title: Printability of calcium phosphate: calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique.
abstract: In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (p<0.05) in the 3DP process parameters were found for CaP (30-110 μm):CaSO4 powders compared to CaP (<20 μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy.
authors.affiliation: School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, 121 Stranmillis Road, Belfast BT9 5AH, United Kingdom. Electronic address: zzhou02@qub.ac.uk.
authors.forename: Zuoxin
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, 121 Stranmillis Road, Belfast BT9 5AH, United Kingdom. Electronic address: f.buchanan@qub.ac.uk.
authors.forename: Fraser
authors.initials: F
authors.lastname: Buchanan
authors.affiliation: School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Health Sciences Building, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom. Electronic address: c.mitchell@qub.ac.uk.
authors.forename: Christina
authors.initials: C
authors.lastname: Mitchell
authors.affiliation: School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, 121 Stranmillis Road, Belfast BT9 5AH, United Kingdom. Electronic address: n.dunne@qub.ac.uk.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dunne
mesh_terms: D001842:Bone and Bones / Q000187:drug effects / Q000502:physiology*; D002130:Calcium Phosphates / Q000494:pharmacology*; D002133:Calcium Sulfate / Q000494:pharmacology*; D019245:Compressive Strength / Q000187:drug effects; D017886:Durapatite / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D011208:Powders; D011327:Printing / Q000379:methods*; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D017155:Wettability / Q000187:drug effects; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D011208:Powders; C485817:beta-tricalcium phosphate; D017886:Durapatite; D002133:Calcium Sulfate
keywords: Calcium phosphate; Calcium sulfate; Drop penetration; Particle size; Three-dimensional printing (3DP); Tissue engineering