<s>
Microcontact	B-Algorithm
printing	I-Algorithm
(	O
or	O
μCP	O
)	O
is	O
a	O
form	O
of	O
soft	B-Algorithm
lithography	I-Algorithm
that	O
uses	O
the	O
relief	O
patterns	O
on	O
a	O
master	O
polydimethylsiloxane	O
(	O
PDMS	O
)	O
stamp	O
or	O
Urethane	O
rubber	O
micro	O
stamp	O
to	O
form	O
patterns	O
of	O
self-assembled	O
monolayers	O
(	O
SAMs	O
)	O
of	O
ink	O
on	O
the	O
surface	O
of	O
a	O
substrate	O
through	O
conformal	O
contact	O
as	O
in	O
the	O
case	O
of	O
nanotransfer	O
printing	O
(	O
nTP	O
)	O
.	O
</s>
<s>
However	O
,	O
the	O
combination	O
of	O
the	O
two	O
gave	O
rise	O
to	O
the	O
method	O
of	O
microcontact	B-Algorithm
printing	I-Algorithm
.	O
</s>
<s>
Since	O
its	O
inception	O
many	O
methods	O
of	O
soft	B-Algorithm
lithography	I-Algorithm
have	O
been	O
explored	O
.	O
</s>
<s>
Creation	O
of	O
the	O
master	O
,	O
or	O
template	O
,	O
is	O
done	O
using	O
traditional	O
photolithography	B-Algorithm
techniques	O
.	O
</s>
<s>
Photoresist	O
is	O
applied	O
to	O
the	O
surface	O
and	O
patterned	O
by	O
a	O
photomask	B-Algorithm
and	O
UV	O
light	O
.	O
</s>
<s>
The	O
PDMS	B-Algorithm
stamp	I-Algorithm
,	O
in	O
most	O
applications	O
,	O
is	O
a	O
10:1	O
ratio	O
of	O
silicone	O
elastomer	O
and	O
a	O
silicone	O
elastomer	O
curing	O
agent	O
.	O
</s>
<s>
This	O
mixture	O
consists	O
of	O
a	O
short	O
hydrosilane	O
crosslinker	O
that	O
contains	O
a	O
catalyst	B-Device
made	O
from	O
a	O
platinum	B-Operating_System
complex	O
.	O
</s>
<s>
After	O
pouring	O
,	O
the	O
PDMS	O
is	O
cured	O
at	O
elevated	O
temperatures	O
to	O
create	O
a	O
solid	O
polymer	B-Language
with	O
elastomeric	O
properties	O
.	O
</s>
<s>
Some	O
commercial	O
services	O
for	O
procuring	O
PDMS	B-Algorithm
stamps	I-Algorithm
and	O
micropatterned	O
samples	O
exist	O
such	O
as	O
Research	O
Micro	O
Stamps	O
.	O
</s>
<s>
Microcontact	B-Algorithm
Printing	I-Algorithm
has	O
several	O
advantages	O
including	O
:	O
</s>
<s>
Can	O
be	O
done	O
in	O
a	O
traditional	O
laboratory	O
without	O
the	O
constant	O
use	O
of	O
a	O
cleanroom	B-Application
(	O
cleanroom	B-Application
is	O
needed	O
only	O
to	O
create	O
the	O
master	O
)	O
.	O
</s>
<s>
When	O
the	O
aspect	B-Device
ratio	I-Device
of	O
the	O
stamp	O
is	O
high	O
buckling	O
of	O
the	O
stamp	O
can	O
occur	O
.	O
</s>
<s>
When	O
the	O
aspect	B-Device
ratio	I-Device
is	O
low	O
roof	O
collapse	O
can	O
occur	O
.	O
</s>
<s>
Most	O
organic	O
solvents	O
induce	O
swelling	O
of	O
the	O
PDMS	B-Algorithm
stamp	I-Algorithm
.	O
</s>
<s>
Microcontact	B-Algorithm
printing	I-Algorithm
has	O
great	O
applications	O
in	O
micromachining	O
.	O
</s>
<s>
Once	O
the	O
ink	O
has	O
been	O
applied	O
to	O
the	O
substrate	O
the	O
SAM	O
layer	O
acts	O
as	O
a	O
resist	O
to	O
common	O
wet	B-Algorithm
etching	I-Algorithm
techniques	O
allowing	O
for	O
the	O
creation	O
of	O
high	O
resolution	O
patterning	O
.	O
</s>
<s>
For	O
example	O
,	O
applying	O
the	O
SAM	O
layer	O
on	O
top	O
of	O
gold	O
and	O
etching	B-Algorithm
creates	O
microstructures	O
of	O
gold	O
.	O
</s>
<s>
Because	O
of	O
the	O
microcontact	B-Algorithm
printing	I-Algorithm
technique	O
no	O
traditional	O
photolithography	B-Algorithm
is	O
needed	O
to	O
accomplish	O
these	O
steps	O
.	O
</s>
<s>
Various	O
proteins	O
have	O
been	O
proven	O
to	O
be	O
suitable	O
inks	O
and	O
are	O
applied	O
to	O
various	O
substrates	O
using	O
the	O
microcontact	B-Algorithm
printing	I-Algorithm
technique	O
.	O
</s>
<s>
Microcontact	B-Algorithm
printing	I-Algorithm
has	O
been	O
used	O
to	O
advance	O
the	O
understanding	O
of	O
how	O
cells	O
interact	O
with	O
substrates	O
.	O
</s>
<s>
The	O
stamps	O
were	O
able	O
to	O
be	O
used	O
multiple	O
times	O
that	O
were	O
more	O
homogeneous	B-General_Concept
and	O
sensitive	O
than	O
other	O
techniques	O
.	O
</s>
<s>
The	O
process	O
of	O
contact	O
was	O
automated	O
to	O
achieve	O
these	O
speeds	O
through	O
a	O
piezoelectric	O
actuator	B-Algorithm
.	O
</s>
<s>
Lift-off	O
Nanocontact	O
printing	O
:	O
By	O
first	O
using	O
Silicon	O
lift-off	O
stamps	O
and	O
later	O
low	O
cost	O
polymer	B-Language
lift-off	O
stamps	O
and	O
contacting	O
these	O
with	O
an	O
inked	O
flat	O
PDMS	B-Algorithm
stamp	I-Algorithm
,	O
nanopatterns	O
of	O
multiple	O
proteins	O
or	O
of	O
complex	O
digital	O
nanodot	O
gradients	O
with	O
dot	O
spacing	O
ranging	O
from	O
0nm	O
to	O
15um	O
apart	O
were	O
achieved	O
for	O
immunoassays	O
and	O
cell	O
assays	O
.	O
</s>
<s>
A	O
composite	O
,	O
thin	O
PDMS	B-Algorithm
stamp	I-Algorithm
with	O
a	O
rigid	O
back	O
support	O
has	O
been	O
used	O
for	O
patterning	O
to	O
help	O
solve	O
this	O
problem	O
.	O
</s>
<s>
Magnetic	O
field	O
assisted	O
micro	B-Algorithm
contact	I-Algorithm
printing	I-Algorithm
:	O
to	O
apply	O
a	O
homogeneous	B-General_Concept
pressure	O
during	O
the	O
printing	O
step	O
,	O
a	O
magnetic	O
force	O
is	O
used	O
.	O
</s>
<s>
Multiplexing	O
:	O
the	O
macrostamp	O
:	O
the	O
main	O
drawback	O
of	O
microcontact	B-Algorithm
printing	I-Algorithm
for	O
biomedical	O
application	O
is	O
that	O
it	O
is	O
not	O
possible	O
to	O
print	O
different	O
molecules	O
with	O
one	O
stamp	O
.	O
</s>
