Rapid Genotyping of Human Papillomavirus by Post-PCR Array-Based Hybridization Techniques

Kinetic hybridization measurements on a microarray are expected to become a valuable tool for genotyping applications. A method has been developed that enables kinetic hybridization measurements of PCR products on a low-density microarray. This is accomplished by pumping a solution containing PCR products up and down through a porous microarray substrate. After every pumping cycle, the fluorescently labeled PCR products hybridized to capture probes immobilized on the solid surface of the porous microarray substrate are measured. By this method, both binding curves and high-resolution melting curves are obtained instead of the single endpoint hybridization intensities as with commonly used post-PCR array-based hybridization techniques. We used 20 subtypes of the human papillomavirus (HPV) as a model system to test our detection method and blindly analyzed 216 clinical samples. We compared our microarray flowthrough method with a reference method, PCR followed by a reverse line blot (RLB). Real-time hybridization measurements followed by high-resolution melting curves of low concentrations of fluorescently labeled HPV targets on a microarray were successfully carried out without any additional chemical signal amplification. The results of our new method were in good agreement (93%, with a kappa coefficient of kappa = 0.88 [95% CI, 0.81 to 0.94]) with the RLB results. All discrepant samples were analyzed by a third method, enzyme immunoassay (EIA). Furthermore, in a number of cases, we were able to identify false-positive samples by making use of the information contained in the kinetic binding and melting curves. This clearly demonstrates the added value of the use of kinetic measurements and high-resolution melting curves, especially for highly homologous targets.