Pressure-Assisted Coating of Ceramics on 3D-Printed Polymeric Scaffolds
Pressure-assisted coating (PAC) is introduced to coat 3D-printed polymeric scaffolds with β-tricalcium phosphate (β-TCP) for tissue engineering applications. The method consists of four steps: infiltration of ceramic particles into the porous structure of the polymeric scaffold, dehydration of the slurry, compaction of ceramic particles around the scaffold, and heat treatment. The optimal coating is obtained at an infiltration speed of 400 mm/min followed by complete dehydration, compaction under ca. 8 MPa pressure, and subsequent heat treatment at 65 °C. The outcome is a uniformly coated scaffold with no deformation or structural defects, as confirmed by micro-CT analysis and laser and scanning electron microscopy. Scaffolds coated using the PAC method present superior interface bonding strength compared to those coated with a biomimetic approach. The contact angle decreased from 75.2 ± 1.4° for the uncoated scaffold to 39.6 ± 9.6° for the PAC specimen. PAC also increased the surface roughness from 0.66 ± 0.08 to 6.89 ± 0.26 μm and doubled the number of attached cells on the 3rd day of culture. The described method is applicable to different structures, object sizes, pore sizes, and shapes. For instance, in-depth coating of a 10 mm × 10 mm (D × H) cone with a 58 ± 4 μm-thick layer of β-TCP can be achieved using PAC. The method can be used to coat other polymers, such as poly(lactic-co-glycolic acid) (PLGA). Successful coating of β-TCP on 3D-printed PLGA scaffolds is also presented as a proof of concept.