Dendrimer-Functionalized Self-Assembled Monolayers as a Surface Plasmon Resonance Sensor Surface

We report here a multistep route for the immobilization of DNA and proteins on chemically modified gold substrates using fourth-generation NH2-terminated poly(amidoamine) dendrimers supported by an underlying amino undecanethiol (AUT) self-assembled monolayer (SAM). Bioactive ultrathin organic films...

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Bibliographic Details
Published in:	Langmuir Vol. 20; no. 16; pp. 6808 - 6817
Main Authors:	Mark, Sonny S, Sandhyarani, Neelakantapillai, Zhu, Changcheng, Campagnolo, Christine, Batt, Carl A
Format:	Journal Article
Language:	English
Published:	United States American Chemical Society 03-08-2004
Subjects:	Biosensing Techniques - methods Dendrimers - chemistry DNA - chemistry Gold - chemistry Immobilization Membranes, Artificial Microscopy, Atomic Force - methods Microscopy, Fluorescence - methods Polyamines - chemistry Proteins - chemistry Sensitivity and Specificity Spectrometry, X-Ray Emission - methods Spectrophotometry, Ultraviolet - methods Spectroscopy, Fourier Transform Infrared - methods Sulfhydryl Compounds - chemistry Surface Plasmon Resonance - methods Surface Properties Time Factors
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Summary:	We report here a multistep route for the immobilization of DNA and proteins on chemically modified gold substrates using fourth-generation NH2-terminated poly(amidoamine) dendrimers supported by an underlying amino undecanethiol (AUT) self-assembled monolayer (SAM). Bioactive ultrathin organic films were prepared via layer-by-layer self-assembly methods and characterized by fluorescence microscopy, variable angle spectroscopic ellipsometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and attenuated total internal reflection Fourier transform infrared spectroscopy (ATR-FTIR). The thickness of the AUT SAM base layer on the gold substrates was determined to be 1.3 nm from ellipsometry. Fluorescence microscopy and AFM measurements, in combination with analyses of the XPS/ATR-FTIR spectra, confirmed the presence of the dendrimer/biopolymer molecules on the multilayer sensor surfaces. Model proteins, including streptavidin and rabbit immunoglobulin proteins, were covalently attached to the dendrimer layer using linear cross-linking reagents. Through surface plasmon resonance measurements, we found that sensor surfaces containing a dendrimer layer displayed an increased protein immobilization capacity, compared to AUT SAM sensor surfaces without dendrimer molecules. Other SPR studies also revealed that the dendrimer-based surfaces are useful for the sensitive and specific detection of DNA−DNA interactions. Significantly, the multicomponent films displayed a high level of stability during repeated regeneration and hybridization cycles, and the kinetics of the DNA−DNA hybridization process did not appear to be influenced by surface mass transport limiting effects.
Bibliography:	ark:/67375/TPS-5J31GVWJ-L istex:1D7B499F740E867C1A7D0F8D93CE9E078C545077 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0743-7463 1520-5827
DOI:	10.1021/la0495276