In vitro evaluation of PCL and P(3HB) as coating materials for selective laser melted porous titanium implants
Creators: name: Grau, Michael
name: Matena, Julia
name: Teske, Michael
name: Petersen, Svea
name: Aliuos, Pooyan
name: Roland, Laura
name: Grabow, Niels
name: Escobar, Hugo Murua
name: Gellrich, Nils-Claudius
name: Haferkamp, Heinz
name: Nolte, Ingo
Publisher: name: Basel : MDPI AG
Year: 2017
Subjects: subject: Osteoblast
subject: Poly(3-hydroxybutyrate)
subject: Polycaprolactone
subject: Titanium scaffold
subject: Biocompatibility
subject: Bone
subject: Cell adhesion
subject: Cells
subject: Coatings
subject: Cytology
subject: Deposits
subject: Elastic moduli
subject: Metal implants
subject: Osteoblasts
subject: Plastic coatings
subject: Plating
subject: Polymeric implants
subject: Polymers
subject: Scanning electron microscopy
subject: Titanium
subject: Bone implant material
subject: Energy dispersive x-ray
subject: Environmental scanning electron microscopies (ESEM)
subject: In-vitro evaluation
subject: Poly-3-hydroxybutyrate
subject: Porous titanium implants
subject: Selective laser melting
subject: Titanium scaffolds
subject: Scaffolds (biology)
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: Titanium is widely used as a bone implant material due to its biocompatibility and high resilience. Since its Young's modulus differs from bone tissue, the resulting "stress shielding" could lead to scaffold loosening. However, by using a scaffold-shaped geometry, the Young's modulus can be adjusted. Also, a porous geometry enables vascularisation and bone ingrowth inside the implant itself. Additionally, growth factors can improve these effects. In order to create a deposit and release system for these factors, the titanium scaffolds could be coated with degradable polymers. Therefore, in the present study, synthetic poly-"-caprolactone (PCL) and the biopolymer poly(3-hydroxybutyrate) (P(3HB)) were tested for coating efficiency, cell adhesion, and biocompatibility to find a suitable coating material. The underlying scaffold was created from titanium by Selective Laser Melting (SLM) and coated with PCL or P(3HB) via dip coating. To test the biocompatibility, Live Cell Imaging (LCI) as well as vitality and proliferation assays were performed. In addition, cell adhesion forces were detected via Single Cell Force Spectroscopy, while the coating efficiency was observed using environmental scanning electron microscopy (ESEM) and energy-dispersive X-ray (EDX) analyses. Regarding the coating efficiency, PCL showed higher values in comparison to P(3HB). Vitality assays revealed decent vitality values for both polymers, while values for PCL were significantly lower than those for blank titanium. No significant differences could be observed between PCL and P(3HB) in proliferation and cell adhesion studies. Although LCI observations revealed decreasing values in cell number and populated area over time on both polymer-coated scaffolds, these outcomes could be explained by the possibility of coating diluent residues accumulating in the culture medium. Overall, both polymers fulfill the requirements regarding biocompatibility. Nonetheless, since only PCL coating ensured the maintenance of the porous implant structure, it is preferable to be used as a coating material for creating a deposit and release system for growth factors.