Assessing rheological properties of oxidized Moringa oleifera gum and carboxymethyl chitosan‐based self‐healing hydrogel for additive manufacturing applications

Abstract

Rheology plays a vital role in pneumatic three‐dimensional (3D) printing of hydrogels. This study investigates the rheological behavior of a novel self‐healing hydrogel (O‐MOG/CMCh) formed by a Schiff base crosslinking reaction between oxidized Moringa oleifera gum (O‐MOG), a biodegradable antimicrobial polysaccharide, and carboxymethyl chitosan (CMCh), a water‐soluble biocompatible chitosan derivative. Three hydrogel formulations were designed using 5% w/v of CMCh with varied concentrations of O‐MOG (3% w/v, 4% w/v, and 5% w/v) and evaluated through rheology analyses, including frequency sweeps, amplitude sweeps, oscillatory thixotropy, and gelation kinetics. These tests revealed that the material has shear thinning, self‐healing properties, a high linear viscoelastic region (LVE), and gel formation times (tgel) of 3.23–4.57 min. The hydrogel synthesized with 5% w/v of O‐MOG composition exhibited the best characteristics for printability based on rheological assessments, and this composition was used for further printing assessment, where bi‐layered 4 × 4 and 2 × 2 grids were successfully printed using 22 G (0.41 mm) and 23 G (0.34 mm) syringes. All the constructs had a printability index value of 1 ± 0.13 and spreading ratios <6.5, demonstrating the feasibility of employing the synthesized hydrogel as an acellular matrix via additive manufacturing. Self‐healing hydrogel was prepared by mixing the precursors through a cannula. Rheology was examined using standard tests for printability assessment. 3D printability was achieved using two different gauze syringes. Printability parameters were recorded and analyzed for the constructs.