This work investigated the electrokinetic focusing and dispensing of polystyrene particles and red blood cells on microfluidic chips. Particles or cells were first electrokinetically focused using the merging of focusing streams on the sample stream, and subsequently separated as a result of the focusing. These particles or cells were then selectively dispensed from the focused sample stream using precise application of electrical pulses. The whole process of focusing, separation and dispensing of particles was visualized by a custom-made microscopy system. In particular, the width of the focused fluorescein stream and the accelerated electrophoretic motion of particles and cells were measured in a cross-channel and compared with a proposed analytical model. The electrokinetic manipulation of particles and cells demonstrated in this work can be used for developing integrated lab-on-a-chip devices for studies of cells.

1.
Reyes
D. R.
;
Iossifidis
D.
;
Aurous
P.
;
Manz
A.
Anal. Chem.
74
,
2623
36
(
2002
).
2.
Stone
H. A.
;
Stroock
A. D.
;
Ajdari
A.
Annu. Rev. Fluid. Mech.
36
,
381
411
(
2004
).
3.
Verpoorte
E.
Lab Chip
3
,
60N–68N
60N–68N
(
2003
).
4.
Jacobson
S. C.
;
Culberston
C. T.
;
Daler
J. E.
;
Ramsey
J. M.
Anal. Chem.
70
,
3476
80
(
1998
).
5.
Fu
Y.
;
Spence
C.
;
Scherer
A.
;
Arnold
F. H.
;
Quake
S. R.
Nature Biotech.
17
,
1109
11
(
1999
).
6.
Lee
G.
;
Lin
C.
;
Chang
G.
Sens. Actuat. A
2003
,
103
,
165
70
.
7.
Pabit
S. A.
;
Hagen
S. J.
Biophys. J.
83
,
2872
8
(
2002
).
8.
Wolff
A.
;
Perch-Nielsen
I. R.
;
Larsen
U. D.
;
Friis
P.
et al.
Lab Chip
3
,
22
7
(
2003
).
9.
Jacobson
S. C.
;
Ramsey
J. M.
Anal. Chem.
69
,
3212
7
(
1997
).
10.
Fu
L.
;
Yang
R.
;
Lee
G.
Anal. Chem.
75
,
1905
10
(
2003
).
11.
Dittrich
P. S.
;
Schwille
P.
Anal. Chem.
75
,
5767
74
(
2003
).
12.
Li, D. Electrokinetics in microfluidics, Elsevier Academic Press, Burlington, MA, 2004.
13.
Xuan, X.; Li, D. 2004 (submitted)
14.
Xuan
X.
;
Ye
C.
;
Li
D.
J. Colloid. Interf. Sci.
289
,
286
90
(
2005
).
15.
Xuan, X.; Xu, B.; Li, D. Anal. Chem. 2005 (in press).
16.
Li
P. C. H.
;
Harrison
D. J.
Anal. Chem.
69
,
1564
8
(
1997
).
17.
Blankenstein
G.
;
Larsen
U. D.
Biosens. Bioelectron.
13
,
427
38
(
1998
).
18.
Fu
A. Y.
;
Chou
H.
;
Spence
C.
;
Arnold
F. H.
;
Quake
S. R.
Anal. Chem.
74
,
2451
7
(
2002
).
19.
Johann
R.
;
Renaud
.
Electrophoresis
25
,
3720
9
(
2004
).
20.
Fideler
S.
;
Shirley
S. G.
;
Schnelie
T.
;
Fuhr
G.
Anal. Chem.
70
,
1909
15
(
1998
).
21.
Wang
M. M.
;
Tu
E.
;
Raymond
D. E.
;
Yang
J. M.
et al.
Nature Biotech.
23
,
83
7
(
2005
).
22.
Duffy
D. C.
;
McDonald
J. C.
;
Schueller
O. J. A.
;
Whitesides
G. M.
Anal. Chem.
70
,
4974
84
(
1998
).
23.
Xuan
X.
;
Li
D. C.
;
J. Micromech. Microeng.
14
,
290
298
(
2004
).
24.
Santiago
J. G.
Anal. Chem.
73
,
2353
65
(
2001
).
25.
Ye
C.
;
Xuan
X.
;
Li
D.
Microfluid. Nanofluid.
1
,
234
41
(
2005
).
26.
Pohl, H. A. Dielectrophoresis. Cambridge University Press, Cambridge, 1978.
27.
Rush
R. S.
;
Cohen
A. S.
;
Karger
B. L.
,
Anal. Chem.
63
,
1346
50
(
1991
).
This content is only available via PDF.
You do not currently have access to this content.