Support-less ceramic 3D printing of bioceramic structures using a hydrogel bath.

Bone tissue has limited ability to regenerate when defects are large or complex. Traditional scaffolds for bone regeneration often fail to mimic the intricate structure of natural bone. Researchers have explored ceramic 3D printing to create bioceramic scaffolds that support bone growth. However, the fabrication of overhanging or complex structures remains a challenge. Current methods rely on sacrificial supports that add time and cost. These supports can also cause damage to the final product when removed. No prior work had resolved the issue of support-free fabrication of complex bioceramic structures. This gap motivated the development of a new printing approach. The need for a method that avoids sacrificial supports is clear. A solution that enables faster and more reliable fabrication of complex bone substitutes is required.

This study aimed to develop a support-less ceramic printing (SLCP) method to fabricate complex bioceramic structures. The goal was to eliminate the need for sacrificial supports during 3D printing. The researchers focused on creating a process that reduces fabrication time and material use. They also aimed to improve the mechanical and biological performance of the printed scaffolds. The motivation was to enable the production of hierarchical bone-like structures. The method needed to support overhanging features without additional structures. The team sought to test whether SLCP could lead to better cell adhesion and growth. The ultimate aim was to provide a scalable and efficient technique for bone tissue engineering.

The researchers used a hydrogel bath composed of pluronic P123, a temperature-sensitive material. The hydrogel provided mechanical support during the printing process. Bioceramic ink was extruded directly into the hydrogel bath. The hydrogel also facilitated the cement reaction to cure the bioceramic. The team tested the method on complex structures like the mandible and maxillofacial bones. They compared SLCP scaffolds to those made using conventional printing. Surface roughness and cell interactions were measured using standard techniques. The hydrogel was removed after printing without damaging the structure.

SLCP scaffolds showed significantly higher cell adhesion compared to conventional scaffolds. The surface roughness of SLCP scaffolds was greater, promoting better cell attachment. Cell growth rates were higher on SLCP scaffolds, indicating improved biocompatibility. Osteogenic protein expression was also elevated in SLCP-printed structures. The method enabled the fabrication of overhanging and complex bone-like structures. Hybrid scaffolds with embedded cells were successfully produced using SLCP. The hydrogel bath allowed for precise control of shape and structure. No cracks or breaks were observed in the final printed constructs.

The authors propose that SLCP is a viable method for fabricating complex bioceramic scaffolds. The hydrogel bath eliminates the need for sacrificial supports during printing. This reduces both processing time and material consumption. The method supports the creation of hierarchical bone structures with overhangs. SLCP scaffolds exhibit enhanced cell adhesion and growth due to surface roughness. The technique allows for co-printing of cells and bioceramics in a cell-friendly environment. The results suggest that SLCP can be used to manufacture complex bone substitutes. The authors suggest that this method may improve outcomes in bone tissue engineering.