Selective release of a DNA oligomer hybridized to a microarray. (A) schematic of
the DNA array after hybridization with a FAM-labelledoligonucleotide; (B) FAM
and (C) Cy3 images of the surface; (D) schematic of the array after addition of
a Cy3-labeled release oligonucleotide containing a toehold complementary to the
fern sequence; (E) FAM and (F) Cy3 images taken after this exchange illustrating
that the replacement of the FAM sequence with the Cy3 release oligonucleotide
occurs only at features containing the designated toehold. The fern in panel E
(green, negative image) shows the absence of FAM-labelled target
oligonucleotide, while the fern in panel F (red, positive image) shows the
presence of the displacing Cy3-labeled release oligonucleotide. The fern
depicted in (E) and (F) is 9 mm in length and is comprised of individual DNA
features that are 14 × 14 μm in size. We have observed no
differences in elution efficiency from identical array features. Images (B),
(C), (E) and (F) were enhanced for visibility (contrast+40% and
brightness+40%).