Pc. Pandey et Hh. Weetall, DETECTION OF AROMATIC-COMPOUNDS BASED ON DNA INTERCALATION USING AN EVANESCENT-WAVE BIOSENSOR, Analytical chemistry, 67(5), 1995, pp. 787-792
A now injection analysis system coupled with an evanescent wave biosen
sor employing total internal reflection of fluorescence radiation for
the detection of the compounds that intercalate within DNA is reported
. A highly fluorescent intercalator, ethidium bromide, has been used a
s the reference compound for the detection. The evanescent wave biosen
sor was developed using immobilized double-strand DNA (dsDNA) over the
surface of a cylindrical wave guide. The response of the DNA-modified
fiber is significantly higher than the response obtained with an unmo
dified fiber. The response of the biosensor at a constant concentratio
n of ethidium bromide increases on increasing the concentration of imm
obilized dsDNA. At the steady-state response of the biosensor, obtaine
d at a constant concentration of ethidium bromide, there is a decrease
in the response to the injection of another DNA intercalator that com
petes for the intercalation sites on the dsDNA, displacing the ethidiu
m bromide. This is immediately followed by recovery of the steady-stat
e response. The decrease in the sensor response is a linear function o
f the concentrations of injected intercalator. Response curves for 9,1
0-anthraquinone-2,6-disulfonic acid, remazol brillant blue, decacyclen
e, and 4',6-diamidino-2-phenylindole dihydrochloride are reported.