This invention discloses a
plasmon resonance detection method for hepatobiliary-specific
methylation sites. The method first immobilizes a sequence-specific
DNA capture probe on a gold
membrane surface and covalently couples it with a
methylation-
binding domain protein, constructing a sensor interface with dual functions of sequence capture and
methylation recognition. During detection, a pre-treated
plasma circulating
cell-
free DNA single-stranded sample is introduced into the sensor. The target
DNA first hybridizes with the capture probe, and then its
methylation site is specifically bound by the adjacent methylation-
binding domain protein, triggering two consecutive specific
surface plasmon resonance signal responses. By analyzing the increment between the two stable
signal values and comparing it with a preset threshold,
label-free, real-time, and highly specific determination of the methylation status of the
target site can be achieved. This invention eliminates the need for bisulfate treatment, effectively preserving
DNA integrity, and is particularly suitable for high-sensitivity detection of
hepatobiliary disease-related epigenetic markers in trace circulating
cell-
free DNA.