An abnormal resonance light scattering arising from ionic-liquid/DNA/ethidium interactions.
In the aqueous phase, ethidium bromide (EB) intercalates into the double helix structure of dsDNA (ds=double-stranded) with a notable enhancement in fluorescence and resonance light scattering (RLS). However, when dsDNA was extracted into an ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)), an abnormal RLS arising from the interactions of IL-DNA-EB was observed, with a substantial decrease of the recorded RLS. The cationic Bmim(+) groups of BmimPF(6) intercalate into the DNA helix structure, in which they interact with the P-O bonds of phosphate groups in DNA strands and result in a reduction of the base-pair interstice along with transformation of DNA conformations that consequently prohibits the intercalation of EB with DNA. Thus, in the IL phase, the interactions between ethidium and DNA were dominated by electrostatic interactions and hydrogen bonding, leading to a congregation of EB entities around the DNA strands that results in an increase of absorption by ethidium, and consequently the inner filter effect leads to a reduction of the RLS. The present observation has been applied to the direct quantification of DNA in an ionic-liquid phase after DNA from human whole blood was extracted into BmimPF(6).
Cheng
De-Hong
DH
Research Center for Analytical Sciences, Box 332, Northeastern University, Shenyang 110004, China.
Chen
Xu-Wei
XW
Wang
Jian-Hua
JH
Fang
Zhao-Lun
ZL
D004247:DNA / Q000097:blood* / Q000737:chemistry; D004996:Ethidium / Q000031:analogs & derivatives* / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry; D008027:Light; D009690:Nucleic Acid Conformation; D012542:Scattering, Radiation; D012996:Solutions / Q000737:chemistry; D014867:Water / Q000737:chemistry
C412621:1-butyl-3-methylimidazolium hexafluorophosphate; D007093:Imidazoles; D052578:Ionic Liquids; D012996:Solutions; C052890:ethidium-DNA complex; D014867:Water; D004247:DNA; D004996:Ethidium