3D bioprinting of human induced pluripotent stem cells derived neural progenitors using bioinks containing drug-releasing microspheres

Date

2022-05-03

Authors

Sharma, Ruchi

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Abstract

Tissue engineering employs biological and engineering principles to create functional substitutes for damaged tissue by combining biomaterial scaffolds with drug delivery devices. 3D (three-dimensional) bioprinting has grown into a potential manufacturing technology for creating such scaffolds. The key problem with this technology is printing scaffolds while preserving cell viability, functioning, and structural integrity. This dissertation explores the features of bioink formed from the combination of natural biomaterials and their influence on the bioprinting process. This work aims to explain the development of bioprinting processes for producing tissue with neural progenitor cells (NPCs) derived from human induced pluripotent stem cells (hiPSCs) and fibrin-based bioink encapsulated with microspheres for neural tissue engineering applications. Moreover, hiPSCs are stem cells made from skin or blood cells that have been reprogrammed into an embryonic-like pluripotent state, which means they can be used to make any kind of human cell that is needed for therapeutic use. To accomplish these goals, this study pursues three objectives: first, to bioprint healthy hiPSC-derived NPCs with guggulsterone microspheres; second, to examine the physical and mechanical properties of bioink with and without guggulsterone microspheres; and finally, to bioprint Parkinson’s disease (PD) patient-specific hiPSC-derived NPCs with guggulsterone microspheres for advanced drug-screening. The RX1 bioprinter from Aspect Biosystems, which is based on microfluidics, was used to manufacture domes of 1 cm in diameter using our fibrin-based bioink containing guggulsterone microspheres and hiPSC-derived NPCs. Bioprinted healthy brain tissues had over 90% cellular viability one day after printing. Tissues healthy brain tissues had over 90% cellular viability one day after printing. Tissues displayed early and mature neuronal markers TUJ1 (15.3%), dopamine marker TH (8.1%), and other genes (NURR1, LMX1B, TH, and PAX6) that expressed in midbrain dopaminergic neurons. The storage and loss modulus, viscosity, and shear rates of bioprinted constructs with and without microspheres were also determined. Physical properties such as microstructure, porosity, swelling, and biodegradability were also studied. According to our findings, the elastic modulus of constructs with microspheres was higher than without microspheres. The integration of microspheres resulted in mechanical strength, indicating their potential for use in neural tissue engineering in the future. A bioprinted model of PD was generated utilising hiPSC-derived NPCs from PD patients. NPCs were differentiated into dopaminergic neurons. These models can efficiently identify viable compounds in the early phases of drug development. Finally, I validated that using a microsphere-laden bioink to bioprint hiPSC-derived NPCs can stimulate neural tissue development.

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Keywords

3D Bioprinitng, Human induced pluripotent stem cells, Neural Progenitor Cells, Fibrin, Bioink, Dopaminergic neurons, Mechanical properties, Parkinson's disease

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