The Mineralization of Various 3D-Printed PCL Composites

Abstract

In this project, different calcification methods for collagen and collagen coatings were compared in terms of their applicability for 3D printing and production of collagen-coated scaffolds. For this purpose, scaffolds were printed from polycaprolactone PCL using the EnvisionTec 3D Bioplotter and then coated with collagen. Four different coating methods were then applied: hydroxyapatite (HA) powder directly in the collagen coating, incubation in 10× SBF, coating with alkaline phosphatase (ALP), and coating with poly-L-aspartic acid. The results were compared by ESEM, µCT, TEM, and EDX. HA directly in the collagen solution resulted in a pH change and thus an increase in viscosity, leading to clumping on the scaffolds. As a function of incubation time in 10× SBF as well as in ALP, HA layer thickness increased, while no coating on the collagen layer was apparently observed with poly-L-aspartic acid. Only ultrathin sections and TEM with SuperEDX detected nano crystalline HA in the collagen layer. Exclusively the incubation in poly-L-aspartic acid led to HA crystals within the collagen coating compared to all other methods where the HA layers formed in different forms only at the collagen layer.

Towards Polycaprolactone-Based Scaffolds for Alveolar Bone Tissue Engineering: A Biomimetic Approach in a 3D Printing Technique

“…Currently, aliphatic polyester-based scaffolds are gaining popularity over humanorigin living bone tissue surgically transplanted (autograft) [99]. Research in this field focuses on composite scaffolds based on PCL, with HA and natural polymers (such as CGI or CS) [100][101][102][103]. In contrast to autografts (see Figure 6), PCL-based scaffolds, supplemented with HA, CGI, and CS, provide more control over the structure, mechanical properties, and composition.…”

Nano-Topographically Guided, Biomineralized, 3D-Printed Polycaprolactone Scaffolds with Urine-Derived Stem Cells for Promoting Bone Regeneration

“…However, the surface of the synthetic polymer scaffolds is bioinert and has the disadvantages of low wettability and weak cell adhesion and thus cannot provide favorable microenvironments for osteogenesis in vivo. Therefore, the biomineralization of HA onto surfaces of synthetic polymer scaffolds can form a bioactive surface with higher wettability and better osteoinductivity, which provides a more favorable microenvironment for osteoblast adhesion, proliferation, and differentiation [ 20 , 21 ]. Currently, soaking in a simulated body fluid (SBF) that contains similar ion levels to those of human body fluid is one of the most common biomineralization approaches and has the advantages of being a simple procedure and having high efficiency [ 22 ].…”

About the Mechanical Strength of Calcium Phosphate Cement Scaffolds

“…In this work, both systems, namely sintered ceramics and 3D-printed CPC scaffolds, were to be compared with regard to their mechanical properties [22,26] to determine if 3D-printed scaffolds exhibited similar mechanical properties to bone. To achieve this, we first focused on 3D printing more than 12 layers [27][28][29] so that we could produce comparably sized specimens. The working hypotheses were that (1) as the number of layers increased, the mechanical strength of the 3D-printed CPC scaffolds would increase and (2) the internal needle diameter would influence the mechanical strength, which would better mimic the mechanical strength of the bone than what is possible with sintered ceramics.…”