(65g) Rational Fabrication of Polymer-Graphene Based Scaffolds/Devices Using 3D Bioprinting and Microfluidics to Control Stem Cell Differentiation and Fate Commitment

The focus of my research endeavors is to elucidate the mechanisms underlying the relationship between advanced biomaterials and cellular interactions. Particularly I am pursuing research efforts in the development of functional biomaterials targeting 3D bioprinting for tissue/organ regeneration, drug/gene delivery for cancer therapy/theranostics, and bioinspired polymeric films/devices for biomedical applications. Each of these efforts have resulted in valuable contributions to the field and posed broader impact in translational research; however, here I will mainly discuss our past, present and future research efforts regarding the 3D bioprinted scaffolds for stem cell-based therapies and neural regeneration.

The clinical use of stem cell-based therapies for regeneration purposes is promising; however, it is limited due to the current difficulties associated with 1) non-scalable and reversible differentiation protocols; 2) design of implantable scaffolds with desired properties mimicking the complex 3D extracellular matrix microenvironment; and 3) precise control on the final fate of the implanted cell population.^1-3 In order to address these limitations, my research is concentrated on biomaterial design for stem cell-laden implantable scaffolds-based cellular therapies with a particular interest in stem cell differentiation and fate commitment for neural regeneration.

In our previous studies, we uniquely integrated various physical and chemical cues (using longitudinal micropatterns, surface gradient of chemicals/growth factors and neurotropic factors loaded micro/nanoparticles) in porous polymeric films providing controlled release of active components, proper microenvironment for cells and directed nerve growth.⁴ In order to circumvent the limitations of 2D cell culture platforms, we exhibited significant control on mesenchymal stem cells (MSCs) to Schwann cell-like phenotypes (SCs) transdifferentiation via chemical stimuli by changing the 3D microstructural/mechanical properties of gelatin-based conduits.⁵ Moreover, to eliminate the need for expensive chemicals and growth factors for chemical stimuli-based stem cell differentiation, we also demonstrated successful transdifferentiation of MSCs into SCs via sole electrical stimuli on conductive graphene-based 2D substrates.⁶ This study selected as cover art for Advanced Healthcare Materials Journal, received Star Award from the Society for Biomaterials and resulted in provisional patent filing. In order to provide a mechanistic understanding of transdifferentiation process, we have recently conducted a detailed proteomics analysis and identified significantly regulated proteins and related cellular pathways upon MSCs to SCs transdifferentiation via chemical stimuli.⁷

Based on this background, we currently focus on designing 3D bioprinted, graphene microcircuits integrated, cell-laden, conductive, biodegradable and implantable conduits/scaffolds with tunable microstructural/mechanical properties. The main idea is that the synergetic effect of electrical and microstructural cues applied via sophisticated conduit design have the potential to eliminate the multiple procedures for in vitro transdifferentiation and enable precise control in situ-in vivo transdifferentiation and fate commitment accompanied by directed migration and axonal regeneration. We also conduct a detailed mechanistic investigation to understand the regulated genes, proteins and cellular pathways upon transdifferentiation using the synergetic effect. For this study, I have recently submitted NIH Pathway to Independence Award (Parent K99/R00) proposal, which is currently pending. Another ongoing effort is to use 3D graphene foams integrated to the biodegradable polymeric films possessing surface micropatterns and porous microstructure as scaffolds for stem cell differentiation via electrical stimuli for neural regeneration. In this study, the purpose is to use electrical stimuli within a conductive 3D microstructure to control stem cell differentiation. In alignment with these studies, another aspect of my current research is focused on developing biodegradable polymer based, 3D microstructured, flexible electronic devices/films using a novel microfluidic approach coupled with 3D origami as an easy, fast, cost effective and green fabrication method. Our efforts for this study have resulted in submission of an invention disclosure and together with 3D bioprinting, it will be the main foundation of my future research endeavors. These flexible electronic devices hold promising potential to be used in various biomedical, tissue engineering and robotics applications. Thus, we investigate the biointerface of these devices for the purpose of microfluidics and organ/lab-on-a-chip applications for neural regeneration, which will be the main future directions.

Overall, the ultimate goal will be to make realistic 3D tissue models that mimic the actual cellular arrangement of tissues/organs using different strategies and mechanistically elucidating material-cell and cell-cell interactions.

References:

1. Uz, M.; Das Suprem, R.; Ding, S.; Sakaguchi Donald, S.; Claussen Jonathan, C.; Mallapragada Surya, K., Advances in Controlling Differentiation of Adult Stem Cells for Peripheral Nerve Regeneration. Advanced Healthcare Materials 0 (0), 1701046.
2. Uz, M, and Mallapragada, S.K.; Smart Materials for Nerve Regeneration and Neural Tissue Engineering. Smart Materials for Tissue Engineering: Applications, Qun Wang (Ed.), Royal Society of Chemistry, 2017, pp.382-408. (Print ISBN: 978-1-78262-484-4)
3. J. Sandquist, M. Uz, A.D. Sharma, B.B. Patel, S.K. Mallapragada, D.S. Sakaguchi, Stem Cells, Bioengineering, and 3-D Scaffolds for Nervous System Repair and Regeneration: G.L. Zhang and L.D. Kaplan (Eds.), Neural Engineering: From Advanced Biomaterials to 3D Fabrication Techniques, Springer International Publishing 2016, pp. 25-81.
4. Uz, M., Sharma, A., Adhikari, P., Sakaguchi, D., and Mallapragada, S.K., “Development of Multifunctional Films for Peripheral Nerve Regeneration Conduits, Acta Biomat. (2017). Available online. https://doi.org/10.1016/j.actbio.2016.09.039
5. Uz, M., Buyukoz, M., Sharma, A., Sakaguchi, D., Altinkaya, S., and Mallapragada, S.K., “Gelatin-Based 3D Conduits for Transdifferentiation of Mesenchymal Stem Cells into Schwann-cell Like Phenotypes”, Acta Biomat., 53, 293-306 (2017).
6. Das, S.,^#Uz, M.,^# Ding, S., Lentner, M., Hondred, J., Cargill, A., Sakaguchi, D.S., Mallapragada, S., and Claussen, J., “Electrical Differentiation of Mesenchymal Stem Cells into Schwann Cell-Like Phenotypes using Inkjet Printed Graphene Circuits”, Healthcare Mater., 6(7), 1601087 (2017). Journal cover image. doi: 10.1002/adhm.201601087. (^# These authors put equal contribution)
7. Anup D. Sharma, Jayme Horning, Metin Uz, Pawel Ciborowski, Surya K. Mallapragada, Howard E. Gendelman, and Donald S. Sakaguchi; “Proteomics Analysis of Mesenchymal to Schwann Cell Transdifferentiation.”, Journal of Proteomics, June 2017, In Press, https://doi.org/10.1016/j.jprot.2017.06.011