We have tested prototypes of a novel coaxial tube catheter in an in vitro gel model of cell delivery into the brain. Devices 1.6 and 2.0 mm outer diameter were used to deliver PC 12 cells (concentration = 106 cells ml−1) at 1 μl min−1 into a 5 ml sandwich of collagen and 0.1% agarose, with and without follow-on infusions of nerve growth factor (NGF). Post-infusion microscopic imaging (40X) at the infusion sites was then carried out over 7-day periods. The results showed that under these experimental conditions, it was possible to use these catheters to deliver cells without either leakage of trapped air into the gel or reflux of the cell suspension along the catheter insertion track. Differentiation of the NGF-treated cells was observed.