Research Interests

We are developing biologically-engineered “off-the-shelf” vascular grafts, heart valves, and vein valves. What is particularly exciting is that we have shown our material, produced by skin cells (fibroblasts), has the capacity to grow (Nature Comms, 2016) and may thus transform the treatment of pediatric congenital heart defects. The material is fabricated from entrapping fibroblasts in a biopolymer (fibrin) gel and constraining the cell-mediated gel compaction to create fibrin alignment. Bioreactors are used to create circumferentially-aligned tubes by stimulating the cells to replace the aligned fibrin with an aligned collagenous matrix, and these tubes can then be used as vascular grafts and tubular heart valves for surgical implantation. Upon decellularization, they become “off-the-shelf” non-immunogenic vessel and valve replacements that are conducive to recellularization by the host, leading to their growth capacity. Engineered human cardiac tissue that beats via entrapped iPSC-cardiomyocytes and contains a co-aligned self-assembled microvessel network has also been created in our lab using the same approach.
Our current research focuses creating transcatheter heart valves and vein valves, combining our unique tubes of cell-produced matrix with stent technology by growing the matrix tube directly on the stent, and conferring immediate or rapid hemocompatibility of the matrix using autologous stem cell and small molecule strategies.
Contact guidance -- the ability of cells to sense and aligned with aligned fibers -- is crucial to our ability to create tissues with prescribed alignment, such as the circumferentially-aligned tubes. The signal presented by aligned fibrils that cells actually sense is a longstanding open question being investigated using unique methods, including magnetic alignment and photo-crosslinking of fibrin, to systematically vary the chemical/physical signals that cells might be sensing.


  • Distinguished McKnight University Professor
  • Fellow of the Biomedical Engineering Society
  • Fellow of the American Institute for Medical and Biological Engineering
  • College Student Board Outstanding Professor in Biomedical Engineering
  • Shell Land Grant Chair in Chemical Engineering & Materials Science
  • NSF Presidential Young Investigator
  • McKnight-Land Grant Professor

Selected Publications

  • A cardiac patch from aligned microvessel and cardiomyocyte patches,” Schaefer, J.A., Guzman, P.A., Riemenschneider, S.B., Kamp, T.J. and R.T. Tranquillo, J Tissue Eng Regen Med 12:546-566 (2018).
  • Implantation of a tissue-engineered tubular heart valve in growing lambs,” Reimer, J.M., Syedain, Z.H., Haynie, B., Lahti, M., Berry, J. and R. T. Tranquillo, Ann Biomed Eng 5: 439-451 (2017).
  • A completely biological ‘off-the-shelf’ arteriovenous graft that recellularizes in baboons,” Syedain, Z.H., Graham, M.L., Dunn, T.B., O’Brien, T., Johnson, S.L., Schumacher, R.J. and R. T. Tranquillo, Science Transl Med 9(414): 10.1126/scitranslmed.aan4209 (2017).
  • Tissue engineering of acellular vascular grafts capable of somatic growth in young lambs Syedain, Z.H., Reimer, J. M., Lahti, M., Berry, J., and R.T. Tranquillo Nat Comm (in press).
  • Cyclic stretch and perfusion bioreactor for conditioning large diameter engineered tissue tubes Schmidt, J.B. and R.T. Tranquillo Ann Biomed Eng 44(5):1785-97 (2016).
  • 6-month aortic valve implantation of an off-the-shelf tissue-engineered valve in sheep Syedain, Z.H., Reimer, J.M., Schmidt, J.B., Lahti, M., Berry, J., Bianco, R. and R.T. Tranquillo Biomaterials 73:175-84 (2015).
  • Inosculation and perfusion of pre-vascularized tissue patches containing aligned human microvessels after myocardial infarction Riemenschneider, S.B., Mattia, D.J., Wendel, J.S., Schaefer, J.A., Ye, L., Guzman, P.A., and R.T. Tranquillo Biomaterials 97:51-61 (2016).
  • Tissue contraction force microscopy for optimization of engineered cardiac tissue Schaefer, J.A. and R.T. Tranquillo Tissue Eng Part C 22:76-83 (2016).
  • Functional effects of a tissue-engineered cardiac patch from human induced pluripotent stem cell-derived cardiomyocytes in a rat infarct model Wendel, J., Ye, L., Rao, T. Zhang, J., Zhang, J., Kamp, T.J. and R.T. Tranquillo STEM CELLS Transl Med 4:1324-32 (2015).
  • Effects of intermittent and incremental cyclic stretch on ERK signaling and collagen production in engineered tissue Schmidt, J.B. and R.T. Tranquillo Cell Molec Bioeng 9:55-64 (2015).
  • Automated image analysis programs for the quantification of microvascular network characteristics Morin, K.T., Carlson, P. C. and R. T. Tranquillo Methods 84: 76-83 (2015).
  • Pediatric tubular pulmonary heart valve from decellularized engineered tissue tubes Reimer, J.M., Syedain, Z.H., Haynie, B and R.T. Tranquillo Biomaterials 62: 88-94 (2015).
  • Influence of culture conditions and extracellular matrix alignment on human mesenchymal stem cell invasion into decellularized engineered tissues Weidenhamer, N.K., Moore, D.L., Lobo, F.L., Klair, N.T. and R.T. Tranquillo J Tissue Eng Regen Med 9: 605-18 (2015).
  • A mathematical model for understanding fluid flow through engineered tissues containing microvessels Morin, K.T., Lenz, M.S., Labat, C. and R.T. Tranquillo J Biomech Eng 137: 051003 (2015).
  • Engineered microvessels possessing alignment and high lumen density via cell-induced fibrin gel compaction and interstitial flow Morin, K.T., Dries-Devlin, J.L. and R.T. Tranquillo Tissue Eng Part A 20: 553-65 (2014).
  • Shelf-life of bioprosthetic heart valves: a structural and mechanical study
Bob Tranquillo - Headshot


Phone: 612/625-6868

Office: 220 Amundson Hall

Research Group

Support Bob Tranquillo's Research

  • B.S., Chemical Engineering, Pennsylvania State University, 1979
  • M.S., Chemical Engineering, Stanford University, 1980
  • Ph.D., Chemical Engineering, University of Pennsylvania, 1986
  • NATO Postdoctoral Fellow, Oxford, 1986-87