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Fabrication of Multi-Material Structures using Micro-Stereolithography

Multi-Material Carousel
Multi-Material Scaffold containing modified Pluronic L-31 and poly(propylene glycol) diacrylate (PPGDA)

Project Overview

Design and build a machine component that will allow a presently existing mask projection microStereolithography machine to fabricate parts using two or more materials.

Key Results:
Fabrication of multi-material parts with micron-scale feature sizes that can be used as tissue scaffolds and microfluidic devices. Future work will include exploring photocuring interactions between dissimilar photopolymers as well as cell response to tissue scaffolds made from more than one material.

Micro-stereolithography is a promising technique for producing ordered, customizable structures with micron-scale features. However, conventional fabrication techniques are unable to selectively place material in three-dimensional space and can often only produce structures made with a single material. Additive Manufacturing techniques that are able to produce multi-material structures have insufficient resolution and are unable to fabricate structures with micron-sized features. 

This severely limits their application, preventing the production of complex structures necessitated by such fields as tissue scaffolds and microfluidics. Micro-stereolithography is uniquely capable of producing such structures because the resolution and achievable feature size are limited primarily by the system’s optics. Additionally, the technique affords the possibility of material change-out during part fabrication.

This work is focused on producing complex structures via the addition of a specialized multi-material system to the existing Micro-stereolithography machine. A motorized carousel holds multiple vats of material as shown in Fig. 1. An Arduino microcontroller and motor rotate the carousel such that the vat filled with the required material is beneath the build stage for each layer. A cleaning step is included between material change-out to avoid contamination between vats. A preliminary scaffold made from modified Pluronic L-31 and poly(propylene glycol) diacrylate (PPGDA) scaffold is shown in Fig. 2. Machine modifications are planned to improve feature size, layer thickness control, and cleaning.

Related Publications

N. Chartrain, M. Price, A. Schultz, T. Long, C. Williams, A. Whittington, “Fabrication of Multi-Material Tissue Scaffolds via Additive Manufacturing,” poster presentation at the Society for Biomaterials 2015 Annual Meeting & Exposition, 15-18 April 2015, Charlotte, NC.

Research Lead

Nicholas A. Chartrain