Sacrificial Polymer Template for Hydrogel Microchannels
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Solution Overview
Problem
Current methods for creating three-dimensional structures for cell growth, such as lumen structures, face challenges in generating biologically relevant environments with appropriately sized lumens and meaningful organization, particularly in using sacrificial templates that are not easily seeded with cells and lack mechanical integrity.
Innovation Solution
A method using a PsecBuOx-stat-PAOx co-polymer as a sacrificial template, which is embedded in a hydrogel and can be easily removed by lowering the temperature, allowing for cell seeding and maintaining mechanical integrity, with the polymer being biocompatible in both solid and dissolved states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sugar is used as a sacrificial template, then the template can be easily removed, but the template is soluble, cannot be pre-seeded with cells, and is cytotoxic
Solution Approach 1:
The patent changes the chemical composition parameters of the sacrificial template from sugar to a copolymer with specific hydrophobic and hydrophilic segments. The hydrophobic segments provide cytocompatibility while the hydrophilic segments enable water solubility for easy removal, thus resolving the contradiction between ease of removal and cytotoxicity
Solution Approach 2:
The patent uses a copolymer composed of hydrophobic and hydrophilic segments as a composite material. The hydrophobic segments (e.g., polyether) provide biocompatibility and cell adhesion properties, while the hydrophilic segments (e.g., polyoxazoline) enable water solubility for template removal, resolving the contradiction between ease of removal and cytotoxicity
2Strength
If pNIPAM polymer is used as a sacrificial template, then the template retains mechanical integrity above LCST, but the temperature transition range is narrow and it is too hydrophilic to be pre-seeded with cells
Solution Approach 1:
The patent applies local quality by creating a copolymer with distinct hydrophobic and hydrophilic segments. The hydrophobic segments provide cell-adhesive properties enabling pre-seeding, while the hydrophilic segments maintain water solubility for template removal, resolving the contradiction between mechanical integrity and hydrophilicity
Solution Approach 2:
The patent uses a copolymer composite material combining hydrophobic and hydrophilic segments. The hydrophobic segments provide cytocompatibility and cell adhesion for pre-seeding, while the hydrophilic segments enable water solubility, resolving the contradiction between mechanical integrity and hydrophilicity
3Shape
If gel-in-gel constructions are used to create microchannels, then oriented arrays can be formed, but the structures are large and bulky and rely on cell organization
Solution Approach 1:
The patent extracts the microchannel-forming function from cell-dependent gel-in-gel constructions and transfers it to a sacrificial template system. The template provides pre-defined microchannel geometries that are replicated in the hydrogel, eliminating the need for large bulky structures and cell organization
Solution Approach 2:
The patent applies preliminary action by pre-forming the microchannel template structure before hydrogel casting. The sacrificial template is created with the desired microchannel geometry, embedded in the hydrogel, and then removed to leave precisely defined channels, eliminating the need for cell-dependent organization
4Shape
If fugitive inks are used to create microchannels, then microchannel structures can be formed, but the constructions are mechanically weak
Solution Approach 1:
The patent uses a sacrificial template that is intentionally designed to be temporary and removable. The template provides mechanical support during structure formation, then is easily removed by dissolution, leaving the final microchannel structure. This resolves the contradiction by using a disposable strong template rather than creating a permanently weak structure
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 enables the creation of stable three-dimensional structures for cell growth with controlled cell seeding and dissolution, overcoming issues of mechanical integrity and biocompatibility, and allows for the formation of microchannel networks lined with cells.
Implementation Method 1
One of the mechanisms for creating a sacrificial template is the use of polymers that have a thermally induced solubility. These polymers have a so-called Lower Critical Solubility Temperature (LCST). Above this temperature, the polymers are hydrophobic and retain their mechanical integrity allowing the structure to be embedded within a hydrogel. After cooling to a temperature below the LCST, the polymer will transition to its hydrophilic state, allowing it to become water soluble.
Data Source
AI summary
The present invention relates to a method for creating a three- dimensional structure for cell growth by creating a template of a polymer, applying a hydrogel support onto the template and removing the template. The present invention further provides a device for cell growth comprising a polymer template embedded in a hydrogel.