Polyethylene Oxide and Silicon-Substituted Hydroxyapatite Composite: A Biomaterial for Hard Tissue Engineering in Orthopedic and Spine Surgery

Abstract

Background: Tissue engineering and biomaterials have made it possible to innovate bone treatments for orthopedic and spine problems. The aim of this study is to develop a novel polyethylene oxide (PEO)/silicon-substituted hydroxyapatite (Si-HA) composite to be used as a scaffold for hard tissue engineering in orthopedic and spine procedures.

Materials and methods: The composite was fabricated through the electrospinning technique. The applied voltage (5 kV) and PEO concentration (5%) were fixed. Processing parameters such as the flow rates (20 μl/min and 50 μl/min), distances from capillary tube to the collector (130 mm and 180 mm), spinning time (10 min and 20 min), and concentration of Si-HA (0.2% and 0.6%) were explored to find the optimum conditions to produce fine composite fibers.

Results: Scanning electron microscope images showed that 5% PEO, 5% PEO/0.2% Si-HA, and 5% PEO/0.6% Si-HA fibers were successively produced. Flow rates and working distances showed significant influence on the morphology of the polymeric and composite fibers. A high flow rate (50 μl/min) and a larger working distance (180 mm) resulted in larger fibers. The comparison between the mean fiber diameter of 5% PEO/0.2% Si-HA and 5% PEO/0.6% Si-HA showed to be significantly different. As the Si-HA concentration increased, certain fibers were having particles of Si-HA that were not properly integrated into the polymer matrix.

Conclusions: Synthesis of a novel biomaterial for hard tissue scaffold through electrospinning was successful. In general, PEO/Si-HA fibers produced have the desired characteristics to mimic the extracellular matrix of bone.

Keywords: Biomaterial; hard tissue engineering; neurosurgery; orthopedics; polyethylene oxide; silicon-substituted hydroxyapatite; spine surgery.

Figure 1

Mean fiber diameter of 5% polyethylene oxide fibers versus processing parameters (flow rate and working distance) at a spinning time of 20 min. *P < 0.05

Figure 2

Mean fiber diameter of 5% polyethylene oxide at 10 min and 20 min, as per the different flow rates and working distances. *P < 0.05

Figure 3

Comparison of the mean fiber diameters of 5% polyethylene oxide/0.2 silicon-substituted hydroxyapatite, 5% polyethylene oxide/0.6 silicon-substituted hydroxyapatite, and 5% polyethylene oxide (10 and 20 min). P values indicate significant difference between 5% polyethylene oxide and 5% polyethylene oxide/0.2% silicon-substituted hydroxyapatite in the 20 μl/min at 180 mm and in the 50 μl/min at 130 mm and 180 mm, respectively. Significant difference was also observed between 5% polyethylene oxide and 5% polyethylene oxide/0.6% silicon-substituted hydroxyapatite. Note: The 5% polyethylene oxide/0.6% silicon-substituted hydroxyapatite fibers electrospun at 20 μl/min and at 180 mm were invalid and thus were not included

Figure 4

Scanning electron microscopy images of lower magnification of 5% polyethylene oxide electrospun at 130 mm and a flow rate of 50 μl/min

Figure 5

Scanning electron microscopy pictures of 5% polyethylene oxide at different processing parameters, while spinning for 10 min

Figure 6

Scanning electron microscopy image of 5% polyethylene oxide/0.6% silicon-substituted hydroxyapatite showing bioceramic particles not fully integrated in the polymer matrix

Figure 7

The “root-like” shape of 5% polyethylene oxide/0.6% silicon-substituted hydroxyapatite at a flow rate of 20 μl/min and a working distance of 130 mm

Figure 8

Comparison of the spectra of 5% polyethylene oxide, 5% polyethylene oxide/0.2% silicon-substituted hydroxyapatite, and 5% polyethylene oxide/0.6% silicon-substituted hydroxyapatite

Figure 9

Method of measurement using auto computer-aided design software. Different zones are observed. One zone characterized by a white color and shows the high-density pixels, whereas the zone characterized by a gray color shows the low-density pixels