Tissue engineering hollow-fiber membrane bioreactors

Hollow-fiber membrane bioreactors for bone tissue engineering testing (Ye et al., 2004,... 

Hollow liber membranes are numerous small hollow fibers with semi-permeable walls, and are assembled within a cylindrical shell/jacket to function as a bioreactor. One of the clinical applications of hoUow fiber bioreactors is the hemodialyzer. These hollow fiber membranes are produced by solution-based processing method by solvent phase separation. This process has been used to produce filtration membranes in the past [11], and is now being used to produce tissue engineering scaffolds [12-14]. 

A similar approach to mimic capillary network and overcome diffusion limitations within large-tissue construct has been proposed by Narashima [23]. Hollow fiber membrane integrated within tissue-engineered scaffolds is supposed to supply required nutrients and gas through the walls of the fibers during in vitro perfusion bioreactor culture and then, being connected to the vasculature of the host, become a functional perfused network of the implant. 

Hollow fiber membranes (HFMs) formed via phase inversion methods exhibit specific physicochemical characteristics and generally favorable surface and mechanical properties. Due to these properties the HFMs can be used in diverse applications including ultrafiltration, gas separation, dialysis, cell culture, bioreactors, and tissue engineering. Most artificial kidneys are based on hollow fiber membranes. Blood is circulated through the center of the fiber, while isotonic saline, the dialysate, is pumped countercurrently around the outside of the fibers. Urea, creatinine, and other low-molecular weight metabolites in the blood diffuse across the fiber wall and are removed with the saline solution. 

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