Published online by Cambridge University Press: 01 February 2011
Encapsulation of PC12 cells (neural cell model) in alginate hydrogels with a protective coating of poly(lactic-co-glycolic acid) (PLGA) was achieved in the present study using co-axial electrospinning. Co-axial electrospinning consists of two concentric capillaries compared to only one capillary in conventional electrospinning. This allows for the processing of two liquid solutions simultaneously. Neural cells suspended in hydrogels were injected in the inner capillary, while the carbon nanotubes (added for conductivity) suspended in PLGA were injected in the outer capillary at controlled flow rates. On the application of a high voltage, a compound jet formed at the capillary exits and resulted in a co-electrospun fiber of nerve cells encapsulated in PLGA with carbon nanotubes. Carbon nanotubes were included to make the outer shell conductive to stimulate the PC12 cells. In this study, the voltage varied from 0 to 15 kV and various flow rates were tested to achieve a stable cone-jet mode in electrospinning. The cell density in the media varied from 0.5 to5 million cells/ml and the polymer solution (PLGA) concentration varied from 1 to 10 mg/ml. This resulted in a three dimensional conductive scaffold with nano-features (due to carbon nanotubes) on the polymer surface, which were collected on the grounded substrate. PC12 cells were found to be viable inside microspheres after 3 days. The size of the microspheres was quite uniform and less than 200 μm. This technique may be very useful for the development of cell encapsulated scaffolds which mimic natural body tissue organization for tissue engineering applications such as nervous system regeneration.