title: Total internal reflection plasmonic scattering-based fluorescence-free nanoimmunosensor probe for ultra-sensitive detection of cancer antigen 125.
abstract: Highly sensitive detection of cancer antigen 125 (CA125) on nanoarray chips was carried out by means of total internal reflection (TIR) microscopy based on fluorescent labeling (i.e., TIR fluorescence microscopy; TIRFM) and fluorescent-free labeling (TIR scattering microscopy; TIRSM). TIR plasmonic scattering of nanoparticles (NPs) as a fluorescence-free immunosensor probe potentially superior to fluorescent probes was applied to quantify CA125 on a nanoarray chip. NP-labeled CA125 (NP-CA125) was immunoreacted on chips, and the TIR scattering illumination of NP-CA125 allowed quantitative TIRSM measurement of wavelength-dependent plasmonic scattering detection of CA125. In addition, Alexafluor 488-labeled CA125 was immunoreacted on the same chips for comparison of detection sensitivity. TIRSM showed less photobleaching and higher photostability and detection sensitivity than TIRFM, as well as a lower limit of detection (LOD), 0.0018U/mL. This LOD was ~144 times lower than that of previously reported detection methods. These results demonstrated that the wavelength-dependent TIR plasmon NPs can be used as an enhanced nanoimmunosensor probe, providing ultra-sensitive fluorescence-free biomolecule detection to enable earliest-stage disease diagnosis.
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
authors.forename: Suresh Kumar
authors.initials: SK
authors.lastname: Chakkarapani
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
authors.forename: Sujin
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Department of Chemistry, Graduate School, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea; Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea. Electronic address: shkang@khu.ac.kr.
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Kang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D018394:CA-125 Antigen / Q000097:blood*; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000295:instrumentation*; D012834:Silver / Q000737:chemistry*
chemical_list: D018394:CA-125 Antigen; D012834:Silver
keywords: Cancer antigen 125 (CA125); Nanoimmunosensor; Nanoparticle; TIR plasmonic scattering