Dimeric gold nanoparticle assembly for detection and discrimination of single nucleotide mutation in Duchenne muscular dystrophy

Nanoparticles are increasingly being used for applications in clinical diagnostics due to their unique physical and chemical properties. Gold nanoparticles, in particular, have unique optical properties allowing simplicity of detection methods. In this study, an assay based on dimeric assembly of gold nanoparticles was developed for discriminating single nucleotide mismatches. Only gel electrophoresis is needed for assay readout. No other sophisticated or expensive equipment is required. In addition, no false-positive was observed in the readout. We used this assay for genotyping mutations in the Duchenne muscular dystrophy (DMD) gene, the largest known in the human genome. Our results show that conjugating the gold nanoparticles with short DNA probes of 18 bases and 70 bases complimentary to target sequences allows specific discrimination between wild-type and mutant sequences for c.4150G > T (NM.004006.1) mutation in exon 30 of the DMD gene using a simple colorimetric detection. This method allows identification of both the patients as well as the carriers of the mutation who are at risk of transmitting the disease.