Novel sintering-free scaffolds obtained by additive manufacturing for concurrent bone regeneration and drug delivery: Proof of concept

• Published in: Materials Science & Engineering C 2019-01, Vol.94, p.426-436
• Main Authors: Marques, Catarina F., Olhero, Susana M., Torres, Paula M.C., Abrantes, João C.C., Fateixa, Sara, Nogueira, Helena I.S., Ribeiro, Isabel A.C., Bettencourt, Ana, Sousa, Aureliana, Granja, Pedro L., Ferreira, José M.F.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Antibiotics; Bacteria; Biomedical materials; Bone growth; Bone regeneration; Bone Regeneration - drug effects; Bone Regeneration - physiology; Calcium; Calcium phosphates; Cell Count; Cell Death - drug effects; Chitosan; Composite materials; Composite scaffolds; Crosslinking; Drug delivery; Drug Delivery Systems; Drug Liberation; Elastic Modulus; Extrudability; Extrusion; Fabrication; Fibroblasts - cytology; Fibroblasts - drug effects; Humans; Hydroxyapatite; Imaging, Three-Dimensional; Infant, Newborn; Inks; Levofloxacin; Levofloxacin - pharmacology; Local-drug-delivery; Manufacturing; Materials science; Mechanical properties; Microbial Sensitivity Tests; Microstructure; Polymer matrix composites; Polymers; Powders; Regeneration; Regeneration (physiology); Rheological properties; Robocasting; Scaffolds; Sintering; Sintering (powder metallurgy); Sintering-free biphasic CaP; Spectrum Analysis, Raman; Staphylococcus aureus - drug effects; Strong interactions (field theory); Studies; Substitute bone; Surgical implants; Temperature; Tissue Scaffolds - chemistry; Viscosity
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2018.09.050

Advances on the fabrication of sintering-free biphasic calcium phosphate (BCP)/natural polymer composite scaffolds using robocasting as additive manufacturing technique are presented in the present work. Inks with high amounts of BCP powders (45 vol%) containing different HA/β-TCP ratios, in presence of crosslinked polymer, were successfully fine-tuned for extrusion by robocasting. The non-existence of sintering step opened the possibility to obtain drug loaded scaffolds by adding levofloxacin to the extrudable inks. The drug presence induced slightly changes on the rheological behaviour of the inks, more emphasized for the BCP compositions with higher amounts of β-TCP, and consequently, on the microstructure and on the mechanical properties of the final scaffolds. The strong interaction of β-TCP with chitosan difficult the preparation of suitable rheological inks for printing. Drug delivery studies revealed a fast release of levofloxacin with a high burst of drug within the first 30 min. Levofloxacin loaded samples also presented bacteria growth inhibition ability, proving that antibiotic was not degraded during the fabrication process and its bactericidal efficacy was preserved. From the results obtained, the composite scaffolds containing higher amounts of HA (around 80% HA/20% β-TCP) constitute a promising bi-functional synthetic bone substitute for simultaneous local bone regeneration and infection treatments. Biphasic composite scaffolds (CaP based + natural polymer) with potential applications in concurrent bone regeneration and drug delivery. [Display omitted] •Sintering-less CaPs/natural polymer scaffolds were fabricated by robocasting.•The absence of sintering enables the addition of drug to the extrudable inks.•Drug delivery studies revealed a fast release of levofloxacin.•Levofloxacin loaded scaffolds presented bacteria growth inhibition ability.