Boron nitride nanotubes reinforced gelatin hydrogel-based ink for bioprinting and tissue engineering applications.

The rapid evolution of 3D bioprinting technique, very few biomaterials have been studied and utilised as ink solutions to produce structures. In this work, a polymeric nanocomposite hydrogel-based ink solution was developed using boron nitride nanotubes (BNNTs) reinforced gelatin for 3D bioprinting of scaffolds. The ink solutions and printed scaffolds were characterised for their printability, mechanical, thermal, water uptake, and biological properties (cell viability and inflammation). The viscoelastic behaviour of the scaffolds indicated the increase in storage modulus with an increase in BNNTs composition. Additionally, the compressive strength of the scaffolds increased from 9.43 ± 1.3 kPa to 30.09 ± 1.5 kPa with the addition of BNNTs. Similarly, the thermal stability of the scaffolds enhanced with an increase in BNNTs composition. Furthermore, the scaffolds with a higher concentration of BNNTs displayed resilience in cell culture media at 37 °C for up to 14 days compared with pure gelatin scaffolds. The cell viability results showed a decreased viability rate with an increased concentration of BNNTs scaffolds. However, BNNTs incubated with cells did not display cytokine inflammation. Therefore, this work provides a potential hydrogel-based ink solution for 3D bioprinting of biomimetic tissue constructs with adequate structural stability for a wide range of tissue engineering and regenerative medicine applications.