Scanning Electrochemical Microscopy of DNA Hybridization on DNA Microarrays Enhanced by HRP-Modified SiO2 Nanoparticles

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• 作者：Huajun Fan ; Xiaolan Wang ; Fang Jiao ; Fan Zhang ; Qingjiang Wang ; Pingang He ; Yuzhi Fang
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：July 2, 2013
• 年：2013
• 卷：85
• 期：13
• 页码：6511-6517
• 全文大小：393K
• 年卷期：v.85,no.13(July 2, 2013)
• ISSN：1520-6882

文摘

Imaging of localized hybridization of nucleic acids immobilized on a glass DNA microarray was performed by means of generation collection (GC) mode scanning electrochemical microscopy (SECM). Amine-tethered oligodeoxynucleotide probes, spotted on the glass surface, were hybridized with an unmodified target sequence and a biotinylated indicator probe via sandwich hybridization. Spots where sequence-specific hybridization had occurred were modified by streptavidin-horseradish-peroxidase-(HRP)-wrapped SiO₂ nanoparticles through the biotin鈥搒treptavidin interaction. In the presence of H₂O₂, hydroquinone (H₂Q) was oxidized to benzoquinone (BQ) at the modified spot surface through the HRP catalytic reaction, and the generated BQ corresponding to the amount of target DNA was reduced in solution by an SECM tip. With this DNA microarray, a number of genes could be detected simultaneously and selectively enough to discriminate between complementary sequences and those containing base mismatches. The DNA targets at prepared spots could be imaged in SECM GC mode over a wide concentration range (10^鈥?鈥?0^鈥?2 M). This technique may find applications in genomic sequencing.