Biomedical Engineering Reference
In-Depth Information
FIGURE 3.8
(See. color. insert.). Modiied. non. cross-linking. colorimetric. detection. of. nucleic. acid. targets.. (A. and. B). AuNP.
functionalized.with.one.set.of.oligonucleotide.probe,.which.is.attached.to.the.AuNP.via.a.spacer.and.thiol.bond..
(C).In.the.presence.of.the.complementary.target.DNA,.hybridization.occurs..(D).In.the.absence.of.complementary.
target,.no.hybridization.occurs..(E).Upon.addition.of.NaCl,.the.solution.where.hybridization.occurred.remains.
red..This.is.because.the.hybridized.oligonucleotides.increase.the.negative.charge.of.AuNPs,.thereby.increasing.
their.resistance.to.aggregation..(F).In.the.solution.where.no.hybridization.occurred,.addition.of.NaCl.induces.
aggregation.of.AuNPs.by.neutralizing.their.negative.charge,.and.the.solution.color.changes.from.red.to.blue.
