Optically responsive nanoparticle layers for the label-free analysis of biospecific interactions in array formats.
A novel nanocomposite surface is prepared by coating surface-adsorbed dielectric colloidal particles with a contiguous layer of gold nanoparticles. The resulting surface shows pronounced optical extinction in reflection with the extinction peaks located in the UV-Vis and NIR region of the electromagnetic spectrum. The peak positions of these maxima change very sensitively with the adsorption of organic molecules onto the surface. For the adsorption of a monolayer of octadecanethiol, we observe a peak shift of 55 nm on average, which is about five times that of established label-free sensing methods based on propagating and localized surface plasmons. In a first proof-of-principle experiment, the interaction of peptides with specific antibodies has been detected without labeling by means of a fiber-optical set-up with microscopic lateral resolution. To avoid crosstalk in high-density arrays, the optically responsive surface areas can be locally separated on a micro- or even nanometer scale. Accordingly, the newly developed optically responsive surfaces are well suited for integration into high-density peptide or DNA arrays as demanded in genomics, proteomics, and biomedical research in general.
Dahint
Reiner
R
Applied Physical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany. Reiner.Dahint@urz.uni-heidelberg.de
Trileva
Elka
E
Acunman
Hatice
H
Konrad
Ulrike
U
Zimmer
Martin
M
Stadler
Volker
V
Himmelhaus
Michael
M
D015374:Biosensing Techniques / Q000379:methods*; D003429:Cross Reactions; D053768:Metal Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D055095:Optics and Photonics; D040081:Protein Array Analysis / Q000379:methods*; D020349:Surface Plasmon Resonance