Versatile derivatisation of solid support media for covalent bonding on DNA-microchips

A chemistry was developed that permits on DNA-arrays both the covalent immo bilisation of pre-fabricated nucleic acids-such as oligonucleotides, PCR-pr oducts or: peptide nucleic acid oligomers-and the in situ synthesis of such compounds on either glass or polypropylene surfaces. Bonding was found to be stable even after some 30 cycles of stripping. Due to a dendrimeric stru cture of the linker molecule, the loading can be modified in a controlled m anner and increased beyond the capacity of glass without negative effects o n hybridisation efficiency. Also, the chemistry warrants the modulation of other surface properties such as charge or hydrophobicity. Preferentially, attachment of nucleic acids takes place only via the terminal amino-group o f amino-modified oligonucleotides or the terminal hydroxyl-group of unmodif ied molecules so that the entire molecule-is accessible to probe hybridisat ion. This derivatisation represents a support chemistry versatile enough to serve nearly all current forms of DNA-arrays or microchips.