Localized surface plasmon resonance (LSPR) has emerged as one of the most sensitive, label-free biosensing techniques.  Traditional LSPR-based biosensing  utilizes the sensitivity of the plasmon frequency to changes in local index of refraction at the nanoparticle surface.1  Alternitavely, biosensing devices making use of plasmonic coupling hold promise of much greater sensitivity, specificity and resistence to biofouling.2  Here, we introduce the idea of carrying out biosensing with protein-nanoparticle arrays, in which the conformation of the protein mediates the plasmonic coupling of the nanoparticles attached.  Initial studies were carried out by binding small nanoparticles to collagen I fibrils.  Changes in solution conditions, such as pH, salt and sugar content, alter the structure of the collagen fibrils.  This then changes the spacing of the nanoparticles bound and produces changes in the LSPR frequency observed.  Our results show significant shifts in plasmonic frequency associated with both acid and salt titrations.  Characterization with transmission electron microscopy (TEM) shows that protein structure is indeed responsible for the changes in plasmonic frequency observed.  Through acid-mediated changes in collagen structure, these protein-nanoparticle plasmonic sensors show great potential in the sensitive detection of cancer cells. J. N. Anker , W. P. Hall , O. Lyandres , N. C. Shah , J. Zhao ,R. P. Van Duyne , Nat. Mater. 2008  , 7 , 442 � 453; L. B. Sagle, L. K. Ruvuna, J. A. Ruemmele, and R. P. Van Duyne, Nanomedicine 2011 , 6, 1447-1462.Jennifer I. L. Chen, Yeechi Chen, and David S. GingerJ. Am. Chem. Soc. 2010 , 28, 9600-9601.

Plasmonic sensing with protein-nanoparticle arrays

246th National Meeting (2013)

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