Microstereolithography Post-Curing for Cytocompatible 3D Structures
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Solution Overview
Problem
Conventional microstereolithography techniques produce cytotoxic three-dimensional structures due to residual monomers and photopolymerization initiators, limiting their application in direct contact with living cells or organisms.
Innovation Solution
A post-curing process involving heating microstereolithographic structures to their glass transition temperature (175-200°C) for 6-24 hours after UV-curing to detoxify and render them cytocompatible, using materials like acrylate, epoxy, acrylate-epoxy complex, and oxetane resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If commercial photocurable resins are used for microstereolithography, then manufacturing precision and structural stability are improved, but cytotoxicity increases due to residual monomers and photopolymerization initiators
Solution Approach 1:
The patent applies a post-curing heat treatment process (heating to glass transition temperature of 175-200°C for 6-24 hours) after microstereolithography fabrication. This preliminary action removes residual monomers and photopolymerization initiators before the structure contacts living cells, thereby eliminating cytotoxicity while preserving the precisely fabricated three-dimensional structure
Solution Approach 2:
The patent changes the physical and chemical parameters of the photocurable resin by heating it to its glass transition temperature range (175-200°C). This parameter change transforms the resin from a cytotoxic state with residual monomers to a cytocompatible state where residual monomers are removed through controlled heating, while maintaining the structural integrity achieved through microstereolithography
2Object-affected harmful factors
If biodegradable polymers are synthesized for cytocompatibility, then cytotoxicity is reduced, but device strength and structural stability deteriorate
Solution Approach 1:
The patent extracts and removes the harmful components (residual monomers and photopolymerization initiators) from the commercial photocurable resin through post-curing heat treatment. This extraction process eliminates cytotoxicity while retaining the strong, non-biodegradable polymer matrix that provides the necessary device strength and structural stability
Solution Approach 2:
The patent converts the previously harmful residual monomers and photopolymerization initiators into beneficial removed components through the post-curing process. By heating to glass transition temperature, these harmful substances are eliminated, transforming the material from cytotoxic to cytocompatible while maintaining the beneficial mechanical properties of the original commercial resin
3Object-affected harmful factors
If hydrogels are used for cell culture compatibility, then cytocompatibility is improved, but mechanical strength and processability deteriorate
Solution Approach 1:
The patent enables the commercial photocurable resin to serve itself by applying a post-curing heat treatment that removes residual monomers and photopolymerization initiators. This self-service process makes the originally cytotoxic commercial resin cytocompatible without requiring external hydrogel materials, thereby maintaining the resin's inherent mechanical strength and microstereolithography processability
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 process achieves cytocompatibility comparable to commercial cell culture dishes, enabling the use of microstereolithographically fabricated structures for direct cell contact and expanding their application in biomedical devices.
Implementation Method 1
Microstereolithography is a precision machining technology to fabricate structures of an arbitrary shape by exposing photocurable resins to laser light
Implementation Method 2
heating microstereolithographic structures to their glass transition temperature (175-200°C) for 6-24 hours after UV-curing to detoxify and render them cytocompatible
Data Source
AI summary
Three-dimensional microstereolithographic objects fabricated by microstereolithography are exposed to UV light for one hour to accelerate hardening. The structures are then heated at 175° C. or above for at least 6 hours. The heating temperature may exceed the glass transition temperature, which is the index of thermal softening temperature of materials. The present invention relates to three-dimensional microstructures formed by microstereolithography. Deformation due to a structure's own weight, which generally poses a problem in heat treatment, is reduced with microstructures due to the size effect. As a result, the dimensions of the three-dimensional structure fabricated by the present invention remain almost unchanged before and after the heat treatment.