Compositions and methods of cell attachment
Compositions, devices and methods are described for improving adhesion, attachment, and/or differentiation of cells in a microfluidic device or chip. In one embodiment, one or more ECM proteins are covalently coupled to the surface of a microchannel of a microfluidic device. The microfluidic devices can be stored or used immediately for culture and/or support of living cells such as mammalian cells, and/or for simulating a function of a tissue, e.g., a liver tissue, muscle tissue, etc. Extended adhesion and viability with sustained function over time is observed.
1. A method of culturing cells, comprising:
a) providing a microfluidic device comprising a microchannel comprising a polydimethylsiloxane surface, said polydimethylsiloxane surface reacted with an ultraviolet light reactive portion of a N-sulfosuccinimidyl-6-(4′-azido-2′-nitrophenylamino) hexanoate heterobifunctional crosslinker using an ultraviolet light source, said microchannel in fluidic communication with a fluid source comprising a fluid;
b) covalently attaching one or more extracellular matrix proteins to a chemically-reactive portion of said heterobifunctional crosslinker so as to create a treated surface;
c) seeding viable epithelial cells on said treated surface so as to create attached epithelial cells;
d) flowing said fluid from said fluid source through said microchannel so as to create flowing conditions; and
e) culturing said attached epithelial cells under said flow conditions such that said attached epithelial cells remain attached and viable for at least 7 days.
2. The method of claim 1 , wherein said one or more extracellular matrix proteins comprises collagen.
3. The method of claim 1 , wherein said one or ore extracellular proteins comprises RGD or a RGD motif.
4. A method of culturing cells, comprising:
a) providing a microfluidic device comprising a microchannel comprising a polydimethylsiloxane surface, said surface reacted with an ultraviolet light reactive portion of a N-sulfosuccinimidyl-6-(4′-azido-2′-nitrophenylamino) hexanoate crosslinker using a source of ultraviolet light, said microchannel in fluidic communication with a fluid source comprising a fluid;
b) covalently attaching one or more extracellular matrix proteins to a chemically-reactive portion of said crosslinker so as to create a treated surface;
c) seeding viable hepatocytes on said treated surface so as to create attached cells;
d) flowing said fluid from said fluid source through said microchannel so as to create flowing conditions; and
e) culturing said attached cells under said flow conditions such that said cells remain attached and viable for at least 7 days.
5. The method of claim 4 , wherein said hepatocytes are dog hepatocytes.
6. The method of claim 4 , further comprising f) assessing viability of said hepatocytes by measuring the level of activity of one or more cellular enzymes.
7. The method of claim 6 , wherein said cellular enzyme is a cytochrome P450 (CYP) enzyme.
8. The method of claim 4 , wherein said one or more extracellular matrix proteins comprise collagen.
9. The method of claim 4 , wherein said one or more extracellular proteins comprises RGD or a RGD motif.
10. The method of claim 4 , wherein said polydimethylsiloxane surface is plasma treated prior to step b).