Sonia Abbasi Ravasjan - Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
Ghassem Amobediny - Research Center for New Technologies in Life Science Engineering, University of Tehran, Tehran, Iran
Mohammad Reza Hajat Aghaei - Research Center for New Technologies in Life Science Engineering, University of Tehran, Tehran, Iran.
Amir Esmaeili - School of chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran.

IntroductionRapid endothelialization is a prerequisite for developing small diameter blood vessel substitutes. An oxygen delivery system is required to provide suitable conditions for the metabolic activity of endothelial cells. Thus, bioreactors are required to supply nutrients (especially oxygen) for cell populations, and to apply mechanical stimulation to the cell matrix during culturing. Perfusion-based bioreactor systems are prevalent in vascular tissue engineering as they enhance cell growth, differentiation, and matrix production in vitro. For long-term cultivation of mammalian cells in a perfusion-based bioreactor, it is necessary to monitor the concentration of dissolved oxygen (DO) in the culture medium to ascertain the health of the cells.MethodsIn the present study, Nanofibrous PCL scaffolds were prepared by electrospinning method. Carboxylic groups were created on the surface of the scaffold using a NaOH solution (3M, 30min). Type one collagen was immobilized on the NaOH treated scaffolds. Human Umbilical Vein Endothelial Cells were seeded on the luminal surface of the collagen immobilized scaffolds and cultured under perfusion condition in a bioreactor up to 8 days. Furthermore, dissolved oxygen concentration was measured to estimate endothelial cells specific growth rate and doubling time in the bioreactor. Results and ConclusionOur results showed that metabolic activity of HUVECs cultured under static condition increased 2 times during 8 days of culture. In dynamic condition, metabolic activity of cells increased 4.5 times from third day up to eighth day of culture. The specific growth rate of the repopulation of endothelial cells on the electrospun scaffold and doubling time were measured to be 0.0453 h^-1 and 15.23h.

Bioreactors, Blood vessel substitutes, Endothelial cells, Electrospinning