Pressure-Assisted Coating of Ceramics on 3D-Printed Polymeric Scaffolds

Tissue engineering relies on scaffolds that support cell growth and tissue regeneration. While 3D-printed polymeric scaffolds offer structural flexibility, their mechanical and biological properties often fall short for clinical use. Coating these scaffolds with bioactive ceramics like β-tricalcium phosphate (β-TCP) can improve their performance. However, existing coating methods struggle to achieve uniform coverage without structural damage. This gap motivated the development of a new approach that preserves scaffold integrity while enhancing surface properties. Prior research has shown that biomimetic coatings can be inconsistent in thickness and adhesion. No prior work had resolved the challenge of applying thick, defect-free ceramic layers to complex 3D-printed geometries. This paper introduces a method that addresses these limitations by combining infiltration, compaction, and heat treatment. The study aims to provide a scalable solution for coating scaffolds with bioactive ceramics.

The goal of this research is to develop a reliable method for coating 3D-printed polymeric scaffolds with β-TCP using pressure-assisted coating (PAC). The specific problem addressed is the difficulty of achieving uniform ceramic coatings without damaging the scaffold structure. The motivation stems from the need for scaffolds that support cell attachment and tissue integration. Current methods often result in weak interfaces or structural defects. This study seeks to optimize PAC parameters to ensure consistent coating quality. The researchers propose that PAC can overcome the limitations of biomimetic approaches. The method is tested on different scaffold geometries and materials to assess its versatility. The study also evaluates the impact of PAC on surface properties and cell behavior. The ultimate aim is to provide a reproducible technique for enhancing scaffold functionality.

The PAC method involves four sequential steps: infiltration of β-TCP particles into the scaffold pores, dehydration of the ceramic slurry, compaction under pressure, and heat treatment. The infiltration speed is set at 400 mm/min to ensure even distribution. Dehydration is carried out to remove excess liquid before compaction. The scaffold is then compressed at approximately 8 MPa to enhance particle adhesion. Heat treatment at 65 °C stabilizes the ceramic layer without deforming the scaffold. The coated samples are analyzed using micro-CT to assess structural integrity. Laser and scanning electron microscopy are used to evaluate coating uniformity. The bonding strength is compared to a biomimetic coating method. The method is tested on various scaffold shapes and sizes to confirm its adaptability.

The PAC method produced scaffolds with uniform β-TCP coatings and no structural deformation. Micro-CT and electron microscopy confirmed the absence of defects in the coated samples. The contact angle decreased significantly from 75.2 ± 1.4° to 39.6 ± 9.6° after coating. Surface roughness increased from 0.66 ± 0.08 to 6.89 ± 0.26 μm. Cell attachment improved, with a doubling of cell count on the third day of culture. The interface bonding strength was higher than that of the biomimetic approach. A 10 mm × 10 mm conical scaffold was successfully coated with a 58 ± 4 μm β-TCP layer. The method was also applied to poly(lactic-co-glycolic acid) (PLGA) scaffolds as a proof of concept. These results suggest that PAC can be used for various scaffold geometries and materials.

The authors propose that PAC is a viable method for coating 3D-printed scaffolds with β-TCP without compromising structural integrity. The method achieves uniform coatings with improved surface properties and cell attachment. The study shows that PAC outperforms the biomimetic approach in terms of bonding strength. The researchers suggest that the method is adaptable to different scaffold shapes and sizes. The results support the use of PAC for enhancing scaffold functionality. The described process can be applied to various polymers, including PLGA. The study confirms that PAC can be used to coat complex geometries with consistent results. These findings suggest that PAC is a promising technique for tissue engineering applications.