Determination of nucleic acid methylation

A method of determining the methylation status of a target nucleic acid molecule in a sample, wherein the method comprises the steps of:

• (a) bisulfate treatment of the sample for converting the unmethylated cytosine bases in the target nucleic acid molecule to uracil;
• (b) amplifying at least part of the converted target nucleic acid molecule, said part comprising a target region the methylation status of which is to be analyzed, in a polymerase chain reaction (PCR), using a pair of methylation-specific primers under conditions allowing such amplification to generate PCR amplification products (amplicons);
• (c) contacting the amplicons with a methylation-specific plasmonic nanoprobe comprising a plasmonic nanoparticle and a non-ionic oligonucleotide analog probe covalently coupled thereto, the oligonucleotide analog probe comprising a base sequence that is complementary to the target region, under conditions that allow the oligonucleotide analog probe and the amplicons comprising the target region to hybridize to each other, wherein the probe generates a detectable signal if hybridized to the target nucleic acid molecule that is distinguishable from the signal of the unhybridized probe;
• (d) determining the methylation status of the target nucleic acid molecule based on the determination of the melting temperature Tm of the hybrid of the nanoprobe and the target nucleic acid.