Fabrication of Mechanically Reinforced Gelatin/Hydroxyapatite Bio-Composite Scaffolds by Core/Shell Nozzle Printing for Bone Tissue Engineering.

Haeri Kim,Youngwon Koo,Geunhyung Kim,Hanjun Hwangbo

doi:10.3390/ijms21093401

Haeri Kim, Youngwon Koo + Show 2 more

Open Access

https://doi.org/10.3390/ijms21093401

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Abstract

In tissue engineering, biocompatible scaffolds are used as 3D cell niches to provide a similar environment to that of native tissue for seeded cells to regenerate the target tissue. When engineering bone tissue, high mechanical strength and calcium phosphate composition are essential factors to consider. In this study, we fabricated biocompatible composite scaffolds composed of synthetic polymers (polycaprolactone (PCL) and poly (vinyl alcohol) (PVA)), natural polymers (gelatin and collagen) and bioceramic (hydroxyapatite; HA) for bone tissue engineering. The synthetic polymers were used to enhance the mechanical properties of the composite scaffolds while the natural protein-based polymers were used to enhance various cellular activities, such as cell adhesion and proliferation. Meanwhile, the bioceramic was introduced to promote osteogenic differentiation. Composite scaffolds were evaluated for their physical characteristics, such as mechanical, swelling and protein absorbing properties as well as biological properties (cell proliferation, alkaline phosphatase (ALP) activities and calcium deposition) with human osteoblast-like cells (MG63). Consequently, incorporation of hydroxyapatite into the gelatin/PVA (C-GPH) scaffold showed 5-fold and 1.5-fold increase in calcium deposition and ALP activities, respectively compared to gelatin/PVA scaffold (C-GP). Moreover, compressive modulus also increased 1.8-fold. Integration of PCL core into gelatin/PVA/hydroxyapatite scaffold (C-PGPH) further amplified the compressive modulus 1.5-fold. In conclusion, the scaffold that is reinforced with HA particles and integrated with PCL core of the struts showed significant potential in field of bone tissue engineering.

Highlights

Tissue engineering, which is achieved by integration of biological components such as cells and growth factors with biocompatible scaffolds, has the potential to regenerate damaged tissues
The barrel temperature was set to 37 ◦C to facilitate easy flow of the gelatin/poly(vinyl alcohol) (PVA)/HA mixture in the nozzle
Regarding the fabrication of C-PGPH scaffold, the core-shell nozzle with 860-μm shell diameter, which is much larger than the nozzle size (200 μm) of the single nozzle used for the fabrication of compared to gelatin/PVA scaffold (C-GP) or coated gelatin/PVA/HA scaffolds (C-GPH) scaffold, was used, yet have produced similar strut diameter

Summary

Introduction

Tissue engineering, which is achieved by integration of biological components such as cells and growth factors with biocompatible scaffolds, has the potential to regenerate damaged tissues. An ideal scaffold for bone engineering should be able to promote cell attachment/growth, promote osteoconduction and osteoinduction, have sufficient mechanical competence to sustain a mechanical load and be biodegradable to allow new tissue formation [8]. Natural polymers, such as alginate, cellulose, gelatin and collagen are widely used because of their ready availability and established biocompatibility, while synthetic polymers are renowned for low immunological effects [9]. Poly(ε-caprolactone) (PCL), is a form of polyester that has been widely used for tissue engineering due to its relative resistance to chemical reactions and excellent mechanical properties [10]. PCL has been applied to regenerate load-bearing tissues (cartilages and bones) of the human body

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