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. Author manuscript; available in PMC: 2010 Jan 31.
Published in final edited form as: Bioessays. 2008 Sep;30(9):811. doi: 10.1002/bies.20804

Figure 4.

Figure 4

Microfluidic channels fabricated from poly(dimethyl siloxane), (PDMS) have been shown to absorb small hydrophobic molecules. a: Quinine (fluoresceces at pH2, but not at pH7) was put into a channel and then washed out with pH2 water and fluorescence images of the channel taken. b: If quinine is incubated for 5 minutes in pH7 water in the channel no fluorescence is seen, but after the channel is washed with pH2 water, quinine begins to leach back into solution from the PDMS channel walls and remains until it is washed again. c: A similar phenomenon was shown for Nile Red, as even after the channel is washed with detergent and water, significant fluorescence indicates that the Nile Red was absorbed into the walls of the channels. Adapted from Toepke MW, Beebe DJ. 2006. PDMS absorption of small molecules and consequences in microfluidic applications. Lab On A Chip 6:1484–1486. Reproduced by permission of The Royal Society of Chemistry http://dx.doi.org/10.1039/b612140c.