Bar
code assay for DNA
One probe is an iron oxide MMP, a magnetic iron oxide core with an amine-modified
silane coating, which was functionalized with alkanethiol-capped oligonucleotides
that are complementary to one 12-mer portion (5' ATTGATAAGGAT 3') of a target
sequence using a sulfosuccinimidyl 4-N-maleimidomethyl cyclohexane-1-carboxylate
(sulfo-SMCC) linker. The second probe is a gold NP (30nm) modified with two types
of oligonucleotides, one that is complementary to the target sequence of interest
(5' GGATTATTGTTAAAT 3') and different from the region recognized by the MMP,
and the other which is complementary to a bar-code sequence that is a unique
identification tag for the target sequence. The NPs are loaded with the target
binding and bar-code binding DNA by treating citrate-stabilized particles with
a solution containing the two alkyl-thiolcapped oligonucleotides at a 100:1 ratio.
