Development of a clinically relevant 3D in vitro spinal cord injury model using bioprinted GelMA hydrogels

Rad, Maryam Alsadat

Development of a clinically relevant 3D in vitro spinal cord injury model using bioprinted GelMA hydrogels

Rad, Maryam Alsadat

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Publication Type:: Thesis
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Rad, Maryam Alsadat
dc.date.accessioned	2023-09-08T01:40:18Z
dc.date.available	2023-09-08T01:40:18Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/171989
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_US.UTF-8
dc.description.abstract	Traumatic spinal cord injury (SCI) occurs primarily in young males and the elderly due to transport accidents, acts of violence, falls, and sporting activity, which usually involves very rapid mechanical injury. The complexity of the central nervous system (CNS) network makes it challenging to understand the reactions of different types of CNS cells. This study has concentrated on simulating a clinically relevant 3D in vitro SCI in terms of mechanical forces and biological responses. For this purpose, 3D Gelatin Methacryloyl (GelMA) hydrogels at various volume concentrations embedded with NG108-15 neuronal and C6 astrocyte-like cells were bioprinted. The bioprinted GelMA hydrogels with 5% (w/v) concentration were the most appropriate matrix for a 3D in vitro SCI model due to optimal printability, structural stability, high cell viability, and optical transparency. To design a valid SCI model, the micromechanical properties of bioprinted GelMA hydrogels were assessed using Brillouin microspectroscopy as a non-invasive and label-free method. The results demonstrated that 5% (w/v) acellular GelMA hydrogel had similar mechanical properties to native neural tissue. Finally, the TA Instruments Electroforce Impaction system was utilised to simulate a spinal cord contusion injury using a 3D bioprinted GelMA hydrogel. The contusion injury was modelled at velocities of 1000 and 3000 mm.s⁻¹ with displacement to 1, 2 and 4 mm to investigate cellular responses to displacement depth and injury velocity. Astrocytic expression of glial fibrillary acidic protein (GFAP) volume and metabolic activity of C6 astrocyte-like cells increased with increasing velocity and depth displacement over 10 days post impaction. However, neuronal cells showed the opposite behaviour, where βIII-tubulin (a neuronal marker) labelled cells exhibited significant neurite outgrowth in non-injured control samples than in post-injury samples over 10 days. In summary, a 3D SCI model was developed and presented in this thesis which was clinically relevant and mimicked the in vivo mechanical characteristics of an injury. In addition, the responses of both astrocytes and neuronal cells were similar to those observed in vivo after injury. The model developed within this study leaves scope for further development to increase the complexity of bioprinted structures with multiple cell types. This model possesses the potential for use in evaluating how injury biomechanics, such as displacement and velocity, affects the pathophysiological outcomes of cells and which biomechanical parameters are dominant in determining injury severity in vivo. The use of these preclinical models may aid in development of improved animal models of SCI.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/171989/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Maryam Alsadat Rad
dc.rights	au.edu.uts.lib/nph
dc.title	Development of a clinically relevant 3D in vitro spinal cord injury model using bioprinted GelMA hydrogels	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Traumatic spinal cord injury (SCI) occurs primarily in young males and the elderly due to transport accidents, acts of violence, falls, and sporting activity, which usually involves very rapid mechanical injury. The complexity of the central nervous system (CNS) network makes it challenging to understand the reactions of different types of CNS cells. This study has concentrated on simulating a clinically relevant 3D in vitro SCI in terms of mechanical forces and biological responses. For this purpose, 3D Gelatin Methacryloyl (GelMA) hydrogels at various volume concentrations embedded with NG108-15 neuronal and C6 astrocyte-like cells were bioprinted. The bioprinted GelMA hydrogels with 5% (w/v) concentration were the most appropriate matrix for a 3D in vitro SCI model due to optimal printability, structural stability, high cell viability, and optical transparency. To design a valid SCI model, the micromechanical properties of bioprinted GelMA hydrogels were assessed using Brillouin microspectroscopy as a non-invasive and label-free method. The results demonstrated that 5% (w/v) acellular GelMA hydrogel had similar mechanical properties to native neural tissue. Finally, the TA Instruments Electroforce Impaction system was utilised to simulate a spinal cord contusion injury using a 3D bioprinted GelMA hydrogel. The contusion injury was modelled at velocities of 1000 and 3000 mm.s⁻¹ with displacement to 1, 2 and 4 mm to investigate cellular responses to displacement depth and injury velocity. Astrocytic expression of glial fibrillary acidic protein (GFAP) volume and metabolic activity of C6 astrocyte-like cells increased with increasing velocity and depth displacement over 10 days post impaction. However, neuronal cells showed the opposite behaviour, where βIII-tubulin (a neuronal marker) labelled cells exhibited significant neurite outgrowth in non-injured control samples than in post-injury samples over 10 days. In summary, a 3D SCI model was developed and presented in this thesis which was clinically relevant and mimicked the in vivo mechanical characteristics of an injury. In addition, the responses of both astrocytes and neuronal cells were similar to those observed in vivo after injury. The model developed within this study leaves scope for further development to increase the complexity of bioprinted structures with multiple cell types. This model possesses the potential for use in evaluating how injury biomechanics, such as displacement and velocity, affects the pathophysiological outcomes of cells and which biomechanical parameters are dominant in determining injury severity in vivo. The use of these preclinical models may aid in development of improved animal models of SCI.

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http://hdl.handle.net/10453/171989