Biocompatible colloidal feedstock for material extrusion processing of bioceramic-based scaffolds

Abstract

Nowadays an enormous effort has been made to impulse the incorporation of additive manufacturing (AM) approaches in the biomedical sector. One of the most recognized biomaterials for this end is bioceramics such as hydroxyapatite (HA), but unfortunately, ceramics present a lack of accessible technologies based on AM. Consequently, the development of new methodologies which enable the manufacture of bioceramic-based scaffolds is imperative. A large number of publications on polymer–ceramic composite processed by Material Extrusion are available, so far, the maximum ceramic loading reached is still a parameter to improve. Recently an alternative colloidal processing technique to prepare ceramic-based composite feedstock for material extrusion has been proposed. It has been demonstrated that tailoring the surface of the ceramic particles enables the processing of high ceramic loading composites by AM. This article shows the potential of the colloidal approach to process biocompatible PLA/HA feedstock increasing the homogeneity of the bioceramic phase into the composite. The feedstock characterization shows that HA surface modification makes possible the successful dispersion and the ceramic load increase without modifying the biocompatibility. The ceramic load increase does not modify the melting properties of the polymeric matrix required for the 3D printing process. This methodology allows for the first time the development of a final 3D printed composite structure with contents up to 72 wt% of HA by Material Extrusion. This colloidal approach paves the way to transfer the use of additive manufacturing techniques mainly devoted to polymeric biomaterials to other types of biomaterials such as bioceramics. Highlights: A colloidal approach for 3D printing of PLA/HA composites is proposed. HA surface modification made possible a load increase with high dispersion. The characterization of a PLA/HA feedstock for 3D printing is established. Biocompatible PLA/HA feedstock is processed by AM in customized structures. Colloidal approach allows the processing of 3D structures with 72 wt% of HA.