Annals of Biomedical Engineering

, Volume 45, Issue 2, pp 360–377 | Cite as

Optimizing Photo-Encapsulation Viability of Heart Valve Cell Types in 3D Printable Composite Hydrogels

  • Laura Hockaday Kang
  • Patrick A. Armstrong
  • Lauren Julia Lee
  • Bin Duan
  • Kevin Heeyong Kang
  • Jonathan Talbot Butcher
The Pursuit of Engineering the Ideal Heart Valve Replacement or Repair


Photocrosslinking hydrogel technologies are attractive for the biofabrication of cardiovascular soft tissues, but 3D printing success is dependent on multiple variables. In this study we systematically test variables associated with photocrosslinking hydrogels (photoinitiator type, photoinitiator concentration, and light intensity) for their effects on encapsulated cells in an extrusion 3D printable mixture of methacrylated gelatin/poly-ethylene glycol diacrylate/alginate (MEGEL/PEGDA3350/alginate). The fabrication conditions that produced desired hydrogel mechanical properties were compared against those that optimize aortic valve or mesenchymal stem cell viability. In the 3D hydrogel culture environment and fabrication setting studied, Irgacure can increase hydrogel stiffness with a lower proportional decrease in encapsulated cell viability compared to VA086. Human adipose derived mesenchymal stem cells (HADMSC) survived increasing photoinitiator concentrations in photo-encapsulation conditions better than aortic valve interstitial cells (HAVIC) and aortic valve sinus smooth muscle cells (HASSMC). Within the range of photo-encapsulation fabrication conditions tested with MEGEL/PEGDA/alginate (0.25–1.0% w/v VA086, 0.025–0.1% w/v Irgacure 2959, and 365 nm light intensity 2–136 mW/cm2), the highest viabilities achieved were 95, 93, and 93% live for HASSMC, HAVIC, and HADMSC respectively. These results identify parameter combinations that optimize cell viability during 3D printing for multiple cell types. These results also indicate that general oxidative stress is higher in photocrosslinking conditions that induce lower cell viability. However, suppressing this increase in intracellular oxidative stress did not improve cell viability, which suggests that other stress mechanisms also contribute.


Extrusion bioprinting Oxidative stress Mesenchymal stem cells Photo-polymerization Bio-ink Biofabrication 



CellTracker™ Red CMTPX


5-(and-6)-Chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate, acetyl ester CM-H2DCFDA


Compressive modulus calculated from 5 to 15% strain


Extracellular matrix


Human adipose derived mesenchymal stem cells


Human aortic valve sinus smooth muscle cells


Human aortic valve interstitial cells


Hank’s balanced salt solution


High powered light emitting diode

Irgacure 2959



Light emitting diode


Methacrylated gelatin


Phosphate buffered saline


Poly-ethylene glycol


Poly-ethylene glycol diacrylate


Three dimensional


Tissue engineered heart valves


Two dimensional







We thank Jhalak Agarwal and Jennifer Richards who helped develop hydrogel and cell handling protocols. We thank Shivaun Archer, Claudia Fischbach, Jennifer Puetzer, Jeffery Ballyns, Lawrence Bonassar, Paula Miller, Michael Shuler, and Sam Portnoff (Widetronix Inc.) for their assistance and sharing of equipment. We thank Luke and Naomi Shirk for providing porcine tissue for the mechanical testing. This research was supported by the Morgan Family, Felton Family Endowment for Human Heart Valve Research at Seattle Children’s Hospital, Hartwell Foundation, National Science Foundation (CBET-0955172), NSF Graduate Research Fellowship, and American Heart Association (AH0830384N and 13POST17220071).

Conflict of interest

No competing financial interests exist.

Supplementary material

10439_2016_1619_MOESM1_ESM.pdf (8.7 mb)
Supplementary material 1 (PDF 8896 kb)


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Copyright information

© Biomedical Engineering Society 2016

Authors and Affiliations

  • Laura Hockaday Kang
    • 1
  • Patrick A. Armstrong
    • 1
  • Lauren Julia Lee
    • 1
  • Bin Duan
    • 1
  • Kevin Heeyong Kang
    • 1
  • Jonathan Talbot Butcher
    • 1
    • 2
  1. 1.Nancy E. and Peter C. Meinig School of Biomedical EngineeringCornell UniversityIthacaUSA
  2. 2.Nancy E. and Peter C. Meinig School of Biomedical EngineeringCornell UniversityIthacaUSA

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