| AVS 60th International Symposium and Exhibition | |
| Biomaterial Interfaces | Thursday Sessions |
| Session BI+NL+NS+SS-ThM |
| Session: | Bio/Nano Interfaces |
| Presenter: | R. Dahint, University of Heidelberg, Germany |
| Authors: | H.O. Guvenc, University of Heidelberg, Germany C. Schirwitz, Karlsruhe Institute of Technology, Germany F. Breitling, Karlsruhe Institute of Technology, Germany F.R. Bischoff, German Cancer Research Center Heidelberg, Germany A. Nesterov-Mueller, Karlsruhe Institute of Technology, Germany V. Stadler, PEPperPRINT GmbH, Heidelberg, Germany J. Wagner, University of Heidelberg, Germany R. Dahint, University of Heidelberg, Germany |
| Correspondent: | Click to Email |
The detailed analysis of biospecific interactions is of crucial importance in biomedicine, biotechnology, and pharmacology.Important applications range from medical diagnosis and drug development to the screening of the human genome and proteome. In recent years, array concepts have become very popular and powerful tools to allow for highly parallel, rapid identification of binding events. These arrays contain a multitude of different probe molecules immobilized at specific locations of an underlying substrate.
Interaction analysis is usually facilitated by labelling the potential binding partners with additional markers. Today, many of such techniques are well-established yielding considerably low detection limits and high lateral resolution. Yet, they suffer from the fact that labelling procedures are usually costly and time-consuming, that the labelling efficiency needs to be properly controlled for quantitative analysis, and that the marker itself can affect the original functionality of the molecules being studied. Moreover, the detection of low-affinity binding events is often hampered as additional washing steps and (bio)chemical reactions are required in-between the interaction and detection processes. To overcome those obstacles, strong efforts have been made to establish label-free detection schemes for interaction analysis. However, marker-free, sensitive readout of high-density arrays is still a technological challenge.
Here we report recent experiments on the label-free detection of protein/peptide interactions in complex arrays based on surface plasmon imaging with core-shell nanoparticle monolayers. Upon reflection of white light, these films exhibit a pronounced extinction spectrum which shifts to higher wavelength upon molecule binding, thus, providing a simple, sensitive and label-free detection mechanism. Variants of HA (human influenza hemagglutinin A) and FLAG epitopes with permuted amino acid sequence are synthesized in array format by means of combinatorial chemistry using a novel laser printing approach. After array preparation, the pattern is cleaved from the carrier and transferred to a biosensor surface consisting of core-shell nanoparticle films. By this means, the arrays are purified from synthesis artefacts caused by incomplete coupling reactions in the synthesis without the loss of spatial resolution. The interaction of the different peptides with their respective antibodies is quantified by the wavelength shift observed for individual peptide spots and compared to fluorescence-based interaction analysis. Based on the data we conclude on relevant amino acid sequences for an efficient antibody/epitope binding.