

3D Printing for Bone Tissue Engineering
We investigate the fabrication of scaffolds with engineered porosity from bioactive glass, using the selective laser sintering (SLS) process and an extrusion-based process, for bone tissue engineering. Pore geometry in the scaffold is shown to play a crucial role as it affects not only the mechanical properties and degradation over time but also the amount of bone regeneration upon implantation. In the extrusion-based process, aqueous-based bioactive glass paste is deposited using a micro-sized nozzle. The fabricated green scaffolds are then heat treated to remove the binder. Because a major limitation of synthetic bone repair is insufficient vascularization in the interior of the porous implant, we conduct 3D bioprinting of mesenchymal stem cells (MSCs) suspended in the hydrogel and polymer-bioactive glass composite. Bioprinting a scaffold with these materials would offer a 3D environment for complex and dynamic interactions that govern the MSCs behavior in vivo. Bioactive glass is added to a mixture of polymer and organic solvent to make an extrudable paste. Porous polymer-glass composite scaffolds are fabricated by extruding this paste using a syringe, and MSCs suspended in the hydrogel is deposited using another syringe. In vitro assessment indicates the viability of the process to print MSCs suspended in Matrigel. Fluorescence images from the live-dead assay indicate that cells are alive and actively moving in the scaffold.



Publications
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“Bioprinting with Bioactive Glass Loaded Polylactic Acid Composite and Human Adipose Stem Cells,” K. C. R. Kolan, J. A. Semon, A. T. Bindbeutel, D. E. Day and M. C. Leu, Bioprinting, Vol. 18, June 2020.
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“3D-printed Biomimetic Bioactive Glass Scaffolds for Bone Regeneration in Rat Calvarial Defects,” K. C. R. Kolan, Y-W. Huang, J. A. Semon, and M. C. Leu, International Journal of Bioprinting, Apr. 2020.
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“Bioprinting with Human Stem Cells-Laden Alginate-Gelatin Bioink and Bioactive Glass for Tissue Engineering,” K. C. R. Kolan, J. A. Semon, B. Bromet, D. E. Day and M. C. Leu, International Journal of Bioprinting, Vo. 5, No. 2, 2019.
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“Near-field electrospinning of a polymer/bioactive glass composite to fabricate 3D biomimetic structures,” K. C. R. Kolan, J. Li, S. Roberts, J. A. Semon, J. Park, D. E. Day, and M. C. Leu, International Journal of Bioprinting, Vol. 5, No. 1, 2019.
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“Freeform extrusion fabrication of titanium fiber reinforced 13–93 bioactive glass scaffolds ,” Thomas, Albin, Krishna C.R. Kolan, Ming C. Leu, and Gregory E. Hilmas 69 (2017): 153-62.
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“3D bioprinting of stem cells and polymer/bioactive glass composite scaffolds for tissue engineering,” Murphy, Caroline, Krishna Kolan, Wenbin Li, Julie Semon, Delbert Day, and Ming Leu 3, no. 1 (2017): 1-11.
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“3D Printing of a Polymer Bioactive Glass Composite for Bone Repair,” Murphy, C, KCR Kolan, M Long, W Li, MC Leu, JA Semon, and DE Day, 2016.
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“Freeform Extrusion Fabrication of Titanium Fiber Reinforced Bioactive Glass Scaffolds,” Thomas, A., Krishna C. R. Kolan, M. C. Leu, and G. E. Hilmas, 2015.
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“In vitro assessment of laser sintered bioactive glass scaffolds with different pore geometries,” Kolan, Krishna C R, Albin Thomas, Ming C Leu, and Greg Hilmas 21, no. 2 (2015): 152-58.
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“The effects of 3D bioactive glass scaffolds and BMP-2 on bone formation in rat femoral critical size defects and adjacent bones,” Liu, Wai-Ching, Irina S Robu, Rikin Patel, Ming C Leu, Mariano Velez, and Tien-Min Gabriel Chu 9, no. 4 (2014).
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“Effect of architecture and porosity on mechanical properties of borate glass scaffolds made by selective laser sintering,” Kolan, Krishna CR, Ming C Leu, Gregory E Hilmas, and T Comte, 2013.
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“Effect of material, process parameters, and simulated body fluids on mechanical properties of 13-93 bioactive glass porous constructs made by selective laser sintering ,” Kolan, Krishna C.R., Ming C. Leu, Gregory E. Hilmas, and Mariano Velez 13 (2012): 14-24.
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“In Vivo Evaluation of 13-93 Bioactive Glass Scaffolds Made by Selective Laser Sintering (SLS),” Velez, M., S. Jung, K. C. R. Kolan, M. C. Leu, D.E. Day, and T-M.G. Chu, 237:91-99, 2012.
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“Freeze extrusion fabrication of 13-93 bioactive glass scaffolds for bone repair,” Doiphode, Tieshu, Nikhil D.and Huang, Ming C. Leu, Mohamed N. Rahaman, and Delbert E. Day 22, no. 3 (2011): 515-23.
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“Fabrication of 13-93 bioactive glass scaffolds for bone tissue engineering using indirect selective laser sintering,” Kolan, Krishna C R, Ming C Leu, Gregory E Hilmas, Roger F Brown, and Mariano Velez 3, no. 2 (2011).
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“Porous and strong bioactive glass (13–93) scaffolds fabricated by freeze extrusion technique,” Huang, T.S., M.N. Rahaman, N.D. Doiphode, M.C. Leu, B.S. Bal, D.E. Day, and X. Liu 31, no. 7 (2011): 1482-89.