Robocasting of Cu2+ & La3+ doped sol-gel glass scaffolds with greatly enhanced mechanical properties: Compressive strength up to 14 MPa


This research details the successful fabrication of scaffolds by robocasting from high silica sol-gel glass doped with Cu2+ or La3+. The parent HSSGG composition within the system SiO2-CaO-Na2O-P2O5 [67% Si - 24% Ca - 5% Na - 4% P (mol%)] was doped with 5 wt% Cu2+ or La3+ (Cu5 and La5). The paper sheds light on the importance of copper and lanthanum in improving the mechanical properties of the 3-D printed scaffolds. 1 h wet milling was sufficient to obtain a bioglass powder ready to be used in the preparation of a 40 vol% solid loading paste suitable for printing. Moreover, Cu addition showed a small reduction in the mean particle size, while La exhibited a greater reduction, compared with the parent glass. Scaffolds with macroporosity between 300 and 500 mu m were successfully printed by robocasting, and then sintered at 800 degrees C. A small improvement in the compressive strength (7-18%) over the parent glass accompanied the addition of La. However, a much greater improvement in the compressive strength was observed with Cu addition, up to 221% greater than the parent glass, with compressive strength values of up to similar to 14 MPa. This enhancement in compressive strength, around the upper limit registered for human cancellous bones, supports the potential use of this material in biomedical applications. Statement of Significance 3D porous bioactive glass scaffolds with greatly improved compressive strength were fabricated by robocasting from a high silica sol-gel glasses doped with Cu2+ or La3+. In comparison to the parent glass, the mechanical performance of scaffolds was greatly improved by copper-doping (>220%), while a modest increase of 9% was registered for lanthanum-doping. Doping ions (particularly La3+) acted as glass modifiers leading to less extents of silica polymerisation. This favoured the milling of the glass powders and the obtaining of smaller mean particle sizes. Pastes with a high solid loading (40 vol%) and with suitable rheological properties for robocasting were prepared from all glass powders. Scaffolds with dimensions of 3 x 3 x 4 mm and macro-pore sizes between 300 and 500 mu m were fabricated. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.



subject category

Engineering; Materials Science


Ben-Arfa, BAE; Neto, S; Salvado, IMM; Pullar, RC; Ferreira, JMF

our authors


R.C. Pullar wishes to thank the FCT (Fundacao para a Ciencia e a Tecnologia, Portugal) Grant IF/00681/2015 for supporting this work. B. A. E. Ben-Arfa thanks FCT grant BIONANOSCULP PTDC/EPH-PAT/6281/2014 for supporting him during this work. This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement.

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