Calcium phosphate stability on melt electrowritten PCL scaffolds

Naghmeh Abbasi,Van Thanh Dau,Stephen Hamlet,Nam-Trung Nguyen

doi:10.1016/j.jsamd.2020.01.001

Naghmeh Abbasi, Van Thanh Dau + Show 2 more

Open Access

https://doi.org/10.1016/j.jsamd.2020.01.001

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Abstract

Calcium phosphate (CaP) coating on melt electrowritten (MEW) substrates is a potential candidate for bone regeneration influencing the interaction of osteoblasts with implanted scaffolds. Pretreatment to improve hydrophilicity of the hydrophobic polymer fibres affects subsequent coating with bioactive compounds like CaP. Therefore, this study evaluated the subsequent stability and structural properties of CaP coated MEW Poly-ε-caprolactone (PCL) scaffolds following pre-treatment with either argon-oxygen plasma or sodium hydroxide (NaOH). Scanning electron microscopy and μ-CT showed uniform CaP coating after one hour immersion in simulated body fluid following plasma pretreatment. Moreover, fourier transform infrared spectroscopy, energy dispersive spectrometry and X-ray diffraction analysis confirmed the presence of hydroxyapatite, tetracalcium phosphate and halite structures on the coated scaffolds. Contact angle measurement showed that the plasma pretreatment and CaP coating improved the hydrophilicity of the scaffold. However, the mechanical properties of the scaffolds were degraded after both plasma and NaOH treatments. The tensile stability was significantly improved following mineralization in plasma-treated scaffolds due to the smaller crystal size formed on the surface resulting in a dense CaP layer. The results obtained by thermogravimetric analysis also confirmed higher deposition of CaP particles on coated scaffolds following plasma modification. The results of this study show that plasma pre-treated mineralized MEW PCL scaffolds are sufficiently stable to be useful for further development in bone regeneration applications.

Highlights

The remodeling of the bone tissue around implanted materials is influenced by the surface charge and chemistry of the implanted materials [1]
scanning electron microscopy (SEM) images of the scaffold structures showed that the scaffolds retained their porous nature after CaP coating (Figure S1). 0.5 h SBF treatment did not fully cover the whole fibre surface (Figure S1-a), while immersion for 1 h provided uniform coating of the structures in both NaOH treatment þ CaP coating (NaeC) and Plasma treatment þ CaP coating (Plas-C) groups (Figure S1-b)
Following O2eAr plasma and NaOH surface modification, an apatite mineral layer was precipitated onto the surface of MEW PCL scaffolds by immersing them in simulated body fluid

Summary

Introduction

The remodeling of the bone tissue around implanted materials is influenced by the surface charge and chemistry of the implanted materials [1]. For tissue engineering purposes, PCL has some significant shortcomings such as slow degradation rate, hydrophobic properties and low cell adhesion [3]. The incorporation of CaP into PCL has yielded a class of hybrid biomaterials with remarkably improved mechanical properties, controllable degradation rates, and enhanced bioactivity as calcium and phosphate ions are essential for skeletal mineralization where. CaP coating imparts an increased surface roughness to coated scaffolds. Rough implant surfaces enhance the contact between the implant and the bone tissue improving subsequent integration [5]. Coating biocompatible substrates with these inorganic crystals has subsequently shown the significant bone growth and vascularization [6] including CaP coated electrospun poly (ethylene oxide terephthalate)Àpoly(buthylene terephthalate) scaffolds in vivo [7]

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