Advances in DNA Detection on Paper Chips

Abstract: DNA detection has an increasing importance in our everyday lives, with applications ranging from microbial diagnostics to forensic analysis. Currently, as the associated costs decrease, DNA diagnostic techniques are routinely used not only in research laboratories, but also in clinical and forensic practice.The present thesis aims to unravel the potential of cellulose filter paper to be a viable candidate for DNA array support. There are two papers in this study. In Paper I, we studied the method of functionalizing the surface of filter paper and the possibility to detect DNA on acitve paper using fluorescence. In Paper II, we investigated visualization and throughput of DNA detection with magnetic beads on active filter papers, an assay which requires no instrumentation (scanner).The findings in Paper I show that XG-NH2 and PDITC can functionalize the cellulose filter paper and that the activated filter papers can covalently bind oligonucleotides modified with amino groups to detect DNA. The detection limit of the assay is approximately 0.2 pmol. In Paper II, visualization of DNA detection on active paper is achieved without instrumentation, based on the natural color of magnetic beads. Furthermore, successful multiplex detection supports the potential to increase the throughput of DNA detection on active papers.In summary, these studies show that active cellulose filter paper is a good DNA array support candidate as it provides a user-friendly and cost-efficient DNA detection assay. The methods described in Paper I and II are possible sources of development to a point-of-care device for on-site analysis of DNA contents in a sample.