DNA-conjugated polymers for self-assembled DNA chip fabrication.
We developed two DNA-conjugated polymers, one based on polyallylamine and the other on polyacrylic acid, for use in DNA chips. A 30-mer single-stranded DNA probe and thioctic acid were covalently attached to polyallylamine as sidechains. The same single-stranded DNA and 3-(pyridyldithio)propionyl hydrazide were covalently attached to polyacrylic acid as sidechains. Both DNA-conjugated polymers could be specifically immobilized onto a gold sensor substrate by a self-assembly technique. The interactions between fully matched DNA and each DNA-conjugated polymer were investigated by surface plasmon resonance. A gold surface modified with either DNA-conjugated polymer recognized fully matched DNA much better than unmatched DNA. The hybridization selectivity and efficiency of DNA-conjugated polyallylamine was optimized by adjusting the pH so as to reduce the effects of cationic polymer sidechains. The hybridization selectivity and efficiency of DNA-conjugated polymers were higher than those of a conventional immobilized thiol-based DNA. The coating of DNA-conjugated polymers reduced nonspecific adsorption of DNA by the gold substrate. DNA-conjugated polyacrylic acid was more selective toward fully matched DNA than was DNA-conjugated polyallylamine. Therefore, DNA-conjugated polymers show promise for application in novel DNA chips.
Taira
Shu
S
Research Center of Advanced Bionics, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba 305-8562, Japan.
Yokoyama
Kenji
K
D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D011108:Polymers / Q000737:chemistry*; D020349:Surface Plasmon Resonance
D011108:Polymers; D004247:DNA