Enzymatic Control of Plasmonic Coupling and Surface Enhanced Raman Scattering Transduction for Sensitive Detection of DNA Demethylation

We have developed a novel concept for enzymatic control of plasmonic coupling as a surface enhanced Raman scattering (SERS) nanosensor for DNA demethylation. This nanosensor is constructed by decorating gold nanoparticles (AuNPs) with Raman reporters and hemimethylated DNA probes. Demethylation of DNA probes initiates a degradation reaction of the probes by methylation-sensitive endonuclease Bsh 12361 and single-strand selective exonuclease I. This destabilizes AuNPs and mediates the aggregation of AuNPs, generating a strong plasmonic coupling SEAS signal in response to DNA demethylation. This nanosensor has the advantages in its high signal-to-noise ratio, superb specificity, and rapid, convenient, and reproducible detection with homogeneous, single-step operation. Thus, it provides a useful platform for detecting DNA demethylation and related molecular diagnostics and drug screening. This work is the first time that enzymatic degradation of DNA substrate probes has been utilized to induce aggregation of AuNPs such that reproducible, sensitive SERS signals can be achieved from biological recognition events. This enzymatic control mechanism for plasmonic coupling may create a new paradigm for the development of SERS nanosensors.