Water-based hydroxyapatite photocurable feedstock for the manufacture of architectured parts by vat photopolymerization

abstract

Hydroxyapatite (HAp) is a biocompatible, osteoconductive, and biodegradable material widely studied for tissue engineering applications. Additive manufacturing, particularly vat photopolymerization technologies, enable the manufacture of custom-made, highly precise solutions. In this work, a colloidal approach was used to develop a water-based photocurable HAp-loaded feedstock with low viscosity, high solid loading (45 vol%), and low amount of organic compounds (10 vol%). Two distinct types of dispersants were evaluated to modify the surface of the HAp powders to enhance stability and dispersion. Rheological experiments were conducted to determine the optimal dispersant concentration, solid-loading, and pre-polymer content. Photorheological experiments were also performed to identify the printing parameters suitable for the vat photopolymerization technology. This work's approach, characterized by its low organic content, enabled a fast-debinding process (approximate to 13.5 h) when compared to the conventional photocurable ceramic-based feedstock. Different sintering temperatures were tested (1150 degrees C -> 1350 degrees C) and X-ray diffraction was used to evaluate the crystallographic composition at each temperature. Additionally, the relative density of the sintered parts was calculated and the compressive strength determined. The results demonstrated that sintering temperature enables high customization to meet specific end-user requirements. Architectured structures with interconnected porosity were successfully printed as a proof-of-concept of the potential printability of the developed aqueous-based feedstock. The eco-friendly photopolymerizable feedstock developed in this work should strongly impact the production cycle of resorbable bioceramic-based components.

keywords

POROUS HYDROXYAPATITE; IN-VITRO; SCAFFOLDS; SUSPENSIONS; CERAMICS; SLURRY; BIOMATERIALS; DISPERSION; ZIRCONIA; BEHAVIOR

subject category

Engineering; Materials Science

authors

Santos, S; Alves, MFRP; Miranda, G; Olhero, SM

Groups

G3 - Electrochemical Materials, Interfaces and Coatings
G5 - Biomimetic, Biological and Living Materials

Projects

Human Platelet Lysates-based Scaffolds for Interfacial Multi-tissue Repair (INTERLYNK)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

Simao Santos acknowledges University of Aveiro for the PhD grant (BI/REIT/11233/2024) . Manuel Alves acknowledges the FCT for the PhD grants (2021.06615.BD) . The authors acknowledge the European Union's Horizon 2020 research and innovation programme under the scope of InterLynk project (grant agreement No. 953169) . This work was also developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020) , UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) , financed by national funds through the FCT/MCTES (PIDDAC) .