Label-free and enzyme-free one-step rapid colorimetric detection of DNA methylation based on unmodified gold nanoparticles

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 238; p. 118375
• Main Authors: Li, Zhi-Mei, Pi, Ting, Yan, Xi-Luan, Tang, Xiao-Meng, Deng, Rui-Hong, Zheng, Xiang-Juan
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05.09.2020
• Subjects: Au nanoparticles; Bisulfite conversion; Colorimetric analysis; Colorimetry - economics; Colorimetry - methods; DNA - blood; DNA - chemistry; DNA Methylation; Gold - chemistry; Humans; Metal Nanoparticles - chemistry; Time Factors; UV absorption; DNA methylation; UV absorption; Au nanoparticles; Colorimetric analysis; Bisulfite conversion
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2020.118375

DNA methylation has been identified as one of the important causes of tumorigenesis, so it is important to develop some advanced methods for detecting and quantifying DNA methylation. In this study, a label-free and enzyme-free one-step rapid colorimetric detection of DNA methylation based on unmodified Au nanoparticles(Au NPs)has been proposed. This method can quickly, efficiently, economically and easily colorimetric detect methylated DNA only by the color change of unmodified Au NPs solution without the covalent modification of Au NPs in advance or complicated instruments for implementation with practical limitations or expensive biological enzymes or traditional organic dyes during the reaction. The strategy employed the difference in electrostatic attraction of single-stranded DNA and double-stranded DNA against salt-induced aggregation of Au NPs. The method has a DNA methylated detection limit of 8.47 nM and it is distinctly visible to detect methylated DNA with the naked eye as low as 20 nM. Furthermore, the strategy has an ability to detect methylated DNA in the presence of abundant unmethylated DNA with the detection limit of 0.13% and as low as 1% methylated DNA can be distinguished in heterogeneous samples with the naked eye. Also, the stratagem provides a convenient and rapid platform for methylated DNA detection of human serum samples in one step, which displays a huge potential for clinical diagnosis and treatment of oncological diseases. A label-free, ingenious and enzyme-free visual detection of DNA methylation based on unmodified gold nanoparticles has been constructed. [Display omitted] •DNA methylation has been visually detected by the aid of the difference in electrostatic attraction of single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) against salt-induced aggregation of unmodified gold nanoparticles (Au NPs).•The whole assay process can be carried out in homogeneous samples with the naked eye, without the requirement for covalent modification of Au NPs in advance, expensive biological enzymes, fluorescence-labelled or complicated instruments.•the sensitivity (8.47 nM) of DNA methylation could be analyzed, and this method also be applied for distinguishing of methylated cytosine DNA from abundant unmethylated DNA with the LOD of 0.13%.•This method offered the methodology for DNA methylation detection in complex biological samples, that is straightforward and versatile, and thus it might be promising to other biosensing fields.