Figure 3.

Using an array of differentially functionalized microrings, the identity of a particular SNP can be determined. Microrings were uniquely functionalized with one of four capture strands, each varying by only a single nucleotide at the same position within the sequence. Four different target sequences, each perfectly complementary to only one of the arrayed capture strands, were then individually flowed across the array and the desorption response monitored. In each case, the perfectly complementary interactions were observed as the slowest desorption rates within the column. By using an array of microring resonators it is therefore easy to not only establish that there is a SNP, but also precisely determine the identity of the mismatched nucleotide.