Pathogenic viruses are emerging contaminants in water which should be analyzed for water safety to preserve public health. A strategy was developed to quantify RNA and DNA viruses in parallel on chemiluminescence flow-through oligonucleotide microarrays. In order to show the proof of principle, bacteriophage MS2, ΦX174, and the human pathogenic adenovirus type 2 (hAdV2) were analyzed in spiked tap water samples on the analysis platform MCR 3. The chemiluminescence microarray imaging unit was equipped with a Peltier heater for a controlled heating of the flow cell. The efficiency and selectivity of DNA hybridization could be increased resulting in higher signal intensities and lower cross-reactivities of polymerase chain reaction (PCR) products from other viruses. The total analysis time for DNA/RNA extraction, cDNA synthesis for RNA viruses, polymerase chain reaction, single-strand separation, and oligonucleotide microarray analysis was performed in 4–4.5 h. The parallel quantification was possible in a concentration range of 9.6 × 105–1.4 × 1010 genomic units (GU)/mL for bacteriophage MS2, 1.4 × 105–3.7 × 108 GU/mL for bacteriophage ΦX174, and 6.5 × 103–1.2 × 105 for hAdV2, respectively, by using a measuring temperature of 40 °C. Detection limits could be calculated to 6.6 × 105 GU/mL for MS2, 5.3 × 103 GU/mL for ΦX174, and 1.5 × 102 GU/mL for hAdV2, respectively. Real samples of surface water and treated wastewater were tested. Generally, found concentrations of hAdV2, bacteriophage MS2, and ΦX174 were at the detection limit. Nevertheless, bacteriophages could be identified with similar results by means of quantitative PCR and oligonucleotide microarray analysis on the MCR 3.
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The authors like to thank the BMBF for financial support (project PATH2OGENSCAN, 02WU1142, 02WU1143, 02WU1144, 02WU1145) in the field of MCR 3 optimization. Especially we want to thank GWK Präzisionstechnik GmbH for their collaboration in the project and the supply of the MCR 3 research device for oligonucleotide microarray analysis. Also thanks to Huntsman Corporation (Rotterdam, the Netherlands) for the kindly provided free DAPEG samples.