Hybricomb. A novel diagnostic tool for DNA probing.

A technique is described in which unlabeled DNA probes are immobilized on the plastic surface of a 12-tooth comb and used to capture homologs by a hybridization procedure. In the examples described, cellular DNA from cervical biopsies is chemically labeled using the Chemi-probe system. The sample containing labeled DNA is then hybridized with the immobilized unlabeled probe (reverse hybridization). By means of this technique, human papillomavirus sequences can be detected with a sensitivity comparable to that of radioactive probe procedures. DNA hybrids are visualized as colored spots on each tooth by moving the comb through the reagent solutions of the prefilled developing plate. The whole procedure requires less than 50 minutes hands-on time, and the results are obtained in a few hours. Application of the technique to the detection and typing of mycoplasma DNA is also reported.