Evaluation of locked nucleic acids for signal enhancement of oligonucleotide probes for microalgae immobilised on solid surfaces
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Biosensors and microarrays are powerful tools for species detection and monitoring of microorganisms. A reliable identification of microorganisms with probe-based methods requires highly specific and sensitive probes. The introduction of locked nucleic acid (LNA) promises an enhancement of specificity and sensitivity of molecular probes. In this study, we compared specificity and sensitivity of conventional probes and LNA modified probes in two different solid phase hybridisation methods: sandwich hybridisation on biosensors and on DNA microarrays. In combination with DNA-microarrays, the LNA probes displayed an enhancement of sensitivity, but also gave more false-positive signals. With the biosensor, the LNA probes showed neither signal enhancement nor discrimination of a single mismatch. In all cases, conventional DNA probes showed equal or better results than LNA probes. In conclusion, LNA technology may have great potential in methods that use probes in suspension and in gene expressions studies, but under certain solid surface-hybridisation applications, they do not improve signal intensity.
KeywordsLocked nucleic acids Oligonucleotide probes Microalgae Sandwich hybridisation Microarray
The authors would like to thank Annick Sawala (University of Durham, United Kingdom) for her assistance in the hybridisation experiments. The LNA probes were designed and provided by Exiqon A/S, Bygstubben 9, 2950 Vedbaek, Denmark and financed by the EU projects ALGADEC and FISH & CHIPS. Christine Gescher and Sonja Diercks were supported by the EU-projects FISH&CHIPS (GOCE-CT-2003-505491) and ALGADEC (COOP-CT-2004-508435-ALGADEC) of the 6th framework program of the European Union and the Alfred Wegener Institute for Polar and Marine Research.
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