GRAPHENE NANOSIEVE USING BLOCK COPOLYMER LITHOGRAPHY AND ITS APPLICATION TO SEPARATION OF HEMOGLOBIN PROTEIN AND IMMUNOGLOBLIN G Dae-Sik Lee* 1 , Suk Han Park 2 , Yong-Duk Han 3 , Jeong Won Park 1 , Mun Yeon Jung 1 , Sang Ouk Kim 2 , Hyun C. Yoon 3 , and Sung Yul Choi 4 1 BioMED Team, Electronics and Telecommunications Research Institute (ETRI), Korea, 2 Dept. of Materials Science and Engineering, KAIST, Korea, Japan, 3 Applied Biological Engineering, Ajou University, Korea, , 4 Dept. of Electrical Engineering, KAIST, Korea ABSTRACT This paper reports a graphene nanosieve using a unique block copolymer lithography method and its application to separation of hemoglobin (Hb) and human immunoglobulin G (IgG) proteins. The preliminary fabrication process for the nanopores using universal block copolymer lithography was reported in Advanced Materials. [1] Our method differs from that of group C. Dekker [2] in the specific method of grapheme nanopores fabrication and its targeting application of the DNA translocation. KEYWORDS Proteins separations, Nano sieve, Graphene, Block copolymer lithography INTRODUCTION Ultrathin nanosieves with nanopores are highly being important for their versatility and outstanding performance comparing to a commercialized nanoporous membrane.[3] Even though numerous methods have been reported, they are still very expensive and cannot be realized in a large scale,[4] or need a complicated processing technique. Here, we propose a unique and handy method for fabricating a nanosieve. Without any specialized photolithography, processes or equipment, general block copolymer spin coating and reactive ion etching (RIE) were only used. Spin coating and RIE are well-known and very reliably mass-producible processes. Thus, the proposed method has great advantages of low cost, reproducibility and high throughput. In this work 3~4 nm-thick graphene nanosieve was successfully manufactured, and the pores size could be controlled from several nanometer to several tens of nanometer, by controlling the mixing ratio of polymers and annealing temperatures. EXPERIMENT Figure 1 shows schematic diagram of the grapheme nanosieve fabrication using lithography process based on polystyrene (PS) - polymethyl metacrylate (PMMA) block copolymer. A nano-template of surface perpendicular PMMA cylinders in a PS matrix assembled on a graphene film (average diameter of PMMA cylinders: 15 nm, center-to-center distance between neighboring cylinders: 45 nm) was utilized and etched using RIE as shown in Fig. 1(b). (a) (b) Figure 1. Schematic diagram of the grapheme nanosieve using block copolymer lithography process (a), and the SEM photograph of grapheme sieve with nanopores of a diameter of 15 nm (b) . The etching grapheme nanofilm is transferred successfully to the 1.5 cm x 1.5 cm silicon device, which has low stresses SiN membrane with one micrometer-wide micropores (Figure 2). In order to investigate the separation ability of the grapheme nanopores, we did a separation test between the haemoglobin with a diameter of around 7 nm and the IgG with a diameter of above 15 nm. 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences October 28 - November 1, 2012, Okinawa, Japan 978-0-9798064-5-2/μTAS 2012/$20©12CBMS-0001 1816