Abstract
Clinical treatment of Glioblastoma Multiforme (GBM) is generally ineffective in increasing patient survival. Convection-enhanced delivery (CED) is an alternative, investigative therapy in which a small caliber catheter is placed directly into the brain parenchyma. However, standard CED drug delivery techniques are unable to reach the entirety of the brain tumor, attributing to the failure of Phase III clinical trials. Fiber optic microneedle devices (FMDs), capable of simultaneous fluid and laser energy delivery, have shown potential to increase the drug dispersal volume when compared to fluid only devices. Previously described FMDs have had low laser transmission efficiency. In this work, we present two FMD manufacturing methods, a solid fiber inside capillary (SFIC) FMD and a modified fusion spliced (FS) FMD. Transmission efficiency of the two proposed FMDs were measured using a 1064 nm laser and an integrating sphere detector with air, deionized water, and black ink inside of the bore of the FMDs. The transmission efficiency of the FS FMD was between 45 and 127% larger than that of previously reported FS FMDs. Additionally, the transmission efficiency of the SFIC was significantly higher than the FS FMD (p ≤ 0.04 for all groups). However, the SFIC FMDs suffered catastrophic fracture failure at bend radii smaller than the manufacture specification, likely due to scribing of the capillary during the FMD fabrication process. Modifying FS FMDs appears to be the preferred fabrication method providing improved light transmission efficiency and mechanical strength on par with the capillary manufacturer’s specifications.
