Fabrication of Top–Down-Based Optical Fiber Nanoprobes and Their Diagnostic Application for Pancreatic Cancer

Abstract

Top-down nanoparticle fabrication has been studied to improve reusability, durability, and reproducibility in bottom-up nanoparticle-based fiber-optic plasmonic sensors. Gold nanostructures were simply and inexpensively patterned onto optical fibers via nanosphere lithography. To compensate for their low sensitivity, a sandwich assay was incorporated. The nanotriangle and nanohole were characterized through refractive index sensing, which was also carried out in the bottom-up gold nanospheres. The immune responses for pancreatic cancer biomarker (carbohydrate antigen 19-9) were real-timely detected and compared in three structures. When a sandwich assay was applied to improve the detection limit, a lowest detection limit of 0.25 U/mL was achieved in the triangle-based plasmonic nanoprobe, which is approximately 700 times lower than the reference value. Based on these results, all the manufactured fiber-optic sensors were sufficiently applicable as biosensors. In particular, commercialization is expected as reliable and cost-effective devices in patterned nanostructures-based optrodes by upgrading sensitivity with sandwich immunoassay.