3D-printed silicate porous bioceramics using a non-sacrificial preceramic polymer binder

Creating complex geometries with silicate bioceramics remains a challenge despite their bioactive properties. Traditional methods struggle to maintain structural integrity and desired porosity in printed parts. While bioglass-ceramics are known for their ability to bond with bone, their shaping limits their use in tissue engineering. Prior research has shown that sacrificial binders are commonly used in 3D printing, but they often leave behind residues or require additional processing steps. This gap motivated the search for a non-sacrificial binder that could streamline the manufacturing process. The need for a binder that also contributes to the final ceramic structure is unmet in current literature. No prior work had resolved the issue of achieving controlled porosity and mechanical strength simultaneously. This paper's contribution lies in its novel approach to using a preceramic polymer as both a binder and a reactive component.

The study aimed to develop a new 3D-printing method for silicate bioceramics using a preceramic polymer as a non-sacrificial binder. The goal was to overcome the limitations of traditional shaping techniques by integrating the binder into the final ceramic structure. The researchers focused on wollastonite-based bioceramics due to their known bioactive properties. They wanted to control the geometry and mechanical properties of printed parts through this method. The motivation stemmed from the need for scaffolds with tailored porosity and strength for biomedical applications. The study also aimed to evaluate the viability of using this method for tissue engineering scaffolds. The researchers wanted to assess whether this approach could yield biocompatible materials suitable for in vivo use. This work sought to bridge the gap between ceramic processing and 3D-printed biomedical structures.

The researchers used a preceramic polymer as a binder in a powder-based 3D-printing process. The process involved combining wollastonite powder with a silicon resin and reactive fillers. The resin acted as a structural support during printing and later reacted with the fillers to form the desired ceramic phases. The printed parts were sintered to complete the transformation into bioceramics. Mechanical properties were tested using a ball-on-three-balls test. The printed discs were analyzed for density, porosity, and morphology. Scaffold structures with multi-scale porosity were also produced and tested for compressive strength. In vitro tests were conducted to evaluate cell viability and cytotoxicity.

The 3D-printed discs had a total porosity of approximately 64 vol% and a biaxial flexural strength of around 6 MPa. The scaffolds showed a total porosity of about 80 vol% and a compressive strength of 1 MPa. The preceramic polymer successfully reacted with the fillers to form the desired bioceramic phases. The printed structures maintained their designed geometries after sintering. The mechanical performance met the requirements for biomedical scaffolds. In vitro assays showed no cytotoxic effects and good cell viability. The solubility tests indicated that the material could dissolve in TRIS/HCl. These findings suggest the method is suitable for producing biocompatible and structurally viable scaffolds.

The study demonstrated that a preceramic polymer can serve as a non-sacrificial binder in 3D-printed silicate bioceramics. The method enabled the production of parts with controlled porosity and mechanical strength. The printed scaffolds maintained their designed geometries and possessed suitable compressive strength. The in vitro tests confirmed the material's biocompatibility and lack of cytotoxicity. The researchers propose that this approach offers a streamlined process for manufacturing bioceramics. The method eliminates the need for sacrificial binders and additional processing steps. The results suggest that the technique is suitable for tissue engineering applications. The authors suggest that further work could explore scaling up the process for clinical use.