nano-HA and Gel improves mechanical performance and biomineralization of 3D-printed nano-HA/Gel/CMC bone scaffolds

Abstract

In 3D printing scaffolds for bone tissue engineering applications, obtaining high degree of printability and shape fidelity while maintaining sufficient mechanical support are important obstacles. To address this issue, in this study, carboxymethyl cellulose (CMC) is used as a viscosity enhancer to improve shape fidelity of 3D-printed hydroxyapatite (nano-HA)/ gelatin (Gel) constructs. nano-HA/Gel/CMC hydrogels were 3D printed with varying compositions, gelatin ratios of 7.5 % and 15 %, a constant CMC ratio of 7.5 %, and HA ratios of 10 % and 20 %. After the EDC/NHS (100 mM:20 mM) crosslinking procedure, the effects of nano-HA and Gel concentrations were investigated by Fourier Transform Infrared (FTIR) analysis, printability studies, mechanical analysis, water contact angle, % water uptake, % weigh loss and pH studies. Additionally, bioactivity, cell culture and biomineralization studies were conducted. The printability was reduced when 20 % HA was added due to swelling with addition of nano-HA. The results indicated that nano-HA addition and 15 % Gel highly improves the mechanical properties and the highest compressive strength reached 2.6 MPa for HA10/G15/C7.5. MC3T3-E1 pre-osteoblasts were attached and proliferated on all study groups. Alizarin red staining and SBF studies showed high bioactivity of the samples. According to the experimental results, 3D-printed nano-HA/Gel/CMC scaffolds show potential for bone tissue engineering.