High performing additively manufactured bone scaffolds based on copper substituted diopside

TL;DR

This study demonstrates that copper-doped diopside scaffolds manufactured via robocasting exhibit enhanced mechanical, bioactive, and antibacterial properties, making them promising for bone tissue engineering applications.

Contribution

The paper introduces a novel 3D printed copper-doped diopside scaffold with improved fracture toughness, bioactivity, and antibacterial activity, advancing bioceramic scaffold design.

Findings

Copper is incorporated into diopside structure and improves fracture toughness.

Scaffolds with >80% porosity have compressive strengths exceeding cancellous bone.

Low copper levels promote cell proliferation and angiogenesis, while higher levels are cytotoxic.

Abstract

The inclusion of small amounts of copper is often reported to enhance the mechanical and biointegrative performance of bioceramics towards tissue engineering applications. In this work, 3D scaffolds were additively manufactured by robocasting of precipitation derived copper doped diopside. Compositions were chosen in which magnesium sites in diopside were substituted by copper up to 3 at.%. Microstructure, mechanical performance, bioactivity, biodegradability, drug release, biocompatibility, in vitro angiogenesis and antibacterial activity were studied. Results indicate that copper is incorporated in the diopside structure and improves materials fracture toughness. Scaffolds with more than 80% porosity exhibited compressive strengths exceeding that of cancellous bone. All compositions showed bioactivity and drug release functionalities. However, only samples with 0 to 1 at.% copper substitution showed favorable proliferation of osteogenic sarcoma cells, human umbilical vein endothelial cells and fibroblasts, while larger amounts of copper had cytotoxic behavior. In vitro angiogenesis was significantly enhanced by low levels of copper. Copper containing materials showed anti Escherichia coli activity, increasing with copper content. We show that across multiple indicators, copper substituted diopside of the composition CaMg0.99Cu0.01Si2O6, exhibits high performance as a synthetic bone substitute, comparing favorably with known bioceramics. These findings present a pathway for the enhancement of bioactivity and mechanical performance in printable bioceramics.