Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters

Hamid Ait Said,Ayoub Bayoussef,Hassan Noukrati,Allal Barroug,Hicham Ben Youcef,Hassane Oudadesse

doi:10.3390/min11020213

Abstract

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.

Highlights

Bone fracture is one of the most common body injuries and is accompanied by social productivity loss, individual disability, and expensive treatment costing billions of dollars per year [1]
The peaks of the CSM polymer are not detected in the HA-CSM diffractograms; this could be attributed to the small amount of polymer introduced in the matrix
It is noted that there was no marked difference with the X-ray diffraction (XRD) patterns of the composite containing low molecular weight chitosan, indicating that the polymer molecular weight does not affect the composite structure

Summary

Introduction

Bone fracture is one of the most common body injuries and is accompanied by social productivity loss, individual disability, and expensive treatment costing billions of dollars per year [1]. Mechanical strength is one of the most crucial characteristics of biomaterials. These materials must be able to withstand mechanical forces while being continually in contact with bone tissues and fluids. Since these biomaterials are designed to be used as bone implants, it is worth bearing in mind as reference values that the resistance to compression varies from about 90 to 209 MPa and from 1.5 to 45 MPa for human cortical bone and cancellous bone, respectively [2]. Calcium phosphate (CaP) is one of the most common classes of biomaterials investigated for orthopedic applications [3]

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Conclusion