Fabrication and characterization of three-dimensional (3D) scaffolds based on alginate, methyl cellulose and chitosan, for tissue engineering applications

• Κύριος συγγραφέας: Φερμανή, Μαρία
• Άλλοι συγγραφείς: Fermani, Maria
• Γλώσσα: English
• Έκδοση: 2021
• Θέματα: Βιοϊατρική μηχανική; Τρισδιάστατη εκτύπωση; Μηχανική ιστών; Biomedical engineering; 3D Printing-tissue engineering

This postgraduate thesis explored the preparation and printing of hydrogel inks composed of alginate calcium, methyl cellulose, chitosan or trimethyl chitosan and bioactive glass as fillers to manufacture bone scaffolds. In the first part of the study, a low-cost 3D hydrogel printer was developed by modification of a FFF (Fused Filament Fabrication) printer. The modification was successful, and the printer tested using alginate/methyl cellulose/chitosan (or trimethyl chitosan inks) to print rectangular scaffolds with dimensions about 20x20x1.5 mm with square pores. The printability was evaluated using the image analysis program ImageJ. Printability tests included pore size measurements, right-angle tests, and line thickness versus pressure measurements. All inks and scaffolds were characterized using various techniques, such as XRD, FTIR spectroscopy and SEM. Swelling tests were performed in normal saline solution. It was found that chitosan increased the stability of alginate/methyl cellulose scaffolds however substitution of chitosan with trimethylchitosan increased the scaffold’s stability drastically. The introduction of conventional and bioactive glass in the polymeric matrix reduced the stability in normal saline solutions. Finally, mineralization experiments were performed in the glass containing scaffolds by immersing in simulated body fluid solution. The results showed the formation of hydroxyapatite on the polymeric scaffold while their stability in normal saline solution was significantly increased. The possible mechanism leading to increased stability is based on the formation of apatite crystals in the polymeric network. In conclusion, 3D printed scaffolds containing alginate/methyl cellulose/ trimethyl chitosan are good candidates for bone tissue engineering applications.