Synthesis and structure-property correlations of polyurethanes for additive manufactured biomedical materials

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School of Chemical Technology | Doctoral thesis (article-based) | Defence date: 2024-03-15
Degree programme
83 + app. 71
Aalto University publication series DOCTORAL THESES, 27/2024
In recent decades, 3D printing has gained substantial attraction in the field of tissue engineering (TE) scaffold fabrication due to its exceptional precision, convenient manufacturing conditions, and rapid production capabilities. Among the various techniques, stereolithography (SLA) and direct ink writing (DIW) are the most applicable techniques in this field. However, the availability of biodegradable and biocompatible synthesized polymers, particularly from the polyurethane (PU) family, remains limited for the purpose of 3D printing. The primary objective of this research was to develop biodegradable and biocompatible PUs, encompassing both isocyanate-based and non-isocyanate-based (NIPUs) polyurethanes. These polymers were specifically designed for applications in nerve and skin regeneration. A solvent-free approach was utilized to synthesize photo-cross linkable PU resins, effectively applied for the SLA technique. Furthermore, the incorporation of PEGylated graphene oxide nanoparticles into the resin composite was executed to confer conductivity, a crucial attribute for scaffolds intended for nerve regeneration. Then the nerve guidance conduits (NGCs) were printed with very precise geometry by SLA. Additionally, a novel generation of isocyanate-free PUs was successfully synthesized utilizing six distinct diamines. This endeavor aimed to investigate the correlation between polymer structure and resultant properties. Based on the chemical and physical characteristics of the synthesized NIPUs, a specific variant containing cystamine (NIPU-Cys) was identified for further exploration in 3D printing applications. To enhance its properties, the chosen polymer was combined with an antibacterial chitosan derivative, synthesized by a doctoral researcher within the Polymer Technology Research Group at Aalto University (Isabella Lauren). This antibacterial hydrogel composite was effectively 3D printed using the DIW technique, presenting the potential for wound healing applications.
Supervising professor
Seppälä, Jukka, Prof., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
Thesis advisor
Baniasadi, Hossein, Dr., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
Lipponen, Sami, Dr., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
Borandeh, Sedigheh, Dr., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
polyurethane, non-isocyanate polyurethane, stereolithography, tissue regeneration, photo-crosslinking, direct ink writing, conductivity
Other note
  • [Publication 1]: Farzan, Afsoon; Borandeh, Sedigheh; Zanjanizadeh Ezazi, Nazanin;Lipponen, Sami; A. Santos, Hélder; Seppälä, Jukka; 3D scaffolding of fast photocurable polyurethane for soft tissue engineering by stereolithography: Influence of materials and geometry on growth of fibroblast cells. Elsevier. European Polymer Journal, volume 139, issue October (2020) 109988.
    DOI: 10.1016/j.eurpolymj.2020.109988 View at publisher
  • [Publication 2]: Farzan, Afsoon; Borandeh, Sedigheh; Seppälä, Jukka; Conductive polyurethane/PEGylated graphene oxide composite for 3D-printed nerve guidance conduits. European Polymer Journal, volume 167, issue February (2022) 111068.
    DOI: 10.1016/j.eurpolymj.2022.111068 View at publisher
  • [Publication 3]: Farzan, Afsoon; Borandeh, Sedigheh; Baniasadi, Hossein; Seppälä, Jukka; Environmentally friendly polyurethanes based on non-isocyanate synthesis. Express Polymer Letters, volume 18, No.1, Pages 88-101 (2024).
    DOI: 10.3144/expresspolymlett.2024.7 View at publisher
  • [Publication 4]: Laurén, Isabella; Farzan, Afsoon; Teotia, Arun; C. Lindfors, Nina; Seppälä, Jukka; Direct ink writing of biocompatible chitosan/non-isocyanate polyurethane/cellulose nanofiber hydrogels for wound-healing applications. International Journal of Biological Macromolecules, volume 259, part 2, issue February (2024).
    DOI: 10.1016/j.ijbiomac.2024.129321 View at publisher