A novel bioreactor design for enhanced stem cells proliferation and differentiation in tissue engineered constructs

Recent studies have shown that culturing undifferentiated stem cells in appropriate biochemical environments and under me- chanical stimulation could provide the correct signals for cellular proliferation, differentiation and subsequent extracellular matrix production. This triggered a growing interest about in vitro bio- mechanically-stimulating culture environments.

The main goal of this work was to evaluate the efficacy of a newly developed bidirectional perfusion bioreactor. This apparatus en- ables implementing complex culturing programmes. Both perfusion flow rate and direction can be varied along the culturing period. This compact and user-friendly system is made of autoclavable materi- als enabling to culture up to 20 samples simultaneously. This study aimed at determining the most effective programmes for enhance- ment of cellular proliferation and differentiation. Fiber-bonded starch polycaprolactone (SPCL) meshes were statically seeded with goat bone marrow cells (GBMCs). These meshes were cultured ei- ther statically or under several dynamic culturing programmes for 7 and 14days. Collected samples were characterized by DNA and alkaline phosphatase (ALP) quantification and scanning electronic microscopy (SEM). DNA quantification results showed a tendency for greater cellular proliferation under static and unidirectional per- fusion conditions. ALP activity results revealed an enhanced cellular differentiation rate under cyclic flow direction inversion. SEM re- sults also showed greater cellular adherence and spreading in cell- scaffold hybrid constructs cultured under those conditions. In conclusion, this culture system can be used for enhancing cellular proliferation and differentiation by optimizing the combination of fluid flow rate and flow inversion frequency during culturing periods.