Year

2019

Degree Name

Master of Philosophy

Department

Intelligent Polymer Research Institute

Abstract

3D printing has made a significant breakthrough in the field of tissue engineering; mainly due to its possibility to create scaffolds with more control over spatial arrangement and ability to manufacture patient specific replacements. The lack of different biomaterial inks that can fulfil the requirements of both additive manufacturing and specific biological requirements is a major bottleneck that limits the potential of this technique for clinical translation. Herein, we present the development of ink formulations based on a photo-curable chitosan for 3D printing of scaffolds for wound healing application.

Chitosan, a linear polysaccharide well-established for wound healing application, was modified into a water soluble and photo-curable form, namely methacryloyl chitosan (ChiMA). The product was characterised by FTIR and 1HNMR. A range of ChiMA/MC inks were formulated for extrusion printing in which methyl cellulose (MC) serves as a rheological modifier. These ink formulations were subjected to several screening tests, including an extrudability test and a semi-quantitative assessment of printability, to identify the appropriate combinations of CHiMA and MC for further extrusion printing studies. Physicochemical properties of the crosslinked form of the inks (hydrogels) were characterised as part of the screening test to establish a correlation between ink composition and concentration on the final scaffold. Based on the screening results, 2%ChiMA/3%MC and 3%ChiMA/2%MC inks were selected as the lead ink formulations for rheological studies. It was found that both the selected inks had a yield stress less than 350 Pa, a value well below the plug-flow regime of 1866 Pa, which also demonstrated excellent shear thinning properties upon being extruded through the nozzle. Self-recovery data proved the inks’ ability for regaining structural integrity following printing, thus confirming their utilization as feeding inks for extrusion-based 3D printing...

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.