One step 3D printing of surface functionalized composite scaffolds for tissue engineering applications

A successful approach widely used in materials science to adapt approved materials to specific applications is to design their surface properties. A main challenge in this area is the development of processing routes enabling for a simple but efficient surface design of complex shaped geometries. Against this background, this work aimed at the implementation of self-assembly principles for surface functionalization of 3D-printed poly(lactic-co-glycolic acid) (PLGA)-based constructs with macro- and microporous geometries via precision extruding deposition. Methods: Three-component melts from PLGA, CaCO3 and amphiphilic polymers (poly(2-oxazoline) block copolymer) were printed and their bulk and surface properties were studied. Results: Melts with up to 30 mass % of CaCO3 could be successfully printed with homogeneously distributed mineral particles. PLGA degradation during the printing process was temperature and time dependent: the molecular weight reached 10 to 15% of the initial values after ca. 120 min of heat exposure. Filament surfaces from melts containing CaCO3 show an increasing microroughness along with increasing CaCO3 content. Surface roughness and amphiphilic polymer content improve scaffold wettability with both factors showing synergistic effects. The CaCO3 content of the melts affected the inner filament structure during in vitro degradation in PBS, resulting in a homogeneous mineral particle-associated microporosity for mineral contents of 20 mass % and above. Conclusions: These results provide novel insights into the behavior of three-component melts from PLGA, CaCO3 and amphiphilic polymers during precision extruding deposition and show for the first time that self-assembly processes can be used to tailor scaffolds surface properties under such processing conditions.