epigenetic events such as dna methylation play important roles in the regulation of gene expression . dna methylation patterns have been found to differ between healthy and diseased tissue , such as healthy and cancerous tissue , thereby allowing dna methylation to serve as a biomarker for disease states . embodiments of the invention provide methods for detecting methylation patterns in dna polymers . methylation patterns are detected , in part , through the use of surface enhanced raman spectroscopy . sers provides a sensitive structure - based technique for chemical analysis .