title: Enhancing detection sensitivity of metallic nanostructures by resonant coupling mode and spectral integration analysis.
abstract: We report a simple method to efficiently improve the detection limit of surface plasmon resonance in periodic metallic nanostructures by using small angle illumination and spectral integration analysis. The large-area gold nanoslit arrays were fabricated by thermal-annealing template-stripping method with a slit width of 60 nm and period of 500 nm. The small angle illumination induced a resonant coupling between surface plasmon mode and substrate mode. It increased ~2.24 times intensity sensitivity at 5.5° incident angle. The small-angle illumination also resulted in multiple resonant peaks. The spectral integration method integrated all changes near the resonant peaks and increased the signal to noise ratio about 5 times as compared to single-wavelength intensity analysis. Combining both small angle and spectral integration, the detection limit was increased to one order of magnitude. The improvement of the detection limit for antigen-antibody interactions was demonstrated.
authors.forename: En-Hung
authors.initials: EH
authors.lastname: Lin
authors.forename: Wan-Shao
authors.initials: WS
authors.lastname: Tsai
authors.forename: Kuang-Li
authors.initials: KL
authors.lastname: Lee
authors.forename: Ming-Chang M
authors.initials: MC
authors.lastname: Lee
authors.forename: Pei-Kuen
authors.initials: PK
authors.lastname: Wei
mesh_terms: D000818:Animals; D000906:Antibodies / Q000378:metabolism; D000941:Antigens / Q000378:metabolism; D002417:Cattle; D008670:Metals / Q000737:chemistry*; D044085:Microfluidics; D049329:Nanostructures / Q000737:chemistry*; D012031:Refractometry; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013057:Spectrum Analysis / Q000379:methods*; D020349:Surface Plasmon Resonance
chemical_list: D000906:Antibodies; D000941:Antigens; D008670:Metals; D012710:Serum Albumin, Bovine