title: A photoacoustic immunoassay for biomarker detection.
abstract: Challenges in protein biomarker analysis include insufficient sensitivity for detecting low-abundance biomarkers, poor measurement reproducibility, and the high costs and large footprints of detection systems. To address these issues, a new detection modality was developed for analyzing protein biomarkers based on the plasmon-enhanced photoacoustic (PA) effect. The detection modality employed a heterogeneous immunoassay scheme and used gold nanoparticles (AuNPs) as the signal reporter. Due to their localized plasmon resonance, AuNPs can strongly interact with intensity-modulated laser excitation and generate strong PA signals, which are subsequently sensed and quantified using a microphone. As an example, the performance of the PA immunoassay was evaluated by detecting the human interleukin 8 chemokine. The PA immunoassay provided approximately 143× lower limit of detection (LOD) than observed with the gold standard enzyme-linked immunosorbent assay - a decrease from 23pg/mL to 0.16pg/mL. In addition to the significant performance improvement in terms of the LOD, the PA immunoassay also offers advantages in terms of compatibility with low-cost instruments and the long-term stability of assay results.
authors.affiliation: Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Chemical and Biomolecule Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Mingfeng
authors.initials: M
authors.lastname: Cao
authors.affiliation: MTEC Photoacoustics Inc., 3507 Oakland St. Ames, IA 50014, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: McClelland
authors.affiliation: Department of Chemical and Biomolecule Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Zengyi
authors.initials: Z
authors.lastname: Shao
authors.affiliation: Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA; Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA. Electronic address: menglu@iastate.edu.
authors.forename: Meng
authors.initials: M
authors.lastname: Lu
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000652:urine; D004797:Enzyme-Linked Immunosorbent Assay; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D016209:Interleukin-8 / Q000032:analysis / Q000097:blood* / Q000652:urine*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D061088:Photoacoustic Techniques / Q000295:instrumentation*; D015203:Reproducibility of Results; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D015415:Biomarkers; D016209:Interleukin-8; D006046:Gold
keywords: Biomarker; ELISA; Human interleukin-8; Immunoassay; Nanoparticle; Photoacoustics; Surface plasmon resonance