RAPID METHOD FOR VISUAL IDENTIFICATION OF SPECIFIC DNA-SEQUENCES BASED ON DNA-TAGGED LIPOSOMES

We describe a rapid method for visually determining specific DNA seque nces at femtomole concentrations. Liposomes, encapsulating a red dye a nd labeled with oligonucleotide, were used in a capillary migration-sa ndwich hybridization assay. Capture probe was immobilized on nitrocell ulose strips, and liposomes, migrating along each strip, formed a visu ally discernible band in the presence of target DNA. One femtomole of synthetic target sequence could be detected in <10 min. Sufficiently s tringent hybridization conditions can be used to allow the discriminat ion of a 10% mismatch sequence from perfectly complementary DNA. A 366 -base PCR product was detected at 200 fmol.