For initial
experiments, LbL-assembled films of poly(allylamine hydrochloride)
(PAH) and poly(acrylic acid) (PAA) were assembled on glass slides
as previously described, adjusting the pH to control the mechanical
stiffness as defined by E.17 (link) Because the average layer thickness is inversely proportional to
pH, films built from polymer solutions of pH 2.0 and 4.0 went through
a total of 11 and 15 dipping cycles, respectively, in order to maintain
a constant film thickness.8 (link) To complete
one LbL assembly cycle, glass slides were dipped into a 10 mM solution
of PAH for 30 min, followed by three rinse–bath dippings for
2, 1, and 1 min in DI H2O and then were dipped into a 10
mM solution of PAA for 30 min, followed by the same three-bath rinse.
The films were then coated with solutions of 100 μg/mL collagen
I (BD Biosciences) or 100 μg/mL collagen I and 25 μg/mL
lumican (R&D Systems, Inc.) for 2 to 3 h at 37 °C. LbL assemblies
are typically described by the cation/anion pair and total number
of bilayers For example, (PAH/PAA)n indicates
an assembly of n bilayers composed of one layer of
PAH followed by one layer of PAA.
experiments, LbL-assembled films of poly(allylamine hydrochloride)
(PAH) and poly(acrylic acid) (PAA) were assembled on glass slides
as previously described, adjusting the pH to control the mechanical
stiffness as defined by E.17 (link) Because the average layer thickness is inversely proportional to
pH, films built from polymer solutions of pH 2.0 and 4.0 went through
a total of 11 and 15 dipping cycles, respectively, in order to maintain
a constant film thickness.8 (link) To complete
one LbL assembly cycle, glass slides were dipped into a 10 mM solution
of PAH for 30 min, followed by three rinse–bath dippings for
2, 1, and 1 min in DI H2O and then were dipped into a 10
mM solution of PAA for 30 min, followed by the same three-bath rinse.
The films were then coated with solutions of 100 μg/mL collagen
I (BD Biosciences) or 100 μg/mL collagen I and 25 μg/mL
lumican (R&D Systems, Inc.) for 2 to 3 h at 37 °C. LbL assemblies
are typically described by the cation/anion pair and total number
of bilayers For example, (PAH/PAA)n indicates
an assembly of n bilayers composed of one layer of
PAH followed by one layer of PAA.
