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Intravital three-dimensional bioprinting


Fabrication of three-dimensional (3D) structures and functional tissues directly in live animals would enable minimally invasive surgical techniques for organ repair or reconstruction. Here, we show that 3D cell-laden photosensitive polymer hydrogels can be bioprinted across and within tissues of live mice, using bio-orthogonal two-photon cycloaddition and crosslinking of the polymers at wavelengths longer than 850 nm. Such intravital 3D bioprinting—which does not create by-products and takes advantage of commonly available multiphoton microscopes for the accurate positioning and orientation of the bioprinted structures into specific anatomical sites—enables the fabrication of complex structures inside tissues of live mice, including the dermis, skeletal muscle and brain. We also show that intravital 3D bioprinting of donor-muscle-derived stem cells under the epimysium of hindlimb muscle in mice leads to the de novo formation of myofibres in the mice. Intravital 3D bioprinting could serve as an in vivo alternative to conventional bioprinting.

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Fig. 1: Intravital 3D bioprinting setup and in vivo application.
Fig. 2: Development of injectable HCC-conjugated polymers for i3D bioprinting application.
Fig. 3: Characterization of the photosensitive polymers.
Fig. 4: Three-dimensional objects of photosensitive gelatin hydrogels can be used for in vitro cell culture.
Fig. 5: HCC–gelatin hydrogels can be fabricated into pre-existing 3D environments and are suitable for 3D in vitro hSIO culture.
Fig. 6: Intravital 3D bioprinting.
Fig. 7: Cell-laden i3D bioprinting.

Data availability

The main data supporting the results in this study are available within the paper and its Supplementary Information. The raw image data and the analysed data generated in this study are available from the corresponding author upon reasonable request.


  1. 1.

    Kruth, J. P. Material incress manufacturing by rapid prototyping techniques. CIRP Ann. Manuf. Technol. 40, 603–614 (1991).

    Google Scholar 

  2. 2.

    Gross, B. C., Erkal, J. L., Lockwood, S. Y., Chen, C. & Spence, D. M. Evaluation of 3D printing and its potential impact on biotechnology and the chemical sciences. Anal. Chem. 86, 3240–3253 (2014).

    CAS  PubMed  Google Scholar 

  3. 3.

    Moroni, L. et al. Biofabrication strategies for 3D in vitro models and regenerative medicine. Nat. Rev. Mater. 3, 21–37 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  4. 4.

    Murphy, S. V. & Atala, A. 3D bioprinting of tissues and organs. Nat. Biotechnol. 32, 773–785 (2014).

    CAS  PubMed  Google Scholar 

  5. 5.

    Ong, C. S. et al. 3D bioprinting using stem cells. Pediatr. Res. 83, 223–231 (2018).

    CAS  PubMed  Google Scholar 

  6. 6.

    Kang, H. W. et al. A 3D bioprinting system to produce human-scale tissue constructs with structural integrity. Nat. Biotechnol. 34, 312–319 (2016).

    CAS  PubMed  Google Scholar 

  7. 7.

    Hong, N., Yang, G.-H., Lee, J. & Kim, G. 3D bioprinting and its in vivo applications. J. Biomed. Mater. Res. B 106, 444–459 (2018).

    CAS  Google Scholar 

  8. 8.

    Wang, M. et al. The trend towards in vivo bioprinting. Int. J. Bioprint. 1, 15–26 (2015).

    Google Scholar 

  9. 9.

    Skardal, A. et al. Bioprinted amniotic fluid-derived stem cells accelerate healing of large skin wounds. Stem Cells Transl. Med. 1, 792–802 (2012).

    CAS  PubMed  PubMed Central  Google Scholar 

  10. 10.

    Binder, K. W. et al. In situ bioprinting of the skin for burns. J. Am. Coll. Surg. 211, S76 (2010).

    Google Scholar 

  11. 11.

    Keriquel, V. et al. In situ printing of mesenchymal stromal cells, by laser-assisted bioprinting, for in vivo bone regeneration applications. Sci. Rep. 7, 1–10 (2017).

    CAS  Google Scholar 

  12. 12.

    Di Bella, C. et al. In situ handheld three-dimensional bioprinting for cartilage regeneration. J. Tissue Eng. Regen. Med 12, 611–621 (2018).

    CAS  PubMed  Google Scholar 

  13. 13.

    Wang, X., Rivera-Bolanos, N., Jiang, B. & Ameer, G. A. Advanced functional biomaterials for stem cell delivery in regenerative engineering and medicine. Adv. Funct. Mater. 29, 1–31 (2019).

    CAS  Google Scholar 

  14. 14.

    Zhang, Z., Wang, B., Hui, D., Qiu, J. & Wang, S. 3D bioprinting of soft materials-based regenerative vascular structures and tissues. Composites B 123, 279–291 (2017).

    CAS  Google Scholar 

  15. 15.

    Chin, S. Y. et al. Additive manufacturing of hydrogel-based materials for next-generation implantable medical devices. Sci. Robot. 2, eaah6451 (2017).

    Google Scholar 

  16. 16.

    Murphy, S. V., Skardal, A. & Atala, A. Evaluation of hydrogels for bio-printing applications. J. Biomed. Mater. Res. A 101, 272–284 (2013).

    PubMed  Google Scholar 

  17. 17.

    König, K. Multiphoton microscopy in life sciences. J. Microsc. 200, 83–104 (2000).

    PubMed  Google Scholar 

  18. 18.

    Chang, H., Shi, M., Sun, Y. & Jiang, J. Photo-dimerization characteristics of coumarin pendants within amphiphilic random copolymer micelles. Chin. J. Polym. Sci. 33, 1086–1095 (2015).

    CAS  Google Scholar 

  19. 19.

    Mahon, M. F., Raithby, P. R. & Sparkes, H. A. Investigation of the factors favouring solid state [2+2] cycloaddition reactions; the [2+2] cycloaddition reaction of coumarin-3-carboxylic acid. CrystEngComm 10, 573–576 (2008).

    CAS  Google Scholar 

  20. 20.

    Wang, D., Hou, X., Ma, B., Sun, Y. & Wang, J. UV and NIR dual-responsive self-assembly systems based on a novel coumarin derivative surfactant. Soft Matter 13, 6700–6708 (2017).

    CAS  PubMed  Google Scholar 

  21. 21.

    Belfield, K. D., Bondar, M. V., Liu, Y. & Przhonska, O. V. Photophysical and photochemical properties of 5,7-di- methoxycoumarin under one- and two-photon excitation. J. Phys. Org. Chem. 16, 69–78 (2002).

    Google Scholar 

  22. 22.

    Iliopoulos, K., Krupka, O., Gindre, D. & Salle, M. Reversible two-photon optical data storage in coumarin-based copolymers. J. Am. Chem. Soc. 132, 14343–14345 (2010).

    CAS  PubMed  Google Scholar 

  23. 23.

    Kim, S. H., Sun, Y., Kaplan, J. A., Grinstaff, M. W. & Parquette, J. R. Photo-crosslinking of a self-assembled coumarin-dipeptide hydrogel. N. J. Chem. 39, 3225–3228 (2015).

    CAS  Google Scholar 

  24. 24.

    Kabb, C. P., O’Bryan, C. S., Deng, C. C., Angelini, T. E. & Sumerlin, B. S. Photoreversible covalent hydrogels for soft-matter additive manufacturing. ACS Appl. Mater. Interfaces 10, 16793–16801 (2018).

    CAS  PubMed  Google Scholar 

  25. 25.

    Zhu, C. & Bettinger, C. J. Light-induced remodeling of physically crosslinked hydrogels using near-IR wavelengths. J. Mater. Chem. B 2, 1613–1618 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  26. 26.

    Azagarsamy, M. A., McKinnon, D. D., Alge, D. L. & Anseth, K. S. Coumarin-based photodegradable hydrogel: design, synthesis, gelation, and degradation kinetics. ACS Macro Lett. 3, 515–519 (2014).

    CAS  Google Scholar 

  27. 27.

    Williams, C. G., Malik, A. N., Kim, T. K., Manson, P. N. & Elisseeff, J. H. Variable cytocompatibility of six cell lines with photoinitiators used for polymerizing hydrogels and cell encapsulation. Biomaterials 26, 1211–1218 (2005).

    CAS  PubMed  Google Scholar 

  28. 28.

    Torgersen, J. et al. Hydrogels for two-photon polymerization: A toolbox for mimicking the extracellular matrix. Adv. Funct. Mater. 23, 4542–4554 (2013).

    CAS  Google Scholar 

  29. 29.

    Xing, J.-F., Zheng, M.-L. & Duan, X.-M. Two-photon polymerization microfabrication of hydrogels: an advanced 3D printing technology for tissue engineering and drug delivery. Chem. Soc. Rev. 44, 5031–5039 (2015).

    CAS  PubMed  Google Scholar 

  30. 30.

    Ingber, D. E. Cellular mechanotransduction: putting all the pieces together again. FASEB J. 20, 811–827 (2006).

    CAS  PubMed  Google Scholar 

  31. 31.

    Dupont, S. et al. Role of YAP/TAZ in mechanotransduction. Nature 474, 179–184 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  32. 32.

    Bian, L. et al. The influence of hyaluronic acid hydrogel crosslinking density and macromolecular diffusivity on human MSC chondrogenesis and hypertrophy. Biomaterials 34, 413–421 (2013).

    CAS  PubMed  Google Scholar 

  33. 33.

    Brigo, L. et al. 3D high-resolution two-photon crosslinked hydrogel structures for biological studies. Acta Biomater. 55, 373–384 (2017).

    CAS  PubMed  Google Scholar 

  34. 34.

    Lefort, C. A review of biomedical multiphoton microscopy and its laser sources. J. Phys. D 50, 423001 (2017).

    Google Scholar 

  35. 35.

    Ostrovidov, S. et al. Skeletal muscle tissue engineering: methods to form skeletal myotubes and their applications. Tissue Eng. B 20, 403–436 (2014).

    Google Scholar 

  36. 36.

    Moon, D. G., Christ, G., Stitzel, J. D., Atala, A. & Yoo, J J. Cyclic mechanical preconditioning improves engineered muscle contraction. Tissue Eng. A 14, 473–482 (2008).

    CAS  Google Scholar 

  37. 37.

    Gjorevski, N. et al. Designer matrices for intestinal stem cell and organoid culture. Nature 539, 560–564 (2016).

    CAS  PubMed  Google Scholar 

  38. 38.

    Morra, M. On the molecular basis of fouling resistance. J. Biomater. Sci. Polym. Ed. 11, 547–569 (2000).

    CAS  PubMed  Google Scholar 

  39. 39.

    Drumheller, P. D. & Hubbell, J. A. J. Densely crosslinked polymer networks of poly(ethylene glycol) in trimethylolpropane triacrylate for cell-adhesion-resistant surfaces. Biomed. Mater. Res. 29, 207–215 (1995).

    CAS  Google Scholar 

  40. 40.

    Gjorevski, N. & Lutolf, M. P. Synthesis and characterization of well-defined hydrogel matrices and their application to intestinal stem cell and organoid culture. Nat. Protoc. 12, 2263–2274 (2017).

    CAS  PubMed  Google Scholar 

  41. 41.

    Kominami, K. et al. The molecular mechanism of apoptosis upon caspase-8 activation: quantitative experimental validation of a mathematical model. Biochim. Biophys. Acta 1823, 1825–1840 (2012).

    CAS  PubMed  Google Scholar 

  42. 42.

    Tummers, B. & Green, D. R. Caspase-8; regulating life and death. Immunol. Rev. 277, 76–89 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  43. 43.

    Swartzlander, M. D., Lynn, A. D., Blakney, A. K., Kyriakides, T. R. & Bryant, S. J. Understanding the host response to cell-laden poly(ethylene glycol)-based hydrogels. Biomaterials 34, 952–964 (2013).

    CAS  PubMed  Google Scholar 

  44. 44.

    Qazi, T. H. et al. Cell therapy to improve regeneration of skeletal muscle injuries. J. Cachexia Sarcopenia Muscle 10, 501–516 (2019).

    PubMed  PubMed Central  Google Scholar 

  45. 45.

    Yin, H., Price, F. & Rudnicki, M. A. Satellite cells and the muscle stem cell niche. Physiol. Rev. 93, 23–67 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  46. 46.

    Cerletti, M. et al. Highly efficient, functional engraftment of skeletal muscle stem cells in dystrophic muscles. Cell 134, 37–47 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  47. 47.

    Rossi, C. A. et al. In vivo tissue engineering of functional skeletal muscle by freshly isolated satellite cells embedded in a photopolymerizable hydrogel. FASEB J. 25, 2296–2304 (2011).

    CAS  PubMed  Google Scholar 

  48. 48.

    Chapman, M. A., Meza, R. & Lieber, R. L. Skeletal muscle fibroblasts in health and disease. Differentiation 92, 108–115 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  49. 49.

    Mendias, C. L. Fibroblasts take the centre stage in human skeletal muscle regeneration. J. Physiol. 595, 5005 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  50. 50.

    Murphy, M. M., Lawson, J. A., Mathew, S. J., Hutcheson, D. A. & Kardon, G. Satellite cells, connective tissue fibroblasts and their interactions are crucial for muscle regeneration. Development 138, 3625–3637 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  51. 51.

    Urciuolo, A. et al. Decellularised skeletal muscles allow functional muscle regeneration by promoting host cell migration. Sci. Rep. 8, 8398 (2018).

    PubMed  PubMed Central  Google Scholar 

  52. 52.

    Rossi, G., Manfrin, A. & Lutolf, M. P. Progress and potential in organoid research. Nat. Rev. Genet. 19, 671–687 (2018).

    CAS  PubMed  Google Scholar 

  53. 53.

    Foster, A. A., Marquardt, L. M. & Heilshorn, S. C. The diverse roles of hydrogel mechanics in injectable stem cell transplantation. Curr. Opin. Chem. Eng. 15, 15–23 (2017).

    PubMed  Google Scholar 

  54. 54.

    Hoover, E. E. & Squier, J. A. Advances in multiphoton microscopy technology. Nat. Photonics 7, 93–101 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  55. 55.

    Horton, N. G. et al. In vivo three-photon microscopy of subcortical structures within an intact mouse brain. Nat. Photonics 7, 205–209 (2013).

    CAS  PubMed Central  Google Scholar 

  56. 56.

    Delrot, P., Loterie, D., Psaltis, D. & Moser, C. Single-photon three-dimensional microfabrication through a multimode optical fiber. Opt. Express 26, 1766–1778 (2018).

    CAS  PubMed  Google Scholar 

  57. 57.

    Chu, W. et al. Centimeter-height 3D printing with femtosecond laser two-photon polymerization. Adv. Mater. Technol. 3, 1700396 (2018).

    Google Scholar 

  58. 58.

    Schultz, S. R., Copeland, C. S., Foust, A. J., Quicke, P. & Schuck, R. Advances in two-photon scanning and scanless microscopy technologies for functional neural circuit imaging. Proc. IEEE Inst. Electr. Electron. Eng. 105, 139–157 (2017).

    CAS  PubMed  Google Scholar 

  59. 59.

    Horváth, O. P. Minimal invasive surgery. Acta Chir. Hung. 36, 130–131 (1997).

    PubMed  Google Scholar 

  60. 60.

    Palep, J. H. Robotic assisted minimally invasive surgery. J. Minim. Access Surg. 5, 1–7 (2009).

    PubMed  PubMed Central  Google Scholar 

  61. 61.

    Sims, G. E. C. & Snape, T. J. A method for the estimation of polyethylene glycol in plasma protein fractions. Anal. Biochem. 107, 60–63 (1980).

    CAS  PubMed  Google Scholar 

  62. 62.

    Habeeb, A. F. S. A. Determination of free amino groups in proteins by trinitrobenzenesulfonic acid. Anal. Biochem. 14, 328–336 (1966).

    CAS  PubMed  Google Scholar 

  63. 63.

    Natarajan, D. et al. Lentiviral labeling of mouse and human enteric nervous system stem cells for regenerative medicine studies. Neurogastroenterol. Motil. 26, 1513–1518 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  64. 64.

    Urcuiolo, A. et al. Collagen VI regulates satellite cell self-renewal and muscle regeneration. Nat. Commun. 4, 1964 (2013).

    Google Scholar 

  65. 65.

    Jung, P. et al. Isolation and in vitro expansion of human colonic stem cells. Nat. Med. 17, 1225–1227 (2011).

    CAS  PubMed  Google Scholar 

  66. 66.

    Sato, T. et al. Long-term expansion of epithelial organoids from human colon, adenoma, adenocarcinoma, and Barrett’s epithelium. Gastroenterology 141, 1762–1772 (2011).

    CAS  PubMed  PubMed Central  Google Scholar 

  67. 67.

    Ajduk, A., Biswas Shivhare, S. & Zernicka-Goetz, M. The basal position of nuclei is one pre-requisite for asymmetric cell divisions in the early mouse embryo. Dev. Biol. 392, 133–140 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

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This work was supported by 2017 STARS-WiC grant of University of Padova, Progetti di Eccellenza CaRiPaRo, TWINING of University of Padova, Oak Foundation Award (grant no. W1095/OCAY-14-191), ‘Consorzio per la Ricerca Sanitaria’ (CORIS) of the Veneto Region, Italy (LifeLab Program) to N.E. and the STARS Starting Grant 2017 of University of Padova (grant code LS3-19613) to A.U. P.D.C. is supported by the National Institute for Health Research (NIHR; grant no. NIHR-RP-2014-04-046). G.G.G. was supported by the NIHR Great Ormond Street Hospital Biomedical Research Centre Catalyst Fellowship. G.G.G., P.D.C. and N.E. were supported by the Oak award W1095/OCAY-14-191. All research at Great Ormond Street Hospital NHS Foundation Trust and University College London Great Ormond Street Institute of Child Health is made possible by the NIHR Great Ormond Street Hospital Biomedical Research Centre. The views expressed are those of the author(s) and not necessarily those of the National Health Service, the NIHR or the Department of Health. We thank D. Moulding for technical support and S. Schiaffino for scientific advice and discussion.

Author information




A.U. and N.E. designed the experiments. N.E. designed the photochemistry, I.P. synthesized and chemically characterized the coumarin polymers and S.S. contributed to the chemical characterization of coumarin polymers. A.U. performed and analysed in vitro and in vivo experiments. L.Brandolino. and P.R. contributed to in vitro experiments. V.S. contributed to the analysis of in vivo experiments. C.L. performed hydrogel injection into the brain and derived reporter cells and human ES cell-derived NSCs. G.G.G., E.Z., G.S. and M.M. contributed to organoid experiments. G.G. and P.D.C. characterized human intestinal organoid cultures. L.Brigo. contributed to the design and interpretation of in vitro two-photon crosslinking experiments. M.G. performed AFM analysis. A.U. and N.E. analysed the data and wrote the manuscript. N.E. supervised the project.

Corresponding author

Correspondence to Nicola Elvassore.

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Competing interests

N.E. has an equity stake in ONYEL Biotech s.r.l. A.U. and N.E. are submitting a patent for the intravital 3D bioprinting (provisional patent number 102020000008779).

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Supplementary information

Supplementary Information

Supplementary methods, figures, tables and video captions.

Reporting Summary

Supplementary Video 1

3D projection of z-stack images showing a ‘LIFE’-shaped HCC–4-arm PEG 3D structure related to Supplementary Fig. 12c.

Supplementary Video 2

3D reconstruction of z-stack images showing an empty cuboidal-shaped HCC–8-arm PEG 3D structure related to Supplementary Fig. 12e.

Supplementary Video 3

3D reconstruction of z-stack images showing a flower-shaped HCC–gel 3D structure related to Fig. 3d.

Supplementary Video 4

3D reconstruction of z-stack images showing the maximum fabrication depth related to Fig. 3e.

Supplementary Video 5

Orthogonal 3D reconstruction of z-stack images showing a cell-laden bioprinted structure related to Supplementary Fig. 18a.

Supplementary Video 6

Long-term 3D culture of MuSCs related to Fig. 4g.

Supplementary Video 7

3D reconstruction of z-stack images showing object fabricated into a drop of HCC–gel/Matrigel related to Fig. 5a.

Supplementary Video 8

3D reconstruction of z-stack images showing objects fabricated into a drop of HCC–gel/Matrigel in respect to hSIOs related to Supplementary Fig. 20a.

Supplementary Video 9

Intravital imaging related to Fig. 6b.

Supplementary Video 10

Intravital imaging related to Fig. 6e.

Supplementary Video 11

3D reconstruction related to Fig. 6e.

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Urciuolo, A., Poli, I., Brandolino, L. et al. Intravital three-dimensional bioprinting. Nat Biomed Eng 4, 901–915 (2020).

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