Ionic strength-controlled hybridization of KRAS single-nucleotides: A Surface Plasmon Resonance study

tThe discrimination of a fully matched, unlabeled KRAS wild-type (WT) (C-G) target sample with respectto three of the most frequent KRAS codon mutations (G12 S (C-A), G12 R (C-C), G12C (C-T)) was inves-tigated using an optimized detection strategy involving surface plasmon resonance (SPR), based onoptimized probe-surface density and ionic strength control. The changes observed in the SPR signal werealways larger for WT compared with the single-mismatch target DNA oligonucleotides, and were alignedwith the theoretical energy differences between the base pair C-G, C-T, C-A, C-C. Hybridization rates of∼106M−1s−1were detected without the introduction of high temperature and labels, usually neededin conventional hybridization methods. One hundred percent mutation discrimination of the matchedKRAS wild-type (C-G) sequence with respect to three mismatched G12C (C-T), G12 S (C-A), G12 R (C-C)target sequences was achieved.