TY  - JOUR
A1  - Götz, Lisa-Marie
A1  - Holeczek, Katharina
A1  - Groll, Jürgen
A1  - Jüngst, Tomasz
A1  - Gbureck, Uwe
T1  - Extrusion-Based 3D Printing of Calcium Magnesium Phosphate Cement Pastes for Degradable Bone Implants
JF  - Materials
N2  - This study aimed to develop printable calcium magnesium phosphate pastes that harden by immersion in ammonium phosphate solution post-printing. Besides the main mineral compound, biocompatible ceramic, magnesium oxide and hydroxypropylmethylcellulose (HPMC) were the crucial components. Two pastes with different powder to liquid ratios of 1.35 g/mL and 1.93 g/mL were characterized regarding their rheological properties. Here, ageing over the course of 24 h showed an increase in viscosity and extrusion force, which was attributed to structural changes in HPMC as well as the formation of magnesium hydroxide by hydration of MgO. The pastes enabled printing of porous scaffolds with good dimensional stability and enabled a setting reaction to struvite when immersed in ammonium phosphate solution. Mechanical performance under compression was approx. 8–20 MPa as a monolithic structure and 1.6–3.0 MPa for printed macroporous scaffolds, depending on parameters such as powder to liquid ratio, ageing time, strand thickness and distance.
KW  - magnesium phosphate cement
KW  - extrusion-based 3D printing
KW  - degradable implant
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246110
SN  - 1996-1944
VL  - 14
IS  - 18
ER  - 
TY  - JOUR
A1  - Brückner, Theresa
A1  - Meininger, Markus
A1  - Groll, Jürgen
A1  - Kübler, Alexander C.
A1  - Gbureck, Uwe
T1  - Magnesium Phosphate Cement as Mineral Bone Adhesive
JF  - Materials
N2  - Mineral bone cements were actually not developed for their application as bone-bonding agents, but as bone void fillers. In particular, calcium phosphate cements (CPC) are considered to be unsuitable for that application, particularly under moist conditions. Here, we showed the ex vivo ability of different magnesium phosphate cements (MPC) to adhere on bovine cortical bone substrates. The cements were obtained from a mixture of farringtonite (Mg\(_3\)(PO\(_4\))\(_2\)) with different amounts of phytic acid (C\(_6\)H\(_{18}\)O\(_{24}\)P\(_6\), inositol hexaphosphate, IP6), whereas cement setting occurred by a chelation reaction between Mg\(^{2+}\) ions and IP6. We were able to show that cements with 25% IP6 and a powder-to-liquid ratio (PLR) of 2.0 g/mL resulted in shear strengths of 0.81 ± 0.12 MPa on bone even after 7 d storage in aqueous conditions. The samples showed a mixed adhesive–cohesive failure with cement residues on the bone surface as indicated by scanning electron microscopy and energy-dispersive X-ray analysis. The presented material demonstrated appropriate bonding characteristics, which could enable a broadening of the mineral bone cements’ application field to bone adhesives
KW  - magnesium phosphate cement
KW  - phytic acid
KW  - bone adhesive
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193052
SN  - 1996-1944
VL  - 12
IS  - 23
ER  -