Fiberoptic microneedle device facilitates volumetric infusate dispersion during convection-enhanced delivery in the brain

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Background and Objectives:

A fiberoptic microneedle device (FMD) was designed and fabricated for the purpose of enhancing the volumetric dispersal of macromolecules delivered to the brain through convection-enhanced delivery (CED) by concurrent delivery of sub-lethal photothermal hyperthermia. This study's objective was to demonstrate enhanced dispersal of fluid tracer molecules through co-delivery of 1,064 nm laser energy in an in vivo rodent model.

Materials and Methods:

FMDs capable of co-delivering fluids and laser energy through a single light-guiding capillary tube were fabricated. FMDs were stereotactically inserted symmetrically into both cerebral hemispheres of 16 anesthetized rats to a depth of 1.5 mm. Laser irradiation (1,064 nm) at 0 (control), 100, and 200 mW was administered concurrently with CED infusions of liposomal rhodamine (LR) or gadolinium–Evans blue-serum albumin conjugated complex (Gd–EBA) at a flow rate of 0.1 μl/min for 1 hour. Line pressures were monitored during the infusions. Rodents were sacrificed immediately following infusion and their brains were harvested, frozen, and serially cryosectioned for histopathologic and volumetric analyses.


Analysis by ANOVA methods demonstrated that co-delivery enhanced volumetric dispersal significantly, with measured volumes of 15.8 ± 0.6 mm3 for 100 mW compared to 10.0 ± 0.4 mm3 for its fluid only control and 18.0 ± 0.3 mm3 for 200 mW compared to 10.3 ± 0.7 mm3 for its fluid only control. Brains treated with 200 mW co-delivery exhibited thermal lesions, while 100 mW co-deliveries were associated with preservation of brain cytoarchitecture.


Both lethal and sub-lethal photothermal hyperthermia substantially increase the rate of volumetric dispersal in a 1 hour CED infusion. This suggests that the FMD co-delivery method could reduce infusion times and the number of catheter insertions into the brain during CED procedures. Lasers Surg. Med. 45:418–426, 2013. © 2013 Wiley Periodicals, Inc.

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