Page 31 - Optofluidics Fundamentals, Devices, and Applications

12 Cha pte r T w o

PDMS

Initial (t = 0) (t = 1 h) (t = 4 h)
(a) (b) (c)

PDMS-SiO 2

(d) (e) (f)
250 250
t = 0 h t = 0 h
t = 1 h 200 t = 1 h
Fluorescence (arb. units) 150 Fluorescence (arb. units) 150
t = 4 h
t = 4 h
200

100
100
50
0 50 0
0 50 100 150 200 250 0 50 100 150 200 250
Distance (μm) Distance (μm)
(g) (h)

FIGURE 2-1 Images of PDMS (a-c) and PDMS-SiO (d-f) devices are shown. The channels
2
on these devices are fi lled with 10-μM rhodamine B in a 10-mM (pH 9.5) sodium borate
solution. The images were acquired over a 4-h period. Fluorescent profi les of the PDMS
and PDMS-SiO channels are also shown in (g) and (h), respectively. These profi les were
2
taken along the white dotted line in images (a-f). (Adapted with permission from G. T.
Roman, T. Hlaus, K. J. Bass, T. G. Seelhammer, and C. T. Culbertson, “Sol-gel
modifi ed poly(dimethylsiloxane) microfl uidic devices with high electroosmotic
mobilities and hydrophilic channel wall characteristics,” Anal. Chem., 77, (2005),
1414–1422.Copyright 2005 American Chemical Society.)

Toxicity
PDMS is nontoxic to proteins and cells. It is permeable to oxygen and
carbon dioxide, but only slowly permeable to water. It is therefore
suitable for biological studies: for example, mammalian cells can be
cultured on it directly [30].