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Engineering Nanoparticle Cluster Arrays for Bacterial Biosensing: The Role of the Building Block in Multiscale SERS Substrates
Author(s) -
Yang Linglu,
Yan Bo,
Premasiri W. Ranjith,
Ziegler Lawrence D.,
Negro Luca Dal,
Reinhard Björn M.
Publication year - 2010
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201000630
Subject(s) - materials science , nanoparticle , nanotechnology , surface enhanced raman spectroscopy , raman spectroscopy , noble metal , cluster (spacecraft) , biosensor , metal , raman scattering , optics , physics , computer science , metallurgy , programming language
Noble metal nanoparticle cluster arrays (NCAs) are a novel class of engineered substrates for surface enhanced Raman spectroscopy (SERS), in which the noble metal nanoparticles interact on multiple length scales to create a multiscale E‐field cascade enhancement. In this work the role of the building block for the NCA performance is quantified. Periodic NCAs with constant cluster diameter ( D = 200 nm) but variable nanoparticle diameter ( d ) and intercluster separation ( Λ ) were assembled on glass and their optical response and SERS enhancement were systematically characterized as a function of D , Λ , and d . An increase of d from 40 to 80 nm and simultaneous decrease of Λ from 200 to 50 nm led to an improvement of the ensemble averaged SERS enhancement factor by a factor of up to ∼8. The coefficient of variation ( c v ) of the enhancement factors ( G ) is significantly lower for the d = 80 nm NCAs than for the d = 40 nm and d = 60 nm NCAs. Optimized ( D = 200 nm, Λ = 50 nm, d = 80 nm) NCAs show the overall highest signal reproducibility of all investigated NCAs and random nanoparticle substrates and achieve effective single cell detection sensitivity.