UV cross-linking of unmodified DNA on glass surfaces
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The performance of DNA microarrays strongly depends on their surface properties. Furthermore, the immobilization method of the capture molecules is of importance for the efficiency of the microarray in terms of sensitivity and specificity. This work describes the immobilization of single-stranded capture oligonucleotides by UV cross-linking on silanated (amino and epoxy) glass surfaces. Thereby we used amino (NH2) and poly thymine/poly cytosine modifications of the capture sequences as well as unmodified capture molecules. The results were compared to UV cross-linking of the same DNA oligonucleotides on unmodified glass surfaces. Immobilization and hybridization efficiency was demonstrated by fluorescence and enzyme-induced deposition of silver nanoparticles. We found out that single-stranded DNA molecules do not require a special modification to immobilize them by UV cross-linking on epoxy- or amino-modified glass surfaces. However, higher binding rates can be achieved when using amino-modified oligonucleotides on an epoxy surface. The limit of detection for the used settings was 5 pM.
KeywordsDNA microarray Enzyme-induced silver deposition UV cross-linking Silanated glass surfaces
Funding of research project “Jenaer Biochip Initiative” (JBCI) within the framework “Unternehmen Region—Inno Profile” from the Federal Ministry of Education and Research, Germany (BMBF) is gratefully acknowledged. This work was supported by the DFG (FR 1348/5-2).We thank Nanoprobes for the kind support with EnzMet® enhancement kit.
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