A puncher was used to create inlet and outlet holes in the PDMS piece for the later insertion of needles and the connection of tubing. After an O2 plasma treatment to both the Au-on-glass electrodes and the PDMS microfluidic channels, the two pieces were carefully aligned and pressed to contact. After baking at 80 o C for 5 min permanent bonds formed between them. Needles and tubing were then attached to guide the flow in and out of the microfluidic channel.