Development and characterization of wollastonite cement for bone tissue engineering

Abstract

As human life expectancy increases and degenerative bone diseases become more common, especially in the elderly, the need to develop synthetic biomaterials for bone repair and regeneration is becoming increasingly important. In this context, wollastonite-based cements (CaSiO3) have been shown to be a viable biomaterial alternative due to characteristics such as biocompatibility, bioactivity and osteoconductivity. CaSiO3-based cements are formed from a reaction between a solution containing phosphate ions (HPO4-) and CaSiO3 powder, resulting in a paste that spontaneously hardens at room temperature, precipitating hydroxyapatite and a glassy silicate. However, the mechanical properties of these materials are still not satisfactory, which is often a limiting factor for the use of wollastonite cements in several applications. In order to improve the mechanical properties of cements, studies have been directed to the application of various materials as reinforcing agents through the formation of a composite material, such as carbon fibers and glass fibers. However, many of these fibers have been shown to be toxic to cells, hindering their clinical application. One material capable of overcome such restrictions is cellulose nanocrystals (CNCs). CNCs are the crystalline part of cellulosic materials, which can be extracted from trees and a variety of plants. As a reinforcement material, CNCs have some advantages, including biodegradability, biocompatibility, high abundance, low cost and excellent mechanical properties. Therefore, the main objective of this project is to incorporate CNCs in wollastonite cement in order to promote a change in the final mechanical properties of this cement, without loss of biocompatibility and bioactivity aiming at applications in bone tissue repairs in a more comprehensive way, reducing the risk of fracture. Thus, this work presents an innovative study regarding the production of a cement based on wollastonite with good biocompatibility and adequate mechanical properties through the insertion of a small amount of CNCs in the cement. (AU)