Improving the Resolution of 3D-Printed Molds for Microfluidics by Iterative Casting-Shrinkage Cycles.
Miao SunYanbo XieJihong ZhuJun LiJan C T EijkelPublished in: Analytical chemistry (2017)
Breaking through technical barriers and cost reduction are critical issues for the development of microfluidic devices, and both rely greatly on the innovation of fabrication techniques and use of new materials. The application of 3D printing definitely accelerated the prototyping of microfluidic chips by its versatility and functionality. However, the resolution of existing 3D printing techniques is still far below that of lithography, which makes it difficult to work on the scale of single cells and near impossible for single molecule work. In this paper, we present a facile way to increase the resolution of 3D printed microstructures to minimally 4 μm by casting-shrinkage cycles of a polyurethane (PU) polymer. A water-PU liquid mixture poured on a 3D printed template quickly solidifies replicating the structures, which then isometrically shrink to half its size after solvent evaporation, downscaling the replicated structures. By repeating the casting-shrinkage cycles, we could downscale the (sub)millimeter structures of 3D printed structures on demand, until the working limit posed by the polymer properties, which we demonstrate by fabricating a micromixer. Moreover, we can even fabricate microfluidic chips from millimeter-scale manually assembled templates, fully independent of any micromachining facilities, significantly reducing the technical barriers and costs, thus opening up the microfluidics field to low-resource areas.
Keyphrases
- single molecule
- high resolution
- high throughput
- single cell
- circulating tumor cells
- atomic force microscopy
- living cells
- induced apoptosis
- ionic liquid
- label free
- highly efficient
- cell death
- magnetic resonance
- oxidative stress
- endoplasmic reticulum stress
- gold nanoparticles
- contrast enhanced
- low cost
- solid phase extraction