Tamkang University 1 article published in JoVE Engineering One-Step Approach to Fabricating Polydimethylsiloxane Microfluidic Channels of Different Geometric Sections by Sequential Wet Etching Processes Chien-Kai Wang1,2, Wei-Hao Liao1, Hsiao-Mei Wu1, Yi-Chung Tung1,3 1Research Center for Applied Sciences, Academia Sinica, 2Department of Civil Engineering, Tamkang University, 3College of Engineering, Chang Gung University Several methods are available for the fabrication of channels of non-rectangular sections embedded in polydimethylsiloxane microfluidic devices. Most of them involve multistep manufacturing and extensive alignment. In this paper, a one-step approach is reported for fabricating microfluidic channels of different geometric cross sections by polydimethylsiloxane sequential wet etching.