Multi-material Gradient Printing Using Meniscus-enabled Projection Stereolithography (MAPS)

Light-based additive manufacturing methods have been widely used to print high-resolution 3D structures for applications in tissue engineering, soft robotics, photonics, and microfluidics, among others. Despite this progress, multi-material printing with these methods remains challenging due to constraints associated with hardware modifications, control systems, cross-contamination, waste, and resin properties. Here, we report a new printing platform coined Meniscus-enabled Projection Stereolithography (MAPS), a vat-free method that relies on generating and maintaining a resin meniscus between a crosslinked structure and bottom window to print lateral, vertical, discrete, or gradient multi-material 3D structures with no waste and user-defined mixing between layers. We show that MAPS is compatible with a wide range of resins and can print complex multi-material 3D structures without requiring specialized hardware, software, or complex washing protocols. MAPS's ability to print structures with microscale variations in mechanical stiffness, opacity, surface energy, cell densities, and magnetic properties provides a generic method to make advanced materials for a broad range of applications.