Biomedical Engineering Reference
In-Depth Information
FIGURE 11.2
Reflected light microscopy images of micropatterns on the photomask. All the micropatterns are 10
μ
m
in width. The lighter areas are chromecoated and opaque and do not transmit light. The darker areas are
transparent and allows light to pass through. (A) Circles, (B) squares, (C) lines, and (D) diamonds.
11.5.2
Surface Functionalization of Silicon Substrates by Silanization
Silanization is the process of functionalizing the silicon or borosilicate substrates with a silane
solution resulting in the formation of a silane monolayer which acts as coupling agent between the
PEG hydrogel and silicon substrate, thereby improving the adherence of PEG hydrogel to the sili-
con substrate
[26]
. The silane solution used was 3-(trichlorosilyl) propyl methacrylate (TPM). It
was purchased from Sigma-Aldrich Chemical Co. (Germany). 1,1,1-Trichloroethane was purchased
from BDH Chemical Ltd (Poole, UK). Sulfuric acid and hydrogen peroxide were purchased from
Rockwood Electronic Materials (Derbyshire, UK). The silanization procedure was performed accord-
ing to the protocol described in published literatures
[26,27]
. The glass coverslips were heated in
“Piranha” solution, which is a mixture of aqueous solutions of 50% (v/v) sulfuric acid (3 parts) and
30% (w/v) hydrogen peroxide (1 part) for 10 min in a ventilated acid hood. The piranha solution was
handled with extreme care as it reacts violently with organic materials. Rubber gloves and personal
