Manufacturing controls for the fabrication of tissue scaffolds with graded microstructures

It is well known that mechanical properties are an important consideration for scaffold design in tissue engineering. Commonly scaffold stiffness and macroscale (200 μm to 1 mm) pore interconnection size are investigated for their influence on new tissue growth. Microscale (2 to 20 μm) porosity has received less attention, but recent in vivo studies highlight the sensitivity of bone ingrowth to scaffold microstructure. Currently there are not fabrication methods to vary microporosity within a single structure. This work provides a control method for solid freeform fabrication processes that enables precise material placement control and the ability to interchange materials. We demonstrate the control method with the fabrication of combinatorial samples; samples which test multiple micro- and macropore design options within a single structure. The ability to fabricate scaffolds with this design will lead to more efficient in vivo evaluation of the effect of porosity on scaffold viability.