Ni foam: a novel three-dimensional porous sensing platform for sensitive and selective nonenzymatic glucose detection Wenbo Lu, a Xiaoyun Qin, a Abdullah M. Asiri, bc Abdulrahman O. Al-Youbi bc and Xuping Sun * abc The present communication reports on the first use of commercially available three-dimensional porous Ni foam (NF) as a novel electro- chemical sensing platform for nonenzymatic glucose detection. NF not only acts as a working electrode, but also functions as an effective electrocatalyst for electrooxidation of glucose. The sensor exhibits high selectivity toward glucose. The linear range and limit of detec- tion were 0.05–7.35 mM (R ¼ 0.995) and 2.2 mM with a signal-to- noise ratio of 3, respectively. The application of this glucose sensor in human blood serum has also been demonstrated successfully. The detection of glucose has been attracting great attention due to its practical applications in biotechnology, clinical diagnostics, food industry, etc. 1 As a result, much attention has been paid to devel- oping sensitive, selective, and cost-effective approaches for glucose detection. 2 Compared to other detection methods, the electro- chemical technique is a promising tool for constructing simple and low-cost sensors due to its remarkable features such as high sensitivity, simple instrumentation, reliability, selectivity, and ease of operation. 3 Glucose oxidase (GOD) as a natural enzyme has high substrate specicity and high efficiency under mild conditions 4 and has thus been widely used as a biological catalyst for electro- chemical glucose determinations. 5 Unfortunately, natural enzymes are proteins and inherently bear some serious disadvantages, such as easy denaturation by environmental changes, digestion by proteases, time-consuming and expensive preparation and puri- cation. 6 Therefore, it is highly desired to develop nonenzymatic glucose sensors based on direct electrocatalytic oxidation of glucose at an electrode surface. Precious metals (Pt, Au, Pd) and their alloys (Pt–Pb, Pt–Ru, Pt–Au) were found to exhibit good catalytical activity toward electrooxidation of glucose and have been widely used for nonenzymatic glucose detection. 7 However, precious metal-based catalysts suffer from high cost, limiting their practical applications. Accordingly, much effort has been put into developing low-cost, non-noble metal-based electrocatalysts. Researchers have demon- strated that metals (Ni, Cu) and metal oxides (CuO, Co 3 O 4 , NiO) can also be used as effective electrocatalysts in this assay. 7 It is shown that Ni nanoparticles exhibit great enhancement in the electro- oxidation of glucose compared to other metallic nanoparticle-based electrodes. 8 Ni-based glucose electrochemical biosensors have been fabricated by electrodeposition of Ni within a nanopore poly- carbonate membrane template 8 or on a Ti/TiO 2 nanotube array, 9 or by deposition of Ni-containing nanohybrids on electrode surfaces. 7a However, all these methods suffer from complex and time- consuming synthesis routes or the involvement of hazardous reagents. As discussed by Long and Rolison, a three-dimensional (3D) interpenetrating network of electron and ion pathways should be an ideal electrode architecture to allow for efficient ion and electron transport. 10 It is therefore expected that a 3D Ni structure should also be an ideal electrode architecture for nonenzymatic glucose detection, but to the best of our knowledge, this point has not been addressed before. In this communication, we demonstrate the rst use of commercially available three-dimensional (3D) porous Ni foam (NF) as a working electrode and an effective electrocatalyst simulta- neously for electrooxidation of glucose. This nonenzymatic electro- chemical glucose sensor exhibits high selectivity toward glucose and the linear range and limit of detection (LOD) were 0.05–7.35 mM (R ¼ 0.995) and 2.2 mM with a signal-to-noise ratio of 3, respectively. We further demonstrate the successful application of this glucose sensor in human blood serum. Compared with previously reported Ni-based nonenzymatic glucose sensors, the NF sensor is a single- component system integrating the working electrode and the elec- trocatalyst and is thus very simple and time-saving. An additional advantage is that NF provides an interconnected electrolyte- lled pore network that guarantees high accessibleness and enables rapid ion transport. Glucose was purchased from Aladin Co., Ltd (Shanghai, China). Ascorbic acid (AA), dopamine (DA), uric acid (UA), L-Cysteine (L-Cys) a State Key Lab of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, P. R. China. E-mail: sunxp@ciac.jl.cn; Fax: +86 431-85262065; Tel: +86 431-85262065 b Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia c Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia Cite this: Analyst, 2013, 138, 417 Received 16th August 2012 Accepted 9th November 2012 DOI: 10.1039/c2an36138h www.rsc.org/analyst This journal is ª The Royal Society of Chemistry 2013 Analyst, 2013, 138, 417–420 | 417 Analyst COMMUNICATION Downloaded by Changchun Institute of Applied Chemistry, CAS on 05 January 2013 Published on 12 November 2012 on http://pubs.rsc.org | doi:10.1039/C2AN36138H View Article Online View Journal | View Issue