posted on 2017-03-23, 00:00authored byYashira
M. Zayas-Gonzalez, Benjamín J. Ortiz, David M. Lynn
We report the reactive
layer-by-layer assembly of amine-reactive
polymer multilayers using an azlactone-functionalized polymer and
small-molecule diamine linkers. This approach yields cross-linked
polymer/linker-type films that can be further functionalized, after
fabrication, by treatment with functional primary amines, and provides
opportunities to incorporate other useful functionality that can be
difficult to introduce using other polyamine building blocks. Films
fabricated using poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) and three
model nondegradable aliphatic diamine linkers yielded reactive thin
films that were stable upon incubation in physiologically relevant
media. By contrast, films fabricated using PVDMA and varying amounts
of the model disulfide-containing diamine linker cystamine were stable
in normal physiological media, but were unstable and eroded rapidly
upon exposure to chemical reducing agents. We demonstrate that this
approach can be used to fabricate functionalized polymer microcapsules
that degrade in reducing environments, and that rates of erosion,
extents of capsule swelling, and capsule degradation can be tuned
by control over the relative concentration of cystamine linker used
during fabrication. The polymer/linker approach used here expands
the range of properties and functions that can be designed into reactive
PVDMA-based coatings, including functionality that can degrade, erode,
and undergo triggered destruction in aqueous environments. We therefore
anticipate that these approaches will be useful for the functionalization,
patterning, and customization of coatings, membranes, capsules, and
interfaces of potential utility in biotechnical or biomedical contexts
and other areas where degradation and transience are desired. The
proof of concept strategies reported here are likely to be general,
and should prove useful for the design of amine-reactive coatings
containing other functional structures by judicious control of the
structures of the linkers used during assembly.