Detection of Protein by Reduced Graphene Oxide Field-Effect Transistor
- PDF / 714,531 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 17 Downloads / 255 Views
Detection of Protein by Reduced Graphene Oxide Field-Effect Transistor Masaki Hasegawa1, Yuki Hirayama1, Yasuhide Ohno2, Kenzo Maehashi2, and Kazuhiko Matsumoto2 1 Merck Ltd., Japan, 4084 Nakatsu, Aikawa, Aiko, Kanagawa 243-0303, Japan 2 The Institute of the Science and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan ABSTRACT We confirmed a specific detection of immunoglobulin E(IgE) by using an aptamer immobilized reduced graphene oxide(rGo) field effect transistor(FET). A detection limit and dynamic range were estimated 8.1 ng/ml and 10000 respectively. These characteristics are comparable with current fluorescent markers. Although a mobility of rGo FET was around 5 cm2/V.sec, and this is two to three orders lower than mechanically exfoliated pristine graphene FET, a sensitivity of it was only one order lower than using pristine graphene. INTRODUCTION Recently, healthcare and food safety have strong attention because of aged society, environmental and food concerns. In these fields, biosensors to detect specific protein play important roles for diagnosis and detecting food and water contaminations. Currently, fluorescence marker detection technologies, such as Enzyme-Linked ImmunoSorbent Assay (ELISA), are used. However, these require complicated processes and take long time to get results. To overcome these problems, electric biosensors have been developing recently. The most common approach of electric biosensor is to configure a field effect transistor(FET) with semiconductor materials. Nowadays, many types of semiconductor are known, silicon, organic, metal oxide, and nano-carbon such as fullerene, carbon nano-tubes (CNT) and graphene. Graphene is well known material having a huge mobility, and is expected to show a high sensitivity for sensor applications. Recently, Y. Ohno et al. reported a detection of protein by using pristine graphene[1,2]. To consider a productivity of graphene biosensor, reduced graphene oxide (rGO) is suitable because of its low fabrication cost and easiness of device assembly especially for printing process. Therefore, we examined a feasibility of it for an application of biosensor. EXPERIMENT Fabrication of rGO-FET biosensor An rGO-FET biosensor was assembled as shown in Fig. 1. Graphene oxide (GO) was fabricated by using a modified Hummer method[2]. The sizes of GO flakes and layer number depend on days of stirring and condition of centrifugation. Drain and source electrodes were patterned on a silicon substrate. Before coating GO on the substrate, it was coated by aminopropyltrimethoxysilane (ATPS) to improve adhesion between a substrate and GO. The substrate was dipped into ATPS solution in water. An ATPS coated silicon substrate was coated with GO by using dip coating. A GO coated substrate was reduced by using ascorbic acid. Usually hydragine or high temperature annealing with hydrogen gas are used for reduction of GO. However, our objective to use an rGO is to develop a low cost biosensor, and we choose a practical reduction process which ca
Data Loading...
