Cell-Based Chips for Biotechnology - Introduction to BioMEMS - page 260

Fabricate microwell
patterned substrates

Align the primary array of
microchannels on microwells

PDMS
microfluidic mold

Flow each cell type in a specific
channel and wait for cells to dock
in the microwells

200 µm

Remove the microfluidic mold

Orthogonally align and attach the
second array of microchannels

200 µm

Run test conditions

FIGURE 5.18 Microwells. addressed. with. microluidics.. (From. Ali. Khademhosseini,. Judy. Yeh,.
George. Eng,. Jeffrey. Karp,. Hirokazu. Kaji,. Jeffrey. Borenstein,. Omid. C.. Farokhzad,. and. Robert.
Langer,.“Cell.docking.inside.microwells.within.reversibly.sealed.microluidic.channels.for.fabricat-
ing. multiphenotype. cell. arrays,”. Lab Chip . 5,. 1380-1386,. 2005.. Reproduced. with. permission.
from.The.Royal.Society.of.Chemistry.)

5.3.3 PEG Microwells
he microwells need not be made of PDMS. As a matter of fact, for applications in which the
cells are adherent and grow over time, it is best if they are made of a cell-repellent material. his
is exactly the reasoning behind making the microwells out of PEG ( Figure 5.19 ). he images in
Figure 5.19b and c show a culture of embryonic stem (ES) cells inside 100-μm-diameter PEG
wells that were seeded with ES cells and washed.

(a) PEG
microwells

Seeded cells Cells washed

and grown

(b) (c)

100 μm

5 kV

× 350 50 μm

FIGURE 5.19 Cell.trapping.with.PEG.microwells..(From.Ali.Khademhosseini,.Robert.Langer,.Jeffrey.
Borenstein,.and.Joseph.P..Vacanti,.“Microscale.technologies.for.tissue.engineering.and.biology,”.
Proc. Natl. Acad. Sci. U. S. A. .103,.2480-2487,.2006..Copyright.(2006).National.Academy.of.
Sciences,.U..S..A.)