Kinetic discrimination of DNA single-​base mutations by localized surface plasmon resonance

Clinical application of DNA microarrays used for creening of single nucleotide polymorphisms (SNPs) are very important for diagnosis of diseases and appropriate treatment of patients. In this paper localized surface plasmon resonance (LSPR) technique has been used tostudy the DNA hybridization process for binary solutions of respectively perfectly matching (PM) and single base mismatching (MM) 93-mer ssDNAfrom KRAS codon 12. 5'-thiol modified 35-mer ssDNA has been linked to the Au nanodisks array as probe with a surface coverage of 2.8 + 0.1 x1012/cm2. Probe's binding properties was investigated in details,obtaining a sensitivity down to 10 nM and 13 nM, respectively for PM andMM, showing that the hybridization process occurs at a lower rate for MMwith respect to PM target. The competitive hybridization is accounted for by an inhibition model, where the non-complementary sequences kinetically hinder the hybridization of the perfect matching sequences, owing totheir above mentioned affinity constant differences for the same probe.Accordingly, the single nucleotide polymorphisms can therefore be revealed in a single step and label free mode with high sensitivity andspecificity by LSPR measurements.Suggested