Single base extension reaction-based surface enhanced Raman spectroscopy for DNA methylation assay

► We develop a DNA methylation assay based on single base extension reaction and SERS. ► Single base extension reaction offers high selectivity and specificity. ► Gold nanoparticle-induced SERS enhancement offers high sensitivity. ► This DNA methylation assay can achieve a detection limit of 3 pM. ► It can even distinguish as low as 1% methylation level from the mixtures.