title: Nanostar Clustering Improves the Sensitivity of Plasmonic Assays.
abstract: Star-shaped Au nanoparticles (Au nanostars, AuNS) have been developed to improve the plasmonic sensitivity, but their application has largely been limited to single-particle probes. We herein describe a AuNS clustering assay based on nanoscale self-assembly of multiple AuNS and which further increases detection sensitivity. We show that each cluster contains multiple nanogaps to concentrate electric fields, thereby amplifying the signal via plasmon coupling. Numerical simulation indicated that AuNS clusters assume up to 460-fold higher field density than Au nanosphere clusters of similar mass. The results were validated in model assays of protein biomarker detection. The AuNS clustering assay showed higher sensitivity than Au nanosphere. Minimizing the size of affinity ligand was found important to tightly confine electric fields and improve the sensitivity. The resulting assay is simple and fast and can be readily applied to point-of-care molecular detection schemes.
authors.affiliation: †Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States.
authors.forename: Yong Il
authors.initials: YI
authors.lastname: Park
authors.affiliation: †Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States.
authors.forename: Hyungsoon
authors.initials: H
authors.lastname: Im
authors.affiliation: †Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States.|‡Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, United States.
authors.forename: Ralph
authors.initials: R
authors.lastname: Weissleder
authors.affiliation: †Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States.
authors.forename: Hakho
authors.initials: H
authors.lastname: Lee
mesh_terms: D001681:Biological Assay / Q000379:methods*; D015374:Biosensing Techniques / Q000379:methods*; D004574:Electromagnetic Fields; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D057054:Molecular Imaging; D015335:Molecular Probes; D049329:Nanostructures / Q000737:chemistry*; D011506:Proteins / Q000032:analysis*
chemical_list: D015335:Molecular Probes; D011506:Proteins; D006046:Gold