AI Article Synopsis

  • The study introduces a method for detecting DNA methylation using silver nanoclusters (AgNCs), which shows increased fluorescence for methylated DNA sequences associated with colorectal cancer.
  • It focuses on the Sept9 promoter region, where a specially designed probe DNA enhances AgNC formation when hybridized with methylated target sequences, leading to measurable fluorescence changes.
  • Results highlight that the fluorescence intensity is significantly higher for methylated targets compared to non-methylated ones, and the method is highly specific to target sequences, revealing a sequence-dependent behavior of the DNA with silver ions.

Article Abstract

Determining methylation state of a particular DNA sequence is an essential task in many epigenetic investigations. Here a facile method based on silver nanocluster (AgNCs) fluorescence enhancement is presented. Target sequences were selected from Sept9 promoter region that its hypermethylation is demonstrated as a reliable biomarker of colorectal cancer. Probe DNA was complementary to a 25 nucleotide of the target region and possessed twelve additional cytosines in the middle to grant the formation of AgNCs. After probe strands were hybridized with methylated and non-methylated targets separately, AgNCs were synthesized, and their fluorescence intensities were recorded. Fluorescence intensity enhanced when the target strands were methylated and quenched when they were non-methylated. The Linear range of fluorescence enhancement was from 1.0 × 107 M to 5.0 × 107 M with the detection limit of 7.6 × 108 M. Sensor specificity was checked with non-complementary strands with the maximum similarity of 40%. Further experiments explored various characteristics of methylated and non-methylated DNAs carrying AgNC and indicated that structure of methylated and non-methylated DNAs was affected differently by silver ions that could then influence AgNC fluorescence. This effect was strongly sequence-dependent, and either fluorescence enhancement or quenching was observed with two different sequences.

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Source
http://dx.doi.org/10.1016/j.aca.2018.07.025DOI Listing

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