Vanillin chitosan miscible hydrogel blends and their prospects for 3D printing biomedical applications

In the present study, chitosan (CS) reacted with vanillin through a Schiff base reaction forming the vanillin-CS (VACS) derivative. FTIR and ¹H NMR spectra confirmed the derivatization of CS, the enhanced swelling behavior was long-established while XRD measurement stated the semicrystalline nature of the VACS derivative. In a further step, blends between CS and VACS were prepared in ratios CS/VACS 90/10 up to 10/90 w/w and the formation of hydrogen bonds was noticed through FTIR and XRD measurements. Structural optimizations were performed within the framework of density functional theory and interaction energies E_int were calculated. Collectively, these results along with viscosity measurements and SEM images prove the miscibility of CS/VACS blends. In the optimum CS/VACS ratios, inks for 3D printing application were prepared in different concentrations (3%w/v, 4%w/v, 5%w/v, 6%w/v). The augmentation of the samples' viscosity values influenced by the polymeric concentration was assessed while their thereafter printing application was conducted.