Micropatterning of Substrates and Cells - Introduction to BioMEMS - page 82

immobilization step, thus exposing the protein pattern to strong solvents. One may also design
stencil masks that can be physically removed (e.g., peeled of). In fact, Carter's work (see Figure
2.23 ) constitutes an early example of stencil masks applied to micropatterning materials with
diferent cellular adhesiveness. A collaborative team led by Mehmet Toner (Harvard Medical
School) and David Beebe (then at University of Illinois at Urbana-Champaign) micromolded
approximately 50- to 100-μm-thick PDMS stencils (see Section 1.6.5) which could be applied non-
destructively onto a substrate to mask any aqueous surface chemistry. Because the stencil forms
a seal with the substrate, surface modiication occurs only on areas that are exposed through the
holes. Ater rinsing, the PDMS stencil may be peeled of, leaving a protein micropattern. Note

1 2

Fibroblasts

Stencil

4 3

Polystyrene

100 µm

FIGURE 2.35 Elastomeric.stencils.for.cell.patterning..(From.A..Folch,.B.-H..Jo,.O..Hurtado,.D. J..
Beebe,. and. M.. Toner,. “Microfabricated. elastomeric. stencils. for. micropatterning. cell. cultures,”.
J. Biomed. Mater. Res. 52,.346,.2000..Figure.contributed.by.the.author.)

Gold

6 mm

Glass

Glass cylinder

Single keratinocytes

Collagen gel

100 µm

Polystyrene

FIGURE 2.36 Cellular. microstructures. created. with. PDMS. stencils..(From. A.. Folch,. B.-H.. Jo,. O..
Hurtado,.D..J..Beebe,.and.M..Toner,.“Microfabricated.elastomeric.stencils.for.micropatterning.cell.
cultures,”. J. Biomed. Mater. Res. .52,.346,.2000..Figure.contributed.by.the.author.)