Microfluidic direct writer with integrated declogging mechanism for fabricating cell-laden hydrogel constructs


Cell distribution and nutrient supply in 3D cell-laden hydrogel scaffolds are critical and should mimic the in vivo cellular environment, but been difficult to control with conventional fabrication methods. Here, we present a microfluidic direct writer (MFDW) to construct 3D cell-laden hydrogel structures with openings permitting media exchange. The MFDW comprises a monolithic microfluidic head, which delivers coaxial streams of cell-laden sodium alginate and calcium chloride solutions to form hydrogel fibers. Fiber diameter is controlled by adjusting the ratio of the volumetric flow rates. The MFDW head is mounted on a motorized stage, which is automatically controlled and moves at a speed synchronized with the speed of fiber fabrication. Head geometry, flow rates, and viscosity of the writing solutions were optimized to prevent the occurrence of curling and bulging. For continuous use, a highly reliable process is needed, which was accomplished with the integration of a declogging conduit supplying a solvent to dissolve the clogging gel. The MFDW was used for layer-by-layer fabrication of simple 3D structures with encapsulated cells. Assembly of 3D structures with distinct fibers is demonstrated by alternatively delivering two different alginate gel solutions. The MFDW head can be built rapidly and easily, and will allow 3D constructs for tissue engineering to be fabricated with multiple hydrogels and cell types.

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  1. M. Akbari, D. Sinton, M. Bahrami, Pressure drop in rectangular microchannels as compared with theory based on arbitrary cross section. J. Fluids Eng. 131, 041202 (2009)

  2. N. Annabi, A. Tamayol, J.A. Uquillas, M. Akbari, L. E. Bertassoni, C. Cha, G. Camci-Unal, M. R. Dokmeci, N. A. Peppas, A. Khademhosseini, 25th Anniversary Article: Rational design and applications of hydrogels in regenerative medicine. Advanced Materials. 26, 85–124 (2014)

  3. S. Arumuganathar, S. Irvine, J.R. McEwan, S.N. Jayasinghe, A novel direct aerodynamically assisted threading methodology for generating biologically viable microthreads encapsulating living primary cells. J. Appl. Polym. Sci. 107(2), 1215–1225 (2008)

  4. S.M. Berry, S.P. Warren, D.A. Hilgart, A.T. Schworer, S. Pabba, A.S. Gobin, R.W. Cohn, R.S. Keynton, Endothelial cell scaffolds generated by 3D direct writing of biodegradable polymer microfibers. Biomaterials 32(7), 1872–1879 (2011)

  5. E.J. Chung, M.J. Sugimoto, J. Koh, G. Ameer, Low pressure foaming: a novel method for the fabrication of porous scaffolds for tissue engineering. Tissue Eng. 18(2), 113–121 (2011)

  6. B.G. Chung, K.-H. Lee, A. Khademhosseini, S.-H. Lee, Microfluidic fabrication of microengineered hydrogels and their application in tissue engineering. Lab Chip 12(1), 45–59 (2012)

  7. V. Ellä, T. Annala, S. Länsman, M. Nurminen, M. Kellomäki, Knitted polylactide 96/4 L/D structures and scaffolds for tissue engineering. Biomatter 1(1), 102–113 (2012)

  8. N.E. Fedorovich, W. Schuurman, H.M. Wijnberg, H.-J. Prins, P.R. van Weeren, J. Malda, J. Alblas, W.J.A. Dhert, Biofabrication of osteochondral tissue equivalents by printing topologically defined, cell-laden hydrogel scaffolds. Tissue Eng. C 18(1), 33–44 (2012)

  9. R. Gaetani, P.A. Doevendans, C.H.G. Metz, J. Alblas, E. Messina, A. Giacomello, J.P.G. Sluijter, Cardiac tissue engineering using tissue printing technology and human cardiac progenitor cells. Biomaterials 33(6), 1782–1790 (2012)

  10. R. Gauvin, Y.C. Chen, J.W. Lee, P. Soman, P. Zorlutuna, J.W. Nichol, H. Bae, S. Chen, A. Khademhosseini, Microfabrication of complex porous tissue engineering scaffolds using 3D projection stereolithography. Biomaterials 33(15), 3824–3834 (2012)

  11. S. Ghorbanian, M.A. Qasaimeh, D. Juncker, Rapid prototyping of branched microfluidics in PDMS using capillaries. Chips and Tips (2010), Accessed 13 Feb 2014

  12. L.D. Harris, B.-S. Kim, D.J. Mooney, Open pore biodegradable matrices formed with gas foaming. J. Biomed. Mater. Res. 42(3), 396–402 (1998)

  13. M.-H. Ho, P.-Y. Kuo, H.-J. Hsieh, T.-Y. Hsien, L.-T. Hou, J.-Y. Lai, D.-M. Wang, Preparation of porous scaffolds by using freeze-extraction and freeze-gelation methods. Biomaterials 25(1), 129–138 (2004)

  14. S.J. Hollister, Porous scaffold design for tissue engineering. Nat. Mater. 4(7), 518–524 (2005)

  15. C.M. Hwang, A. Khademhosseini, Y. Park, K. Sun, S.-H. Lee, Microfluidic chip-based fabrication of PLGA microfiber scaffolds for tissue engineering. Langmuir 24(13), 6845–6851 (2008)

  16. C. Hwang, Y. Park, J. Park, K. Lee, K. Sun, A. Khademhosseini, S. Lee, Controlled cellular orientation on PLGA microfibers with defined diameters. Biomed. Microdevices 11(4), 739–746 (2009)

  17. E. Kang, G.S. Jeong, Y.Y. Choi, K.H. Lee, A. Khademhosseini, S.-H. Lee, Digitally tunable physicochemical coding of material composition and topography in continuous microfibres. Nat. Mater. 10, 877–883 (2011)

  18. K. Katoh, T. Tanabe, K. Yamauchi, Novel approach to fabricate keratin sponge scaffolds with controlled pore size and porosity. Biomaterials 25(18), 4255–4262 (2004)

  19. G.H. Kim, S.H. Ahn, H.J. Lee, S.Y. Lee, Y. Cho, W. Chun, A new hybrid scaffold using rapid prototyping and electrohydrodynamic direct writing for bone tissue regeneration. J. Mater. Chem. 21, 19138–19143 (2011)

  20. R. Landers, A. Pfister, U. Hübner, H. John, R. Schmelzeisen, R. Mülhaupt, Fabrication of soft tissue engineering scaffolds by means of rapid prototyping techniques. J. Mater. Sci. 37(15), 3107–3116 (2002)

  21. B.R. Lee, K.H. Lee, E. Kang, D.-S. Kim, S.-H. Lee, Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers. Biomicrofluidics 5(2), 022208 (2011a)

  22. G.-S. Lee, J.-H. Park, U.S. Shin, H.-W. Kim, Direct deposited porous scaffolds of calcium phosphate cement with alginate for drug delivery and bone tissue engineering. Acta Biomater. 7(8), 3178–3186 (2011b)

  23. L. Leng, A. McAllister, B. Zhang, M. Radisic, A. Günther, Mosaic hydrogels: one-step formation of multiscale soft materials. Adv. Mater. 24(27), 3650–3658 (2012)

  24. M.P. Lutolf, J.A. Hubbell, Synthetic biomaterials as instructive extracellular microenvironments for morphogenesis in tissue engineering. Nat. Biotechnol. 23(1), 47–55 (2005)

  25. S. Mazzitelli, L. Capretto, D. Carugo, X. Zhang, R. Piva, C. Nastruzzi, Optimised production of multifunctional microfibres by microfluidic chip technology for tissue engineering applications. Lab Chip 11, 1776–1785 (2011)

  26. G. Mazzoleni, D. Di Lorenzo, N. Steimberg, Modelling tissues in 3D: the next future of pharmaco-toxicology and food research? Genes Nutr. 4(1), 13–22 (2009)

  27. L. Moroni, J.R. de Wijn, C.A. van Blitterswijk, Integrating novel technologies to fabricate smart scaffolds. J. Biomater. Sci. Polym. Ed. 19(5), 543–572 (2008)

  28. F.T. Moutos, L.E. Freed, F. Guilak, A biomimetic three-dimensional woven composite scaffold for functional tissue engineering of cartilage. Nat. Mater. 6(2), 162–167 (2007)

  29. Y.S. Nam, T.G. Park, Biodegradable polymeric microcellular foams by modified thermally induced phase separation method. Biomaterials 20(19), 1783–1790 (1999)

  30. S.C. Neves, L.S. Moreira Teixeira, L. Moroni, R.L. Reis, C.A. Van Blitterswijk, N.M. Alves, M. Karperien, J.F. Mano, Chitosan/Poly(ɛ-caprolactone) blend scaffolds for cartilage repair. Biomaterials 32(4), 1068–1079 (2011)

  31. C. Norotte, F.S. Marga, L.E. Niklason, G. Forgacs, Scaffold-free vascular tissue engineering using bioprinting. Biomaterials 30(30), 5910–5917 (2009)

  32. H. Onoe, T. Okitsu, A. Itou, M. Kato-Negishi, R. Gojo, D. Kiriya, K. Sato, S. Miura, S. Iwanaga, K. Kuribayashi-Shigetomi, Y. Shimoyama, Y.T. Matsunaga, S. Takeuchi, Metre-long cell-laden microfibres exhibit tissue morphologies and functions. Nat. Mater. 12, 584–590 (2013)

  33. R. Opik, A. Hunt, A. Ristolainen, P.M. Aubin, M. Kruusmaa, Development of high fidelity liver and kidney phantom organs for use with robotic surgical systems Biomedical Robotics and Biomechatronics (BioRob), 2012 4th IEEE RAS & EMBS International Conference on (2012), pp. 425–430

  34. F. Pampaloni, E.G. Reynaud, E.H.K. Stelzer, The third dimension bridges the gap between cell culture and live tissue. Nat. Rev. Mol. Cell Biol. 8(10), 839–845 (2007)

  35. J.S. Park, D.G. Woo, B.K. Sun, H.-M. Chung, S.J. Im, Y.M. Choi, K. Park, K.M. Huh, K.-H. Park, In vitro and in vivo test of PEG/PCL-based hydrogel scaffold for cell delivery application. J. Control. Release 124(1–2), 51–59 (2007)

  36. C.M. Perrault, M.A. Qasaimeh, T. Brastaviceanu, K. Anderson, Y. Kabakibo, D. Juncker, Rev. Sci. Instrum. 81(11), 115107–115108 (2010)

  37. J.A. Rowley, D.J. Mooney, Alginate type and RGD density control myoblast phenotype. J. Biomed. Mater. Res. 60(2), 217–223 (2002)

  38. P. Schiavone, F. Chassat, T. Boudou, E. Promayon, F. Valdivia, Y. Payan, In vivo measurement of human brain elasticity using a light aspiration device. Med. Image Anal. 13(4), 673–678 (2009)

  39. Z. Shi, N. Chen, Y. Du, A. Khademhosseini, M. Alber, Stochastic model of self-assembly of cell-laden hydrogels. Phys. Rev. E 80(6), 061901 (2009)

  40. S.-J. Shin, J.-Y. Park, J.-Y. Lee, H. Park, Y.-D. Park, K.-B. Lee, C.-M. Whang, S.-H. Lee, “On the fly” continuous generation of alginate fibers using a microfluidic device. Langmuir 23(17), 9104–9108 (2007)

  41. A. Steinbuchel, Alginates: Biology and Applications (Springer, Germany, 2009)

  42. J. Sun, H. Tan, Alginate-based biomaterials for regenerative medicine applications. Materials 6(4), 1285–1309 (2013)

  43. A. Tamayol, M. Akbari, N. Annabi, A. Paul, A. Khademhosseini, D. Juncker, Fiber-based tissue engineering: Progress, challenges, and opportunities. Biotechnology Advances 31(5), 669–687 (2013)

  44. K.H. Tan, C.K. Chua, K.F. Leong, C.M. Cheah, W.S. Gui, W.S. Tan, F.E. Wiria, Selective laser sintering of biocompatible polymers for applications in tissue engineering. Biomed. Mater. Eng. 15(1), 113–124 (2005)

  45. L. Vogelaar, J.N. Barsema, C.J.M. van Rijn, W. Nijdam, M. Wessling, Phase separation micromolding—PSμM. Adv. Mater. 15(16), 1385–1389 (2003)

  46. X. Wang, W. Li, V. Kumar, A method for solvent-free fabrication of porous polymer using solid-state foaming and ultrasound for tissue engineering applications. Biomaterials 27(9), 1924–1929 (2006)

  47. F.E. Wiria, K.F. Leong, C.K. Chua, Y. Liu, Poly-ε-caprolactone/hydroxyapatite for tissue engineering scaffold fabrication via selective laser sintering. Acta Biomater. 3(1), 1–12 (2007)

  48. K.M. Yamada, E. Cukierman, Modeling tissue morphogenesis and cancer in 3D. Cell 130(4), 601–610 (2007)

  49. M. Yamada, S. Sugaya, Y. Naganuma, M. Seki, Microfluidic synthesis of chemically and physically anisotropic hydrogel microfibers for guided cell growth and networking. Soft Matter 8, 3122–3130 (2012)

  50. Y. Yokoyama, S. Hattori, C. Yoshikawa, Y. Yasuda, H. Koyama, T. Takato, H. Kobayashi, Novel wet electrospinning system for fabrication of spongiform nanofiber 3-dimensional fabric. Mater. Lett. 63(9–10), 754–756 (2009)

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We acknowledge funding from Natural Sciences and Engineering Research Council of Canada (NSERC), The Canadian Institutes of Health Research (CIHR), Certified Human Resources Professional (CHRP), Genome Canada, Genome Quebec, and Canada Foundation for Innovation (CFI.) M.A.Q. acknowledges Alexander Graham Bell Canada Graduate Scholarship (CGSD), M.A and A. T. acknowledge NSERC Postdoctoral fellowships, and D.J. acknowledges support from a Canada Research Chair. The authors thank Adiel Malik, Veronique Laforte, Sebastien Bergeron, and Kate Turner for critical reading of the manuscript.

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Ghorbanian, S., Qasaimeh, M.A., Akbari, M. et al. Microfluidic direct writer with integrated declogging mechanism for fabricating cell-laden hydrogel constructs. Biomed Microdevices 16, 387–395 (2014).

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  • Microfluidic coaxial flow
  • Direct writing
  • Cell-laden constructs
  • Calcium alginate
  • Tissue engineering
  • 3D cell scaffold