Surface Plasmon Resonance Imaging-Based Platform Enables Detection of Single, Site-Specific 5-Methylcytosine Associated with Post-traumatic Stress Disorder (PTSD).

While identification of epigenetic changes in individuals with psychiatric dysfunctions such as post-traumatic stress disorder (PTSD) is paramount to genomic research, there is no rapid and simplified way to detect an epigenetic marker such as DNA methylation in genes. Here, we introduce a faster, simpler method to detect methylation in the form of 5-methylcytosine (5mC, termed as PTSD-associated base) in known CpG sites using nanoenhanced surface plasmon resonance imaging-based epigenetic assay (EpiNanoSPRi). This assay platform simultaneously detects a panel of single, site-specific PTSD bases in target genes or regions using an anti-5mC antibody and a universal nanoenhancer on a gold-coated sensing chip. Not only can EpiNanoSPRi identify 5mC at the single-base level, but it also can quantify the extent of DNA methylation. Our method is superior and more practical to bisulfite-based DNA sequencing techniques as it will significantly reduce DNA methylation identification from 4 days (e.g., DNA Sequencing) to 9 h without massive analysis workflow. This platform can potentially be applied to diagnose other psychiatric disorders such as Alzheimer's, Parkinson's, dementia, schizophrenia, and Huntington's diseases.