<s>
A	O
nanomotor	B-Algorithm
is	O
a	O
molecular	O
or	O
nanoscale	O
device	O
capable	O
of	O
converting	O
energy	O
into	O
movement	O
.	O
</s>
<s>
The	O
purpose	O
of	O
the	O
bet	O
(	O
as	O
with	O
most	O
scientific	O
bets	O
)	O
was	O
to	O
inspire	O
scientists	O
to	O
develop	O
new	O
technologies	O
,	O
and	O
anyone	O
who	O
could	O
develop	O
a	O
nanomotor	B-Algorithm
could	O
claim	O
the	O
$	O
1,000	O
USD	O
prize	O
.	O
</s>
<s>
However	O
,	O
his	O
purpose	O
was	O
thwarted	O
by	O
William	O
McLellan	O
,	O
who	O
fabricated	O
a	O
nanomotor	B-Algorithm
without	O
developing	O
new	O
methods	O
.	O
</s>
<s>
Nanomotors	B-Algorithm
are	O
the	O
focus	O
of	O
research	O
for	O
their	O
ability	O
to	O
overcome	O
microfluidic	O
dynamics	O
present	O
at	O
low	O
Reynold	O
's	O
numbers	O
.	O
</s>
<s>
Scallop	O
Theory	O
explains	O
that	O
nanomotors	B-Algorithm
must	O
break	O
symmetry	O
to	O
produce	O
motion	O
at	O
low	O
Reynold	O
's	O
numbers	O
.	O
</s>
<s>
In	O
addition	O
,	O
Brownian	O
motion	O
must	O
be	O
considered	O
because	O
particle-solvent	O
interaction	O
can	O
dramatically	O
impact	O
the	O
ability	O
of	O
a	O
nanomotor	B-Algorithm
to	O
traverse	O
through	O
a	O
liquid	O
.	O
</s>
<s>
This	O
can	O
pose	O
a	O
significant	O
problem	O
when	O
designing	O
new	O
nanomotors	B-Algorithm
.	O
</s>
<s>
Current	O
nanomotor	B-Algorithm
research	O
seeks	O
to	O
overcome	O
these	O
problems	O
,	O
and	O
by	O
doing	O
so	O
,	O
can	O
improve	O
current	O
microfluidic	O
devices	O
or	O
give	O
rise	O
to	O
new	O
technologies	O
.	O
</s>
<s>
Now	O
,	O
the	O
more	O
pressing	O
challenge	O
is	O
to	O
overcome	O
issues	O
such	O
as	O
biocompatibility	O
,	O
control	O
on	O
directionality	O
and	O
availability	O
of	O
fuel	O
before	O
nanomotors	B-Algorithm
can	O
be	O
used	O
for	O
theranostic	O
applications	O
within	O
the	O
body	O
.	O
</s>
<s>
In	O
2004	O
,	O
Ayusman	O
Sen	O
and	O
Thomas	O
E	O
.	O
Mallouk	O
fabricated	O
the	O
first	O
synthetic	O
and	O
autonomous	O
nanomotor	B-Algorithm
.	O
</s>
<s>
The	O
two-micron	O
long	O
nanomotors	B-Algorithm
were	O
composed	O
of	O
two	O
segments	O
,	O
platinum	O
and	O
gold	O
,	O
that	O
could	O
catalytically	O
react	O
with	O
diluted	O
hydrogen	O
peroxide	O
in	O
water	O
to	O
produce	O
motion	O
.	O
</s>
<s>
The	O
Au-Pt	O
nanomotors	B-Algorithm
have	O
autonomous	O
,	O
non-Brownian	O
motion	O
that	O
stems	O
from	O
the	O
propulsion	O
via	O
catalytic	O
generation	O
of	O
chemical	O
gradients	O
.	O
</s>
<s>
Joseph	O
Wang	O
in	O
2008	O
was	O
able	O
to	O
dramatically	O
enhance	O
the	O
motion	O
of	O
Au-Pt	O
catalytic	O
nanomotors	B-Algorithm
by	O
incorporating	O
carbon	O
nanotubes	O
into	O
the	O
platinum	O
segment	O
.	O
</s>
<s>
These	O
silver	O
halide	O
and	O
silver-platinum	O
nanomotors	B-Algorithm
are	O
powered	O
by	O
halide	O
fuels	O
,	O
which	O
can	O
be	O
regenerated	O
by	O
exposure	O
to	O
ambient	O
light	O
.	O
</s>
<s>
Some	O
nanomotors	B-Algorithm
can	O
even	O
be	O
propelled	O
by	O
multiple	O
stimuli	O
,	O
with	O
varying	O
responses	O
.	O
</s>
<s>
For	O
example	O
,	O
bimetallic	O
nanomotors	B-Algorithm
have	O
been	O
shown	O
to	O
undergo	O
rheotaxis	O
to	O
move	O
with	O
or	O
against	O
fluid	O
flow	O
by	O
a	O
combination	O
of	O
chemical	O
and	O
acoustic	O
stimuli	O
.	O
</s>
<s>
In	O
Dresden	O
Germany	O
,	O
rolled-up	O
microtube	O
nanomotors	B-Algorithm
produced	O
motion	O
by	O
harnessing	O
the	O
bubbles	O
in	O
catalytic	O
reactions	O
.	O
</s>
<s>
This	O
has	O
limited	O
nanomotors	B-Algorithm
 '	O
in	O
vitro	O
applications	O
.	O
</s>
<s>
Recently	O
titanium	O
dioxide	O
has	O
also	O
been	O
identified	O
as	O
a	O
potential	O
candidate	O
for	O
nanomotors	B-Algorithm
due	O
to	O
their	O
corrosion	O
resistance	O
properties	O
and	O
biocompatibility	O
.	O
</s>
<s>
Future	O
research	O
into	O
catalytical	O
nanomotors	B-Algorithm
holds	O
major	O
promise	O
for	O
important	O
cargo-towing	O
applications	O
,	O
ranging	O
from	O
cell	O
sorting	O
microchip	O
devices	O
to	O
directed	O
drug	O
delivery	O
.	O
</s>
<s>
Recently	O
,	O
there	O
has	O
been	O
more	O
research	O
into	O
developing	O
enzymatic	O
nanomotors	B-Algorithm
and	O
micropumps	O
.	O
</s>
<s>
At	O
low	O
Reynold	O
's	O
numbers	O
,	O
single	O
molecule	O
enzymes	O
could	O
act	O
as	O
autonomous	O
nanomotors	B-Algorithm
.	O
</s>
<s>
This	O
proof-of-concept	O
system	O
demonstrates	O
that	O
enzymes	O
can	O
be	O
successfully	O
utilized	O
as	O
an	O
"	O
engine	O
"	O
in	O
nanomotors	B-Algorithm
and	O
micropumps	O
.	O
</s>
<s>
Developing	O
enzyme-driven	O
nanomotors	B-Algorithm
promises	O
to	O
inspire	O
new	O
biocompatible	O
technologies	O
and	O
medical	O
applications	O
.	O
</s>
<s>
Such	O
nanomotors	B-Algorithm
are	O
not	O
dependent	O
on	O
chemical	O
reactions	O
to	O
fuel	O
the	O
propulsion	O
.	O
</s>
<s>
Recent	O
works	O
have	O
shown	O
how	O
such	O
nanomotors	B-Algorithm
can	O
be	O
used	O
to	O
measure	O
viscosity	O
of	O
non-newtonian	O
fluids	O
at	O
a	O
resolution	O
of	O
a	O
few	O
microns	O
.	O
</s>
<s>
Such	O
nanomotors	B-Algorithm
have	O
been	O
demonstrated	O
to	O
move	O
in	O
blood	O
.	O
</s>
<s>
Recently	O
,	O
researchers	O
have	O
managed	O
to	O
controllably	O
move	O
such	O
nanomotors	B-Algorithm
inside	O
cancer	O
cells	O
allowing	O
them	O
to	O
trace	O
out	O
patterns	O
inside	O
a	O
cell	O
.	O
</s>
<s>
Nanomotors	B-Algorithm
moving	O
through	O
the	O
tumor	O
microenvironment	O
have	O
demonstrated	O
the	O
presence	O
of	O
sialic	O
acid	O
in	O
the	O
cancer-secreted	O
extracellular	O
matrix	O
.	O
</s>
<s>
presented	O
the	O
experimental	O
realization	O
of	O
a	O
prototypical	O
current-driven	O
nanomotor	B-Algorithm
.	O
</s>
<s>
The	O
nanomotor	B-Algorithm
is	O
driven	O
by	O
the	O
electrostatic	O
interaction	O
of	O
the	O
gold	O
leaves	O
with	O
three	O
gate	O
electrodes	O
where	O
alternate	O
currents	O
are	O
applied	O
.	O
</s>
<s>
Some	O
years	O
later	O
,	O
several	O
other	O
groups	O
showed	O
the	O
experimental	O
realizations	O
of	O
different	O
nanomotors	B-Algorithm
driven	O
by	O
direct	O
currents	O
.	O
</s>
<s>
The	O
operation	O
of	O
such	O
nanomotors	B-Algorithm
relies	O
on	O
classical	O
physics	O
and	O
is	O
related	O
to	O
the	O
concept	O
of	O
Brownian	O
motors	O
.	O
</s>
<s>
These	O
examples	O
of	O
nanomotors	B-Algorithm
are	O
also	O
known	O
as	O
molecular	O
motors	O
.	O
</s>
<s>
Due	O
to	O
their	O
small	O
size	O
,	O
quantum	O
mechanics	O
plays	O
an	O
important	O
role	O
in	O
some	O
nanomotors	B-Algorithm
.	O
</s>
<s>
showed	O
the	O
cross-over	O
from	O
classical	O
motion	O
to	O
quantum	O
tunneling	O
in	O
a	O
nanomotor	B-Algorithm
made	O
of	O
a	O
rotating	O
molecule	O
driven	O
by	O
the	O
STM	O
's	O
current	O
.	O
</s>
<s>
Finally	O
,	O
reverse	O
quantum	O
pumping	O
has	O
been	O
proposed	O
as	O
a	O
general	O
strategy	O
towards	O
the	O
design	O
of	O
nanomotors	B-Algorithm
.	O
</s>
<s>
In	O
this	O
case	O
,	O
the	O
nanomotors	B-Algorithm
are	O
dubbed	O
as	O
adiabatic	O
quantum	O
motors	O
and	O
it	O
was	O
shown	O
that	O
the	O
quantum	O
nature	O
of	O
electrons	O
can	O
be	O
used	O
to	O
improve	O
the	O
performance	O
of	O
the	O
devices	O
.	O
</s>
