MICROPATTERNED POLYMER STRUCTURES FOR CELL AND TISSUE ENGINEERING - Biologically-Responsive Hybrid Biomaterials - page 91

1-100 Ⱥ m (Fig. 1A) [18]. Briefly, a PDMS stamp, fabricated in desired pattern
(Fig. 1A), is inked with a patterning solution and contacted onto a substrate after
solvent evaporation, resulting in a printed pattern. The hydrophobic nature of
PDMS can be changed to hydrophilic by exposing it to an oxygen plasma [23].
Some parameters such as humidity, pressure, time, and hydration should be
considered to control the surface chemistry and to inhibit the aggregation and
denaturation of proteins. Ⱥ CP eliminates the use of cytotoxic photoresists,
sophisticated clean-room facilities and achieves a good balance between
simplicity, low cost, reproducibility due to high fidelity, compatibility and high
filling efficiency of the treated surface [18, 24, 25].

B

A C

D E

Fig. 1. Microcontact printing for selective adhesion of cells to patterned substrate. (A) A schematic
diagram illustrating the generation of a lithographically defined master and a PDMS stamp with
replica molding: prepolymer PDMS is cast onto the master, cured and peeled to create a stamp with
relief features. Reprinted from [32]. (B) Immunofluorescent staining for phosphotyrosine (PY),
microtubules (tubulin) and phalloidin-Alexa488 staining for actin in B16F1 cells on a triangular
microetched island. Reprinted from [31]. (C) Cardiac cell sheet was stained for actin (green) and
fibronectin (red), and scratched using a thin needle to expose underlying fibronectin lines.
Reprinted from [37]. (D) Differential interference contrast images of endothelial cell pairs confined
to bow-tie-shaped patterns. Reprinted from [29]. (E) Human mesenchymal stem cells on small and
large fibronectin islands after 1 week of culture. The images indicate that cells on the small islands
stained for lipids, thus differentiating into adipogenic fate, whereas cells on large islands stained
for alkaline phosphatase and differentiated into osteoblasts. Reprinted from [38]. Scale bars: 10 µm
in (B), 200 µm in (C), 25 µm in (D), and 50 µm in (E).

Ⱥ CP has been employed to investigate complex cellular processes such as
adhesion, migration, growth, cell-cell interactions and gene expressions by