Characterization of Cationic Polymers by Asymmetric Flow Field-Flow Fractionation and Analytical Ultracentrifugation
-
Wagner, Michael; Pietsch, Christian; Tauhardt, Lutz; Träger, Anja; Schubert, Ulrich S.
- Abstract:
- In
the
field
of
nanomedicine,
cationic
polymers
are
the
subject
of
intensive
research
and
represent
promis-
ing
carriers
for
genetic
material.
The
detailed
characterization
of
these
carriers
is
essential
since
the
efficiency
of
gene
delivery
strongly
depends
on
the
properties
of
the
used
polymer.
Common
character-
ization
methods
such
as
size
exclusion
chromatography
(SEC)
or
mass
spectrometry
(MS)
suffer
from
problems,
e.g.
missing
standards,
or
even
failed
for
cationic
polymers.
As
an
alternative,
asymmetrical
flow
field-flow
fractionation
(AF4)
was
investigated.
Additionally,
analytical
ultracentrifugation
(AUC)
and
1
H
NMR
spectroscopy,
as
well-established
techniques,
were
applied
to
evaluate
the
results
obtained
by
AF4.
In
this
study,
different
polymers
of
molar
masses
between
10
and
120
kg
mol
−
1
with
varying
amine
functionalities
in
the
side
chain
or
in
the
polymer
backbone
were
investigated.
To
this
end,
some
of
the
most
successful
gene
delivery
agents,
namely
linear
poly(ethylene
imine)
(LPEI)
(only
secondary
amines
in
the
backbone),
branched
poly(ethylene
imine)
(B-PEI)
(secondary
and
tertiary
amino
groups
in
the
backbone,
primary
amine
end
groups),
and
poly(
l
-lysine)
(amide
backbone
and
primary
amine
side
chains),
were
characterized.
Moreover,
poly(2-(dimethylamino)ethyl
methacrylate)
(PDMAEMA),
poly(2-
(amino)ethyl
methacrylate)
(PAEMA),
and
poly(2-(
tert
-butylamino)ethyl
methacrylate)
(P
tBAEMA
)
as
polymers
with
primary,
secondary,
and
tertiary
amines
in
the
side
chain,
have
been
investigated.
Reliable
results
were
obtained
for
all
investigated
polymers
by
AF4.
In
addition,
important
factors
for
all
meth-
ods
were
evaluated,
e.g.
the
influence
of
different
elution
buffers
and
AF4
membranes.
Besides
this,
the
correct
determination
of
the
partial
specific
volume
and
the
suppression
of
the
polyelectrolyte
effect
are
the
most
critical
issues
for
AUC
investigations.
- Year:
- 2014
- Type of Publication:
- Article
- Journal:
- Journal of Chromatography A
- Volume:
- 1325
- Pages:
- 195 - 203