Cellulose-Based Scaffolds with Prolonged Dexamethasone Release for Bone Tissue Engineering

The implantation of bone substitutes is frequently accompanied by inflammation. To reduce the inflammatory response and enhance cell adhesion, proliferation, and differentiation, scaffolds are often loaded with anti-inflammatory drugs. In this study, cellulose and cellulose/hydroxyapatite (1:1 by weight) scaffolds were developed. Structural analysis using SEM and micro-computed tomography revealed that the morphology of the scaffolds met the requirements for bone tissue engineering. The scaffolds were initially loaded with dexamethasone sodium phosphate; however, the drug was released very rapidly. To prolong its release, cationic groups were introduced into the cellulose macromolecules by amination with 2-chloro-N,N-diethylethylamine hydrochloride in an alkaline medium. Dexamethasone sodium phosphate was then immobilised on aminated cellulose and aminated cellulose/HAp scaffolds at concentrations of 157 mg/g and 87 mg/g, respectively. Due to ionic interactions between the cationic groups in the scaffolds and the anionic groups of the drug molecules, drug release was effectively prolonged. After 24 h, only about 6-7% of the drug had been released, with complete release occurring after 170 h. The cationic groups in the scaffold framework facilitated the adsorption and sustained release of dexamethasone sodium phosphate.