Biomedical Microdevices 7:4, 281–293, 2005 C 2005 Springer Science + Business Media, Inc. Manufactured in The Netherlands. Characterization of Polydimethylsiloxane (PDMS) Properties for Biomedical Micro/Nanosystems Alvaro Mata,1,2 Aaron J. Fleischman,2 and Shuvo Roy2,∗ 1Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH 44115 2BioMEMS Laboratory, Department of Biomedical Engineering, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44120 E-mail:
[email protected] Abstract. Polydimethylsiloxane (PDMS SylgardR 184, Dow Corn- search and development of MEMS-based devices in the ing Corporation) pre-polymer was combined with increasing biomedical arena for a variety of applications ranging amounts of cross-linker (5.7, 10.0, 14.3, 21.4, and 42.9 wt.%) and from diagnostics (Fujii, 2002; Mastrangelo et al., 1998; designated PDMS1, PDMS2, PDMS3, PDMS4, and PDMS5,respec- tively. These materials were processed by spin coating and subjected Paranjape et al., 2003; Wu et al., 2001) to therapeutics to common microfabrication, micromachining, and biomedical pro- (Borenstein et al., 2002; Chung et al., 2003; Ferrara et al., cesses: chemical immersion, oxygen plasma treatment, sterilization, 2003; Santini et al., 1999; Tao and Desai, 2003). However, and exposure to tissue culture media. The PDMS formulations were the development of these applications through established analyzed by gravimetry, goniometry, tensile testing, nanoindenta- MEMS manufacturing approaches is hindered by inherent tion, scanning electron microscopy (SEM), Fourier transform in- frared spectroscopy (FTIR), and X-ray photoelectron spectroscopy characteristics of traditional silicon-based processes such (XPS). Spin coating of PDMS was formulation dependent with film as high costs and limited access to clean room environ- thickness ranging from 308 µmonPDMS1 to 171 µmonPDMS5 ments (Roy et al., 2001; Whitesides et al., 2001).