The development of a highly accurate electrochemiluminescence
(ECL)
signal switch to avoid nonspecific stimulus responses is currently
a significant and challenging task. Here, we constructed a universal
signal switch utilizing a luminophore–quencher pair of mesostructured
silica xerogel-confined polymer and gold nanoparticles (Au NPs) that
can accurately detect low-abundance epigenetic markers in complex
sample systems. Notably, the ECL polymer encapsulated in mesostructured
silica xerogel acts as a luminophore, which demonstrated a highly
specific dependence on the Au NPs-mediated energy transfer quenching.
To demonstrate the feasibility, we specifically labeled the 5-hydroxymethylcytosine
(5hmC) site on the random sequence using a double-stranded (dsDNA)
tag that was skillfully designed with the CRISPR/Cas12a activator
and recombinant polymerase amplification (RPA) template. After amplification
by RPA, a large amount of dsDNA tag was generated as the activator
to initiate the trans-cleavage activity of CRISPR/Cas12a and subsequently
activate the signal switch, allowing for precise quantification of
5hmC. The ECL signal switch improves the stability of the luminophore
and prevents nonspecific stimulus responses, providing a new paradigm
for constructing high-precision biosensors.