3D-Printed Bioactive Ca₃SiO₅ Bone Cement Scaffolds with Nano Surface Structure for Bone Regeneration

Silicate-based materials are widely explored for bone regeneration due to their favorable physicochemical properties and osteogenic potential. Current approaches include fabrication of porous scaffolds using various methods, with 3D printing being the most effective for controlling pore architecture. However, high-temperature sintering required for ceramic scaffolds often leads to structural shrinkage and reduced accuracy in pore design. In contrast, bioactive silicate cements like tricalcium silicate (C₃S) can self-set under mild conditions, offering mechanical strength and the ability to incorporate drugs. Despite these advantages, the integration of 3D printing with bioactive silicate cements remains underexplored. Prior research has established the benefits of 3D-printed scaffolds but has not fully addressed the challenges of maintaining structural integrity and bioactivity without high-temperature processing. This gap motivated the development of a new fabrication method that preserves scaffold geometry while enhancing biological performance. Additionally, the role of surface topography in influencing cell behavior is not fully understood in the context of 3D-printed silicate scaffolds. No prior work had resolved how to combine 3D printing with nanoscale surface modification to improve bone regeneration outcomes. The need for a bioactive scaffold with controllable structure and surface features remains unmet in current research.

This study aimed to develop a novel 3D-printed tricalcium silicate (C₃S) bone cement scaffold that avoids high-temperature sintering while maintaining structural accuracy. The specific problem addressed was the loss of pore structure control due to thermal shrinkage in traditional ceramic scaffolds. The motivation stemmed from the need for a bioactive scaffold that supports drug delivery and enhances cell interactions. The researchers sought to demonstrate the feasibility of room-temperature 3D printing of C₃S scaffolds with controllable pore architecture. Additionally, the study aimed to evaluate the impact of surface nanotopography on cell behavior and bone regeneration. The goal was to create a scaffold that integrates drug-loading capabilities and bioactive surface features. The authors proposed that such a scaffold could serve as an advanced biomaterial for bone repair applications. The study's findings may provide a new direction for developing bioactive implants with enhanced osteogenic properties.

The study employed 3D printing at room temperature to fabricate tricalcium silicate (C₃S) scaffolds with controlled pore structures. The scaffolds were designed to maintain dimensional accuracy without high-temperature sintering. Two model drugs were incorporated into the scaffolds to test drug-loading capabilities. A surface modification process was developed to create nanotopography on the pore walls. The resulting nanoneedle structures were analyzed for their ability to influence cell behavior. Rat bone-marrow stem cells (rBMSCs) were cultured on the scaffolds to assess attachment, spreading, and alkaline phosphatase (ALP) activity. In vivo experiments were conducted to evaluate the scaffolds' effect on bone regeneration in animal models. The study compared the performance of modified scaffolds with unmodified C₃S scaffolds to determine the impact of surface topography on biological outcomes.

The 3D-printed C₃S scaffolds were successfully fabricated at room temperature with controllable pore structures. The scaffolds retained their dimensional accuracy without requiring high-temperature sintering. Drug-loading experiments demonstrated that two model drugs could be incorporated into the scaffolds with location-controlled release profiles. Surface modification created nanoneedle structures on the pore walls, which were confirmed through imaging techniques. The modified scaffolds showed enhanced rat bone-marrow stem cell (rBMSC) attachment and spreading compared to unmodified scaffolds. Alkaline phosphatase (ALP) activity was significantly higher on the nanotopography-modified surfaces. In vivo experiments revealed that the modified scaffolds supported improved bone regeneration compared to pure C₃S scaffolds. The study demonstrated that combining 3D printing with surface nanotopography can enhance the bioactivity of silicate-based scaffolds.

The authors concluded that 3D-printed C₃S bone cement scaffolds with controllable nanotopography can enhance bone regeneration. The study demonstrated that room-temperature fabrication preserves scaffold geometry without high-temperature shrinkage. The presence of nanoneedle structures on the scaffold surfaces improved cell attachment and ALP activity. Drug-loading capabilities were confirmed, with controlled release profiles observed in the scaffolds. In vivo results supported the hypothesis that surface modification enhances osteogenic outcomes. The findings suggest that the combination of 3D printing and nanotopography can create bioactive scaffolds for bone repair. The authors propose that these scaffolds may serve as implantable biomaterials with improved regenerative potential. The study highlights the importance of surface features in influencing cell behavior and bone regeneration outcomes.