title: Use of Multiple Peptide-Based SERS Probes Binding to Different Epitopes on a Protein Biomarker To Improve Detection Sensitivity.
abstract: We propose an analytical strategy to improve the sensitivity for detecting a protein biomarker through signal multiplication by manipulating multiple peptide-based surface-enhanced Raman scattering (SERS) probes to bind the biomarker. Protective antigen (PA) was used as an Anthrax biomarker in this study. For this purpose, five small peptides selective to various PA epitopes with different binding affinities were chosen and peptide-conjugated Au nanoparticle (AuNP) SERS probes were individually prepared using each peptide. Initially, five different SERS probes were separately used to detect PA and the sensitivities were compared. Next, the possibility of enhancing sensitivity by employing multiple SERS probes was examined. Rather than applying the probes simultaneously, which would induce competitive binding, each probe was added sequentially and an optimal probe-addition sequence was determined to provide maximal sensitivity. Finally, PA samples at seven different concentrations were measured with the optimal sequence. The limit of detection (LOD) was 0.1 aM, and the enhancement was more effective at lower PA concentrations. The proposed scheme can be further applicable to detect other protein biomarkers to diagnose various diseases.
authors.affiliation: Department of Chemistry and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University , Seoul, 133-791, Korea.
authors.forename: Kayeong
authors.initials: K
authors.lastname: Shin
authors.affiliation: Department of Chemistry and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University , Seoul, 133-791, Korea.
authors.forename: Jun-Haeng
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Chemistry and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University , Seoul, 133-791, Korea.
authors.forename: Moon-Young
authors.initials: MY
authors.lastname: Yoon
authors.affiliation: Department of Chemistry and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University , Seoul, 133-791, Korea.
authors.forename: Hoeil
authors.initials: H
authors.lastname: Chung
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis* / Q000737:chemistry*; D001427:Bacterial Toxins / Q000032:analysis* / Q000737:chemistry*; D015415:Biomarkers / Q000032:analysis / Q000737:chemistry; D000939:Epitopes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D015335:Molecular Probes / Q000032:analysis / Q000737:chemistry; D010455:Peptides / Q000032:analysis* / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D015415:Biomarkers; D000939:Epitopes; D015335:Molecular Probes; D010455:Peptides; C030325:anthrax toxin; D006046:Gold