Voltammetric Microwell Array for Oxidized Guanosine in Intact ds-DNA

详细信息    查看全文

• 作者：Boya Song ; Shenmin Pan ; Chi Tang ; Dandan Li ; James F. Rusling
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：November 19, 2013
• 年：2013
• 卷：85
• 期：22
• 页码：11061-11067
• 全文大小：389K
• 年卷期：v.85,no.22(November 19, 2013)
• ISSN：1520-6882

文摘

Oxidative stress in humans causes damage to biomolecules by generating reactive oxygen species (ROS). DNA can be oxidatively damaged by ROS, which may lead to carcinogenesis. Here we report a microfluidic electrochemical array designed to rapidly detect oxidation in intact DNA in replicate measurements. Sensor arrays were fabricated by wet-chemistry patterning of gold compact discs. The eight-sensor array is incorporated into a 60 渭L microfluidic channel connected to a pump and sample valve. The array features 7 nm thick osmium bipyridyl poly(vinylpyridine) chloride [Os(bpy)₂(PVP)₁₀Cl]⁺ films assembled layer-by-layer with polyions onto the gold sensors. 8-Hydroxy-7,8-hydro-2鈥?deoxyguanosine (8-oxodG) is selectively oxidized by [Os(bpy)₂(PVP)₁₀Cl]⁺ in intact ds-DNA to provide catalytic square wave voltammograms (SWV). The device is easy-to-use, fast, inexpensive, reusable, and can detect one 8-oxodG per 6600 nucleobases. The mass detection limit is 150-fold lower than a previously reported dip-and-read voltammetric sensor for oxidized DNA. Fast assays (<1 min) and moderate sample consumption (15 pmol DNA) suggest potential for research and clinical applications. Practical use is illustrated by detecting DNA oxidation from cigarette smoke and ash extracts in dispersions with NADPH and Cu²⁺.