Method of detecting a mutation in a target nucleic acid molecule in sample, comprising the steps of: (i) contacting a first conjugate comprising a first nanoparticle and a first oligonucleotide analog, wherein the first oligonucleotide analog is a phosphorodiamidate morpholino oligo or a derivative thereof that is covalently coupled to the first nanoparticle with a first aliquot of the sample containing the target nucleic acid sequence, wherein the first oligonucleotide analog comprises a base sequence that is complementary to the wildtype sequence of the target nucleic acid, under conditions which allow the first conjugate and the target nucleic acid molecule to hybridize to each other, to form a first conjugate:target nucleic acid molecule complex; (ii) contacting a second conjugate comprising a second nanoparticle and a second oligonucleotide analog, wherein the second oligonucleotide analog is a phosphorodiamidate morpholino oligo or a derivative thereof that is covalently coupled to the second nanoparticle with a second aliquot of the sample containing the target nucleic acid sequence, wherein the second oligonucleotide analog comprises a base sequence that is complementary to the mutated sequence of the target nucleic acid and differs from the base sequence of the first oligonucleotide analog by at least one nucleobase and wherein the first oligonucleotide analog and the second oligonucleotide analog have a sequence identity of at least 85%, under conditions which allow the second conjugate and the target nucleic acid molecule to hybridize to each other, to form a second conjugate:target nucleic acid molecule complex, and (iii) determining the melting temperatures T m of the complexes formed in the separate aliquots of the sample in steps (i) and (ii) and detecting whether said target nucleic acid molecule contains said mutation by comparing the T m of said complexes. (i) contacting a first conjugate comprising a first nanoparticle and a first oligonucleotide analog, wherein the first oligonucleotide analog is a phosphorodiamidate morpholino oligo or a derivative thereof that is covalently coupled to the first nanoparticle with a first aliquot of the sample containing the target nucleic acid sequence, wherein the first oligonucleotide analog comprises a base sequence that is complementary to the wildtype sequence of the target nucleic acid, under conditions which allow the first conjugate and the target nucleic acid molecule to hybridize to each other, to form a first conjugate:target nucleic acid molecule complex; (ii) contacting a second conjugate comprising a second nanoparticle and a second oligonucleotide analog, wherein the second oligonucleotide analog is a phosphorodiamidate morpholino oligo or a derivative thereof that is covalently coupled to the second nanoparticle with a second aliquot of the sample containing the target nucleic acid sequence, wherein the second oligonucleotide analog comprises a base sequence that is complementary to the mutated sequence of the target nucleic acid and differs from the base sequence of the first oligonucleotide analog by at least one nucleobase and wherein the first oligonucleotide analog and the second oligonucleotide analog have a sequence identity of at least 85%, under conditions which allow the second conjugate and the target nucleic acid molecule to hybridize to each other, to form a second conjugate:target nucleic acid molecule complex, and (iii) determining the melting temperatures T m of the complexes formed in the separate aliquots of the sample in steps (i) and (ii) and detecting whether said target nucleic acid molecule contains said mutation by comparing the T m of said complexes.