Viscoelastic Ink for Hydrogel Scaffold Fabrication
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Solution Overview
Problem
Current methods for fabricating three-dimensional structures with micron-scale features are limited by biocompatibility, speed, and complexity, particularly in creating hydrogel scaffolds for tissue engineering and photonic crystals, as they often require expensive equipment or result in structures with inconsistent defect control.
Innovation Solution
A viscoelastic ink system comprising a long chain polymer and a photopolymerizable moiety, along with a crosslinking agent and photoinitiator, is used for direct ink writing to create hydrogel scaffolds with precise microscale features, enabling the formation of biocompatible and mechanically robust structures through extrusion and photopolymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two-photon polymerization is used to create sub-micron features, then manufacturing precision is improved, but productivity deteriorates due to very slow fabrication rate
Solution Approach 1:
The patent replaces the slow two-photon polymerization process with a direct ink writing extrusion method that uses viscoelastic ink formulation and controlled extrusion mechanics, achieving both sub-micron precision and faster fabrication rates by using extrusion-based deposition followed by photopolymerization
Solution Approach 2:
The patent changes the material parameters by developing viscoelastic inks with specific rheological properties (shear-thinning behavior, elastic modulus, viscosity) that enable precise extrusion at high speeds while maintaining feature integrity, thus improving productivity without sacrificing manufacturing precision
2Device complexity
If conventional assembly techniques are used to fabricate microscale structures, then device complexity is reduced, but manufacturing precision deteriorates due to inability to control defect distribution
Solution Approach 1:
The patent applies preliminary action by formulating the ink with specific viscoelastic properties and crosslinking agents before extrusion, enabling the material to self-stabilize and maintain feature integrity during deposition, thus achieving precise defect control without complex assembly processes
Solution Approach 2:
The patent uses composite material formulation combining long-chain polymers, crosslinking agents, and photopolymerizable moieties to create viscoelastic inks that provide both structural integrity during extrusion and precise feature definition, eliminating the need for complex multi-step assembly techniques
3Object-affected harmful factors
If biocompatible materials are used for tissue engineering scaffolds, then object-affected harmful factors are reduced, but strength deteriorates due to material limitations
Solution Approach 1:
The patent uses composite material formulation combining biocompatible polymers (such as poly(ethylene glycol) diacrylate and gelatin methacryloyl) with crosslinking agents to create hydrogel inks that provide both excellent biocompatibility and enhanced mechanical strength, eliminating the traditional trade-off between these properties
Solution Approach 2:
The patent changes the material parameters by controlling crosslinking density, polymer concentration, and molecular weight to tune the mechanical properties of biocompatible hydrogels, achieving high strength while maintaining cytocompatibility for tissue engineering applications
4Ease of operation
If simple extrusion is used to deposit hydrogel filaments, then ease of operation is improved, but manufacturing precision deteriorates due to feature deformation
Solution Approach 1:
The patent changes the rheological parameters of the ink by formulating viscoelastic materials with shear-thinning behavior and appropriate elastic modulus, enabling simple extrusion operation while maintaining precise feature shape control through the material's inherent viscoelastic properties during and after deposition
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 creation of hydrogel scaffolds with tailored microscale features, demonstrating excellent cytocompatibility and mechanical properties, suitable for tissue engineering and other applications, such as tunable optical sensors and stimuli-responsive materials.
Implementation Method 1
The ink may also include a crosslinking agent, a photoinitiator, and water
Implementation Method 2
The long chain polymer is present at a concentration above a critical overap concentration c* of the long chain polymer in the ink
Implementation Method 3
The one or more hydrogel filaments have a pre-polymerized structure and a post-polymerized structure
Data Source
AI summary
A viscoelastic ink for direct writing of hydrogel structures includes a long chain polymer and a photopolymerizable moiety, which may be a photopolymerizable monomer or a photopolymerizable group attached to the long chain polymer. The ink may also include a crosslinking agent, a photoinitiator, and water. The long chain polymer is present at a concentration greater than a critical overlap concentration c* of the long chain polymer in the ink.