title: Quenching effect on gold nano-patterned cardiac troponin I chip by total internal reflection fluorescence microscopy.
abstract: Total internal reflection fluorescence microscopy (TIRFM) was investigated for enhanced detection sensitivity of cardiac troponin I (cTnI) on a gold nano-patterned protein chip. A 4×5 nanoarray patterning of a gold chip based on a single-molecule sandwich immunoassay was prepared with a spot diameter of 500 nm on glass substrates formed via electron-beam nanolithography. Quantitative trace analysis was possible as a function of increasing total internal reflection fluorescence intensity in the range of 84 aM-350 pM at prism-type and 35 aM-350 pM at objective-type TIRFM. Although using same gold nano-patterned cTnI chips, however, the objective-type TIRFM showed enhanced detection sensitivities 2.4 times better than the prism-type due to weaker gold quenching. This result is also about 7000 times lower in the detection limit compared with those obtained by conventional commercial sandwich enzyme-linked immunosorbent assay techniques.
authors.affiliation: Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Seungah
authors.initials: S
authors.lastname: Lee
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Kang
mesh_terms: D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D049329:Nanostructures / Q000737:chemistry*; D040081:Protein Array Analysis; D019210:Troponin I / Q000032:analysis*
chemical_list: D019210:Troponin I; D006046:Gold