Development of a Hollow-Core Fiberoptic Microneedle Device for the Treatment of Invasive Bladder Cancer

The hydraulic resistance characterization manuscript chronicles the early development of the hollow-core fiberoptic microneedle device (FMD). The study determined that for straight tubing with an inner bore of 150 μm and a length greater than 50 mm long, Poiseuille’s Law was shown to be accurate within 12% of experimental data for the pressure range of 69-517 kPa. Comparison between different needle design geometries indicated that tip diameters <55 μm cause a significant increase in hydraulic resistance. Tubing length should be kept to a minimum and tip diameter should be kept above this threshold to reduce overall hydraulic resistance. The bladder treatment study describes the fabrication and testing of the FMD for treatment of invasive urothelial cell carcinomas (UCCs). Experiments investigating the fluid dispersal of single-walled carbon nanohorns (SWNHs) in the wall of inflated, healthy ex vivo bladders demonstrated that perfusion of 2 cm 2 on the bladder wall’s surface can be achieved with a 5 minute infusion at 50 μL/min. Irradiation of the SWNH perfused bladder wall tissue with a free space, 1064 nm laser at an irradiance of 0.95 W/cm 2 for 40 seconds yielded a 480% temperature increase relative to similar irradiation of a non-infused control. Co-delivery experiments demonstrated both SWNH and light delivery though a single hollow-core fiber to heat the bladder wall 33 0C with an irradiance of 400 W/cm, demonstrating that the FMD can be used to achieve hyperthermia-based therapeutic effects via interstitial irradiation.