A reusable laser wrapped graphene-Ag array based SERS sensor for trace detection of genomic DNA methylation.
Methylation is an important epigenetic DNA modification that governs gene expression. The genomic level of methylated DNA and its derivatives may serve as important indicators for the initiation and progression of cancers among other diseases. In this effort we propose a new laser wrapped graphene-Ag array as a highly sensitive Surface-enhanced Raman spectroscopy (SERS) sensor for the detection of methylated DNA (5-methylcytosine, 5mC) and its oxidation derivatives namely 5-hydroxymethylcytosine (5-hmC) and 5-carboxylcytosine (5-caC). Excellent sensitivity and reproducibility were achieved with the laser wrapped graphene-Ag array as a substrate, with the graphene layer acting as an enhancer of the SERS signal due to the effective coupling of the electromagnetic field. In summary, fast (less than 60min) and sensitive (at a limit of detection 0.2pgμL-1, ie. 1.8pmolL-1) detection of methylated DNA and its derivatives was realized with the ability to distinguish methylation levels from a mixture at 0.1%. The sensitive and accurate detection in DNA extracted from cells was also accomplished. Furthermore our graphene wrapped approach circumvents the direct interaction between Ag array and the analytes, thus improving the reusability of the SERS substrate even after five cycles of use.
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China; Department of Agriculture & Biological Engineering, Bindley Bioscience Center, Purdue Center for Cancer Research, Purdue University, West Lafayette 47907, IN, USA.
Lei
L
Ouyang
School of Industrial Engineering, Purdue University, West Lafayette 47907, IN, USA.
Yaowu
Y
Hu
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: lhzhu63@hust.edu.cn.
Lihua
L
Zhu
School of Industrial Engineering, Purdue University, West Lafayette 47907, IN, USA.
Gary J
GJ
Cheng
Department of Agriculture & Biological Engineering, Bindley Bioscience Center, Purdue Center for Cancer Research, Purdue University, West Lafayette 47907, IN, USA. Electronic address: josephi@purdue.edu.
Joseph
J
Irudayaraj
D044503:5-Methylcytosine / Q000031:analogs & derivatives* / Q000032:analysis*; D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D045744:Cell Line, Tumor; D003596:Cytosine / Q000031:analogs & derivatives* / Q000032:analysis; D004247:DNA / Q000737:chemistry*; D019175:DNA Methylation; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D015203:Reproducibility of Results; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000295:instrumentation / Q000379:methods*
C560974:5-carboxylcytosine; D055910:Antibodies, Immobilized; C011865:5-hydroxymethylcytosine; D012834:Silver; D044503:5-Methylcytosine; D006046:Gold; D006108:Graphite; D003596:Cytosine; D004247:DNA
DNA methylation; Graphene-Ag array; Laser wrapping; SERS