Preparation of a Superhydrophobic and Peroxidase-like Activity Array Chip for H2O2 Sensing by Surface-Enhanced Raman Scattering

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• 作者：Zhi Yu ; Yeonju Park ; Lei Chen ; Bing Zhao ; Young Mee Jung ; Qian Cong
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：October 28, 2015
• 年：2015
• 卷：7
• 期：42
• 页码：23472-23480
• 全文大小：499K
• ISSN：1944-8252

文摘

In this paper, we propose a novel and simple method for preparing a dual-biomimetic functional array possessing both superhydrophobic and peroxidase-like activity that can be used for hydrogen peroxide (H₂O₂) sensing. The proposed method is an integration innovation that combines the above two properties and surface-enhanced Raman scattering (SERS). We integrated a series of well-ordered arrays of Au points (d = 1 mm) onto a superhydrophobic copper (Cu)/silver (Ag) surface by replicating an arrayed molybdenum template. Instead of using photoresists and the traditional lithography method, we utilized a chemical etching method (a substitution reaction between Cu and HAuCl₄) with a Cu/Ag superhydrophobic surface as the barrier layer, which has the benefit of water repellency. The as-prepared Au points were observed to possess peroxidase-like activity, allowing for catalytic oxidation of the chromogenic molecule o-phenylenediamine dihydrochloride (OPD). Oxidation was evidenced by a color change in the presence of H₂O₂, which allows the array chip to act as an H₂O₂ sensor. In this study, the water repellency of the superhydrophobic surface was used to fabricate the array chip and increase the local reactant concentration during the catalytic reaction. As a result, the catalytic reaction occurred when only 2 渭L of an aqueous sample (OPD/H₂O₂) was placed onto the Au point, and the enzymatic product, 2,3-diaminophenazine, showed a SERS signal distinguishable from that of OPD after mixing with 2 渭L of colloidal Au. Using the dual-biomimetic functional array chip, quantitative analysis of H₂O₂ was performed by observing the change in the SERS spectra, which showed a concentration-dependent behavior for H₂O₂. This method allows for the detection of H₂O₂ at concentrations as low as 3 pmol per 2 渭L of sample, which is a considerable advantage in H₂O₂ analysis. The as-prepared substrate was convenient for H₂O₂ detection because only a small amount of sample was required in each analysis. Highly sensitive detection was realized using SERS. Therefore, this chip was shown to exhibit significant potential for applications in bioanalysis.