TY - JOUR
T1 - Flux characteristics of cell culture medium in rectangular microchannels
AU - Feng, Zhonggang
AU - Fukuda, Shuhei
AU - Yokoyama, Michio
AU - Kitajima, Tatsuo
AU - Nakamura, Takao
AU - Umezu, Mitsuo
PY - 2011/9
Y1 - 2011/9
N2 - Rectangular microchannels 50 μm high and 30, 40, 50, 60, or 70 μm wide were fabricated by adjusting the width of a gap cut in a polyethylene sheet 50 μm thick and sandwiching the sheet between an acrylic plate and a glass plate. Flux in the microchannels was measured under three different inner surface conditions: uncoated, albumin-coated, and confluent growth of rat fibroblasts on the bottom of the microchannels. The normalized flux in microchannels with cultured fibroblasts or albumin coating was significantly larger than that in the uncoated channels. The experimental data for all microchannels deviated from that predicted by classical hydrodynamic theory. At small aspect ratio the flux in the microchannels was larger than that predicted theoretically, whereas it became smaller at large aspect ratio. The aspect ratio rather than Reynolds number is the correct property for predicting the variation of the normalized friction factor. We postulate that two counteracting effects, rotation of large molecules and slip velocity at the corners of the microchannels, are responsible for the deviation. From these results we conclude that albumin coating should be carried out in the same way as when fabricating our integrating cell-culture system. The outcomes of this study are not only important for the design of our culture system, but also quite informative for general microfluidics.
AB - Rectangular microchannels 50 μm high and 30, 40, 50, 60, or 70 μm wide were fabricated by adjusting the width of a gap cut in a polyethylene sheet 50 μm thick and sandwiching the sheet between an acrylic plate and a glass plate. Flux in the microchannels was measured under three different inner surface conditions: uncoated, albumin-coated, and confluent growth of rat fibroblasts on the bottom of the microchannels. The normalized flux in microchannels with cultured fibroblasts or albumin coating was significantly larger than that in the uncoated channels. The experimental data for all microchannels deviated from that predicted by classical hydrodynamic theory. At small aspect ratio the flux in the microchannels was larger than that predicted theoretically, whereas it became smaller at large aspect ratio. The aspect ratio rather than Reynolds number is the correct property for predicting the variation of the normalized friction factor. We postulate that two counteracting effects, rotation of large molecules and slip velocity at the corners of the microchannels, are responsible for the deviation. From these results we conclude that albumin coating should be carried out in the same way as when fabricating our integrating cell-culture system. The outcomes of this study are not only important for the design of our culture system, but also quite informative for general microfluidics.
KW - Albumin coating
KW - Aspect ratio
KW - Cultured fibroblasts
KW - Flux
KW - Normalized friction factor
KW - Rectangular microchannels
KW - Reynolds number
UR - http://www.scopus.com/inward/record.url?scp=80052862790&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80052862790&partnerID=8YFLogxK
U2 - 10.1007/s10047-011-0564-x
DO - 10.1007/s10047-011-0564-x
M3 - Article
C2 - 21505818
AN - SCOPUS:80052862790
VL - 14
SP - 238
EP - 244
JO - Journal of Artificial Organs
JF - Journal of Artificial Organs
SN - 1434-7229
IS - 3
ER -