The Effect of Collagen-I Coatings of 3D Printed PCL Scaffolds for Bone Replacement on Three Different Cell Types

Abstract

Introduction The use of scaffolds in tissue engineering is becoming increasingly important as solutions need to be found to preserve human tissues such as bone or cartilage. Various factors, including cells, biomaterials, cell and tissue culture conditions, play a crucial role in tissue engineering. The in vivo environment of the cells exerts complex stimuli on the cells, thereby directly influencing cell behavior, including proliferation and differentiation. Therefore, to create suitable replacement or regeneration procedures for human tissues, the conditions of the cells’ natural environment should be well mimicked. Therefore, current research is trying to develop 3-dimensional scaffolds (scaffolds) that can elicit appropriate cellular responses and thus help the body regenerate or replace tissues. In this work, scaffolds were printed from the biomaterial polycaprolactone (PCL) on a 3D bioplotter. Biocompatibility testing was used to determine whether the printed scaffolds were suitable for use in tissue engineering. Material and Methods An Envisiontec 3D bioplotter was used to fabricate the scaffolds. For better cell-scaffold interaction, the printed polycaprolactone scaffolds were coated with type-I collagen. Three different cell types were then cultured on the scaffolds and various tests were used to investigate the biocompatibility of the scaffolds. Results Reproducible scaffolds could be printed from polycaprolactone. In addition, a coating process with collagen was developed, which significantly improved the cell-scaffold interaction. Biocompatibility tests showed that the PCL-collagen scaffolds are suitable for use with cells. The cells adhered to the surface of the scaffolds and as a result extensive cell growth was observed on the scaffolds. The inner part of the scaffolds, however, remained largely uninhabited. In the cytotoxicity studies, it was found that toxicity below 20% was present in some experimental runs. The determination of the compressive strength by means of the universal testing machine Z005 by ZWICK according to DIN EN ISO 604 of the scaffolds resulted in a value of 68.49 ± 0.47 MPa.

The Mineralization of Various 3D-Printed PCL Composites

“…This captures both images of the surface and laser scans. Surface-specific values such as surface roughness (center roughness Sa) can then be measured, analogous to our previous work [ 11 , 14 ]. To investigate the surface roughness before and after plasma treatment of the scaffolds, images were acquired using the 3D laser microscope and the surface roughness was measured at four random locations.…”

“…The PCL scaffolds were manufactured by using a 3D-BioPlotter (EnvisionTEC, Gladbeck, Germany) according to our previous work [ 11 , 14 ]. For this purpose, a 3D model of the scaffold was created in Autodesk Inventor (Autodesk Inventor 2019; Autodesk, San Raphael, CA, USA).…”

“…This should be based on the microstructure of bone, with main components consisting of collagen and HA. In theory, coating with collagen has improved cell adhesion [ 11 ] and cell profiling. The formation of HA on the collagen layer provides further improvement of cell profiling [ 12 ].…”

Influence of 3D Printing Parameters on the Mechanical Stability of PCL Scaffolds and the Proliferation Behavior of Bone Cells

“…Kim and Kim [ 41 ] achieved similar surface roughness values of 2.4 ± 0.2 µm with their self-healing collagen coatings, after treatment with water. In our previous work, we showed that the uncoated scaffolds had a surface roughness of 4.11 ± 0.27 µm and the collagen-coated samples had a roughness of 3.35 ± 0.3 µm [ 34 ]. The scaffolds were square, with a line infill.…”

“…To eliminate serum esterase activity, all samples at a specific time point had the medium removed and the cells washed. Staining was then performed according to a previously published protocol [ 34 ]. The evaluation was performed using an Olympus fluorescence microscope (BX51, Olympus, Osaka, Japan) at 5 different positions on the samples, at 5× and 10× magnification.…”