Silver-based grating structures for label-free biomolecule detection
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Date
2025
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Silver-based grating structures for biomolecule detection
Abstract
Addressing global healthcare challenges, including emerging diseases, antibiotic resistance, and environmental threats, requires innovative diagnostic tools. Biosensors based on label-free detection have gained attention for their rapid, sensitive, and cost-effective analysis. Among them, Surface Plasmon Resonance (SPR) stands out as a powerful technique for real-time biomolecular interaction monitoring. However, traditional prism-based SPR systems face limitations in integration and portability, spurring interest in grating-based alternatives.
This thesis explores the theoretical, computational, fabrication, and experimental aspects of grating-based SPR systems for label-free biosensing. It introduces key principles including surface plasmon polaritons (SPPs), and grating-coupling mechanisms. A literature review covers recent advances in plasmonic materials, microfabrication methods, and performance optimization.
Finite-Difference Time-Domain (FDTD) simulations are used to design grating structures, evaluate refractive index sensitivity, and validate results experimentally. Gratings are fabricated using electron beam lithography and deposition on Complementary Metal-Oxide-Semiconductor (CMOS)-compatible substrates, with microchannel integration enabling real-time biosensing. Experimental results show high sensitivity and strong agreement with simulation.
The study also investigates two-dimensional (2D) and gradient grating period (GGP) structures for multiplexed sensing and evaluates durability enhancements like protective coatings. Inverted gratings on glass offer environmental resilience but exhibit reduced coupling efficiency.
In summary, this work advances grating-based SPR sensor technology through modeling, fabrication, and experimental validation. The findings support their potential for compact, sensitive, and versatile biosensing, with future integration into semiconductor-based systems promising further miniaturization.
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Surface plasmon resonance, Nanotechnology, Microfabrication, Grating coupler, Label-free, Biosensors, Silver, Plasmonic material, Refractive index
Subjects based on RSWK
Biosensor