Abstract
Microcapsules with a range in 500-1000 µm in diameter have been used for mammalian cell-enclosing which have a potency to treat a wide range of diseases. Reduction in capsule diameter presents many advantages, including better cell oxygenation, higher mechanical strength, higher biocompatibility, smaller total implant volume, and accessibility to new implantation sites. The aim of the present study was to develop smaller mammalian cell-enclosing capsules with narrow distribution in size than those have been reported previously., i.e., less than 200 µm in diameter. The diameter of agarose capsules prepared in an immiscible coflowing liquid with laminar flow decreased with increasing the velocity of the ambient fluid flow and decreasing that of a agarose aqueous solution extruded from a nozzle with 300 µm in diameter. The mammalian cell-enclosing capsules of 76 ± 9 µm in diameter, i.e., subsieve-sized capsules, with narrow distribution in size were obtained by extruding the agarose solution at a velocity of 1.2 cm/sec into the ambient liquid paraffin flowing at a velocity of 20.8 cm/sec. The viability measurement based on the percentage of intact mitochondrial system in cell demonstrated that the reduction in diameter from 351 µm to 79.2 µm scarcely hindered the viability of the enclosed cells.
