Live imaging flow bioreactor for the simulation of articular cartilage regeneration after treatment with bioactive hydrogel

Assaf Bar, Emil Ruvinov, Smadar Cohen

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Osteochondral defects (OCDs) are conditions affecting both cartilage and the underlying bone. Since cartilage is not spontaneously regenerated, our group has recently developed a strategy of injecting bioactive alginate hydrogel into the defect for promoting endogenous regeneration of cartilage via presentation of affinity-bound transforming growth factor β1 (TGF-β1). As in vivo model systems often provide only limited insights as for the mechanism behind regeneration processes, here we describe a novel flow bioreactor for the in vitro modeling of the OCD microenvironment, designed to promote cell recruitment from the simulated bone marrow compartment into the hydrogel, under physiological flow conditions. Computational fluid dynamics modeling confirmed that the bioreactor operates in a relevant slow-flowing regime. Using a chemotaxis assay, it was shown that TGF-β1 does not affect human mesenchymal stem cell (hMSC) chemotaxis in 2D culture. Accessible through live imaging, the bioreactor enabled monitoring and discrimination between erosion rates and profiles of different alginate hydrogel compositions, using green fluorescent protein-expressing cells. Mathematical modeling of the erosion front progress kinetics predicted the erosion rate in the bioreactor up to 7 days postoperation. Using quantitative real-time polymerase chain reaction of early chondrogenic markers, the onset of chondrogenic differentiation in hMSCs was detected after 7 days in the bioreactor. In conclusion, the designed bioreactor presents multiple attributes, making it an optimal device for mechanistical studies, serving as an investigational tool for the screening of other biomaterial-based, tissue engineering strategies.

Original languageEnglish
Pages (from-to)2205-2216
Number of pages12
JournalBiotechnology and Bioengineering
Issue number9
StatePublished - 1 Sep 2018


  • affinity-binding
  • alginate hydrogel
  • bioreactor
  • chondrogenesis
  • transforming growth factor β1

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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