Assessment of Plasmonic Photothermal Therapy Through a Fiberoptic Microneedle Device for Pancreatic Cancer Treatment

Current clinical approaches for treating pancreatic cancer have been demonstrated as ineffective at improving midterm survival (<10%). Plasmonic photothermal therapy (PPTT) has been rarely explored as a treatment method for pancreatic cancer. Clinically used endoscopic ultrasound (EUS) can be coupled with a thin capillary fiberoptic for transferring light and gold nanoparticles to the targeted tissue volume for selective photothermal heating. PPTT requires knowledge of tissue specific thermal and optical properties. Literature review revealed a gap in such properties for pancreas tissue. To assess the proposed treatment, and to bridge the gap in the literature, a fiberoptic microneedle device (FMD) has been fabricated utilizing a silica based light guiding capillary through the fusion splice method. The optical, fluid, and mechanical characterization tests of FMD showed the high light coupling efficiency (~75%), maximum internal fluid pressure (~3MPa), and ability to penetrate a soft tissue phantom without tip buckling. Clinical EUS was used to investigate the benchtop optical visualization of FMD. Ex vivo porcine pancreas tissue was utilized to evaluate the thermal conductivity, light attenuation coefficient, absorption coefficient, and reduced scattering coefficient at 808 and 1064 nm laser wavelengths. Finally, the photothermal heating of ex vivo tissue was characterized by developing a computational model and implementing FMD for co-delivering variable light intensities and gold nanorod concentrations. These tests showed the effectiveness of PPTT in selective photothermal heating of tissue through manipulation of GNR concentration and light wavelengths.