Inorganic polyphosphate, a paradigm changer in 3D printing of β -tricalcium phosphate based materials for bone tissue surgery

作者：Meik Neufurth, David Molter, Xiaoqing La, Changxin Wu, Hiroshi Ushijima, Heinz C. Schröder, Xiaohong Wang, Wernér E.G. Müller · 发表于：Biomedical Materials · 年份：2025 · DOI：10.1088/1748-605x/ae084b · 被引用次数：1 · 研究领域：Bone Tissue Engineering Materials、Dental Implant Techniques and Outcomes

Abstract β -Tricalcium phosphate ( β -TCP) is widely used as a material for bone implants due to its excellent biocompatibility, biodegradability, and osteoconductivity, as well as its osteoinductive properties. Here, we demonstrate that the regenerative potential of this material can be significantly enhanced when incorporated into a matrix of inorganic polyphosphate (polyP), a physiological, metabolically active polymer composed of phosphate residues linked by high-energy phosphoanhydride bonds. A 3D-printable hydrogel was developed containing suspended β -TCP and amorphous calcium-polyP nanoparticles (Ca-polyP-NP; the water-insoluble depot form of polyP), as well as NaH 2 PO 4 as the monomeric precursor of the polymeric, water-soluble Na-polyP. Heating the printed scaffold to 700 °C causes condensation of NaH 2 PO 4 , resulting in the formation of a Na-polyP glass melt that embeds the Ca-polyP-NP and β -TCP particles. The final scaffolds exhibited the necessary porosity, with pore sizes ranging from 10 to 100 µm (average 84 µm), which are suitable for bone ingrowth, along with the required mechanical stability. The morphogenetically active polyP component is released from the 3D-printed porous scaffolds in appropriate amounts, significantly increasing both the proliferation and energy-dependent differentiation of mesenchymal stem cells (MSCs) into mineralizing osteoblasts compared to polyP-free β -TCP scaffolds. Moreover, enhanced formation of collagen fibers and hydroxyap...