Gold nanostar based biosensor detects epigenetic alterations on promoter of real cells

Epigenetic changes, particularly in cancer suppressor genes, are novel biomarkers for cancer diagnostics and therapeutics. However, epigenetic studies should not only provide an estimation of the amount of 5-methylcytosine, but also examine the presence of epigenetic proteins to reveal the complete epigenetic alterations for downstream molecular process. The challenge of natural epigenetics is to unveil key factors of epigenetics in one assay, containing low concentrations. This would be valuable for the monitoring of early-stage cancer. On the basic of the nanoplasmonic biosensor, here we report a sensitive sensor to study epigenetics of DNA promoter. The results show detection limit for dual epigenetic biomarkers methyl-CpG group and methyl-CpG binding domain protein 2 (MBD2) are one 5-methylcytosine molecule and 125 fM MBD2. Moreover, DNA structure bending, steric competition under interaction of epigenetic proteins and transcription factors; and epigenetics-mediated suppression of transcription are observed during epigenetic alterations. This study provides a platform for full story of epigenetics, as compared with that of methylcytosine-based techniques only.