A new approach to revealing point mutations in DNA analyzed by colorimetric detection

Oligonucleotide probes containing polylysine residues for fabrication of DNA chips on various solid surfaces

Various materials, such as glass, plastic, metals, etc., are utilized for preparing DNA chips. In each particular case special approaches are used for immobilization of different oligonucleotide derivatives on the solid supports. We describe a general technique for DNA chips preparation on various unmodified surfaces using one type of oligonucleotide derivative, polylysine-oligonucleotide conjugates (PL-oligo). A long polyamine spacer in the PL-oligo conjugates provides a durable irreversible non-covalent immobilization onto a variety of solid supports and enough distance between oligonucleotides and the surface. The resulting DNA chips were shown to be useful for the detection of PCR DNA fragments and to be sensitive to single nucleotide discrepancies. They represent a promising instrument for revealing genetic diseases, genotyping viruses and bacteria, and for displaying their drug-resistant strains.