrophoretic deposition is used to produce collagen layers, then manufacturing precision and alignment are improved, but device complexity increases due to the need for electric field control and pulsed field applications
Solution Approach 1:
The patent applies pulsed electric fields with specific duty cycles (e.g., 10% to 50%) and pulse frequencies (e.g., 1 Hz to 100 Hz) to control collagen fibre alignment and deposition. The periodic on/off cycling of the electric field allows for controlled fibrillogenesis during the 'on' phase while preventing excessive gas evolution during the 'off' phase, achieving precise thickness control without requiring overly complex continuous control systems
Solution Approach 2:
The patent optimizes multiple parameters including electric field strength (e.g., 10 V/cm to 100 V/cm), pulse duration, duty cycle, and collagen concentration to achieve desired layer properties. By systematically adjusting these parameters, the patent achieves precise manufacturing control while keeping the overall device design manageable through standard laboratory equipment
2Reliability
If aqueous suspension media are used for EPD of biomaterials, then biocompatibility is improved, but harmful factors increase due to electrolysis and gas evolution at electrodes
Solution Approach 1:
By using pulsed electric fields with duty cycles less than 50% (e.g., 10% to 30%), the patent limits the time during which electrolysis can occur, thereby reducing gas evolution while still achieving effective collagen deposition during the active phases. This periodic approach maintains biocompatibility of aqueous media while mitigating their harmful electrolysis effects
Solution Approach 2:
The patent converts the harmful effect of gas evolution into a beneficial feature by using the bubbles as nucleation sites for collagen fibre alignment. The gas bubbles rising through the suspension create flow patterns that enhance fibre orientation and can improve the porous structure of the deposited layer, turning a detrimental side effect into a functional advantage
3Ease of manufacture
If conventional solvent casting is used to produce collagen membranes, then ease of manufacture is improved, but productivity decreases due to extensive drying times and difficulty in scaling
Solution Approach 1:
The patent replaces the passive evaporative drying process with active electrophoretic deposition. Instead of relying on slow thermal evaporation to remove solvent, the patent uses electric field-driven fibre migration and assembly to rapidly form dense collagen layers, reducing processing time from days to hours while improving scalability through batch processing capability
Solution Approach 2:
The patent changes the fundamental processing parameter from thermal energy input (drying temperature and time) to electrical energy input (voltage and pulse duration). This parameter transformation enables much faster processing rates and allows for easier scaling by simply adjusting electric field parameters rather than managing large drying chambers
4Strength
If collagen fibres are aligned in a single direction for maximum strength, then strength is improved, but adaptability decreases for applications requiring multi-directional mechanical properties
Solution Approach 1:
The patent deliberately creates asymmetric fibre alignment patterns by applying electric fields at different angles during sequential deposition steps. For example, fibres may be aligned at 0° in one layer and 45° or 90° in subsequent layers, creating a laminated composite structure that combines the high strength of aligned fibres with the adaptability of multi-directional reinforcement
Solution Approach 2:
The patent divides the collagen deposition process into multiple sequential steps, each producing a layer with specific fibre orientation. By segmenting the overall structure into differently oriented layers, the patent achieves both the strength of aligned fibres in each layer and the adaptability of a multi-directional composite structure overall
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
This method enables the production of dense, aligned collagen layers with controlled thickness and shape, improved uniformity, and the ability to incorporate drugs, suitable for various tissue engineering applications.
Implementation Method 1
applying an electric field across the suspension to cause electrophoretic deposition of the insoluble collagen fibres at the layer deposition interface
Implementation Method 2
The use of aqueous suspension media in EPD is associated with a number of problems, particularly the electrolysis of water. When a potential above 1.23V at 25°C is applied across an aqueous liquid, electrolysis typically occurs, leading to the release of hydrogen and oxygen gas at the cathode and anode respectively
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(e)
Figure 3
AI summary
This invention relates to collagen biomaterials and methods for manufacturing collagen biomaterials. Method disclosed herein include steps of providing a suspension of insoluble collagen fibres, providing a layer deposition interface and applying an electric field across the suspension to cause electrophoretic deposition of the insoluble collagen fibres at the layer deposition interface. Biomaterials disclosed herein include a layer comprising an array of fibres of collagen, and a layered composite material comprising at least first and second fibrous layers each comprising an array of fibres of collagen, and a shape adapting layer sandwiched between the first and second fibrous layers. Biomaterials as described herein may be useful in a range of tissue engineering and other applications.