title: Rapid isolation and detection of erythropoietin in blood plasma by magnetic core gold nanoparticles and portable Raman spectroscopy.
abstract: Isolating, purifying, and identifying proteins in complex biological matrices are often difficult, time consuming, and unreliable. Herein we describe a rapid screening technique for proteins in biological matrices that combines selective protein isolation with direct surface enhanced Raman spectroscopy (SERS) detection. Magnetic core gold nanoparticles were synthesized, characterized, and subsequently functionalized with recombinant human erythropoietin (rHuEPO)-specific antibody. The functionalized nanoparticles were used to capture rHuEPO from horse blood plasma within 15 min. The selective binding between the protein and the functionalized nanoparticles was monitored by SERS. The purified protein was then released from the nanoparticles' surface and directly spectroscopically identified on a commercial nanopillar SERS substrate. ELISA independently confirmed the SERS identification and quantified the released rHuEPO. Finally, the direct SERS detection of the extracted protein was successfully demonstrated for in-field screening by a handheld Raman spectrometer within 1 min sample measurement time.
  
  
  BACKGROUND
  The rapid detection of recombinant human erythropoietin (rHuEPO) is important in competitive sports to screen for doping offences. In this article, the authors reported their technique of direct surface enhanced Raman spectroscopy (SERS) detection using magnetic core gold nanoparticles functionalized with recombinant human erythropoietin-specific antibody. The findings should open a new way for future detection of other proteins.
authors.affiliation: Nanotechnology and Molecular Sciences Discipline, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Australia.
authors.forename: Roland
authors.initials: R
authors.lastname: Agoston
authors.affiliation: Nanotechnology and Molecular Sciences Discipline, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Australia. Electronic address: e.kiriakous@qut.edu.au.
authors.forename: Emad L
authors.initials: EL
authors.lastname: Izake
authors.affiliation: Nanotechnology and Molecular Sciences Discipline, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Australia. Electronic address: sivanesan.arumugam@qut.edu.au.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Sivanesan
authors.affiliation: Nanotechnology and Molecular Sciences Discipline, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Australia.
authors.forename: William B
authors.initials: WB
authors.lastname: Lott
authors.affiliation: Nanotechnology and Molecular Sciences Discipline, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, Australia.
authors.forename: Martin
authors.initials: M
authors.lastname: Sillence
authors.affiliation: Biological Research Unit, Racing Analytical Services Ltd., Melbourne, VIC, Australia.
authors.forename: Rohan
authors.initials: R
authors.lastname: Steel
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D004921:Erythropoietin / Q000097:blood* / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry*; D006736:Horses; D006801:Humans; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D059346:Magnets / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods
chemical_list: D055910:Antibodies, Immobilized; C554270:EPO protein, human; D058185:Magnetite Nanoparticles; D004921:Erythropoietin; D006046:Gold
keywords: Erythropoietin; In-field screening; Label-free SERS; Magnetic core gold nanoparticles; Proteins in biological fluids; Selective isolation