Multiple Material Microstereolithography
We have previously described the development of a µSL system using a Digital Micromirror Device (DMDTM) for dynamic pattern generation and an ultraviolet (UV) lamp filtered at 365 nm for crosslinking the photoreactive polymer solution. The µSL system was designed with x-y resolution of ~2 µm and a vertical (z) resolution of ~1 µm (with practical limitations on vertical resolution of ~30 µm resulting from the current laboratory setup). This µSL system is capable of producing real three-dimensional (3D) microstructures, which can be used in micro-fluidics, tissue engineering, and various functional micro-systems. As has been explored and described in µSL, many benefits will potentially be derived from producing multiple material microstructures in µSL. One particular application area of interest is in producing multiple material micro-scaffolds for tissue engineering. In this work, a method for multiple material µSL fabrication was developed using a syringe pump system to add material to a small, removable vat designed for the µSL system. Multiple material fabrication was accomplished by manually removing the vat and draining the current material, rinsing the vat, placing the vat back into the system, and dispensing a prescribed volume in the vat using the syringe pump. Layer thicknesses less than ~30 µm were achieved using this process. To demonstrate this system, several multiple material microstructures were produced, and we believe multi-material µSL represents a promising technology for producing functional microstructures with composite materials.