Dissociation of double-stranded DNA by small metal nanoparticles.
The dissociation of double-stranded DNA (dsDNA) by 5 nm Au nanoparticles was observed through a series of DNA melting transition measurements. Experimental evidence implicates a strong non-specific interaction between the dsDNA and small Au nanoparticles as the cause. Subsequently the relative affinities of mononucleotides and polynucleotides for the 5 nm Au nanoparticle were determined by measuring the stability of mono- or polynucleotide-stabilized 5 nm Au nanoparticles in salt solutions of different concentrations as a function of time and temperature. The experimental data shows that for the mononucleotides, the affinity decreases in the following order: dA>dG>dC>dT. The order from the polynucleotides was however different, with the affinity decreasing as poly A approximately poly C approximately poly T>poly G. The lack of correlation between the two ranked orders indicates that the trend obtained from one cannot be used to infer the trend in the other, or vice versa. The evidence provided suggests that the persistence length of the oligonucleotides plays an important role, and must be considered alongside with the individual nucleotide binding strength to determine the overall interaction between the oligonucleotides and Au nanoparticles.
Yang
Jun
J
Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ont., Canada M5S 3M2. ju.yang@utoronto.ca
Pong
Boon-Kin
BK
Lee
Jim Yang
JY
Too
Heng-Phon
HP
D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009691:Nucleic Acid Denaturation; D013056:Spectrophotometry, Ultraviolet
D006046:Gold; D004247:DNA