Multilayered Thin Films from Boronic Acid-Functional Poly(amido amine)s

Abstract

PurposeTo investigate the properties of phenylboronic acid-functional poly(amido amine) polymers (BA-PAA) in forming multilayered thin films with poly(vinyl alcohol) (PVA) and chondroitin sulfate (ChS), and to evaluate their compatibility with COS-7 cells.MethodsCopolymers of phenylboronic acid-functional poly(amido amine)s, differing in the content of primary amine (DAB-BA-PAA) or alcohol (ABOL-BA-PAA) side groups, were synthesized and applied in the formation of multilayers with PVA and ChS. Biocompatibility of the resulting films was evaluated through cell culture experiments with COS-7 cells grown on the films.ResultsPVA-based multilayers were thin, reaching ~100 nm at 10 bilayers, whereas ChS-based multilayers were thick, reaching ~600 nm at the same number of bilayers. All of the multilayers are stable under physiological conditions in vitro and are responsive to reducing agents, owing to the presence of disulfide bonds in the polymers. PVA-based films were demonstrated to be responsive to glucose at physiological pH at the investigated glucose concentrations (10–100 mM). The multilayered films displayed biocompatibility in cell culture experiments, promoting attachment and proliferation of COS-7 cells.ConclusionsResponsive thin films based on boronic acid functional poly(amido amine)s are promising biocompatible materials for biomedical applications, such as drug releasing surfaces on stents or implants.Graphical AbstractLayer-by-Layer Assembly

Multilayered Thin Films from Boronic Acid-Functional Poly(amido amine)s As Drug-Releasing Surfaces

“…Incorporation of ARS proved to be more efficient in the ABOL-BA-PAA multilayers than in the DAB-BA-PAA multilayers. This is in contrast to the previous study showing that DAB-BA-PAA facilitated deposition of ChS and resulted in overall thicker films, as compared to ABOL-BA-PAA ( 21 ). However, this study was based on the absorbance specific to ChS (at 258 nm) and therefore did not provide information on the amount of incorporated BA-PAA polymer.…”

“…Also, since the release was only followed by the decrease in ARS absorbance in the multilayers, it is not deducible from these results whether or not also BA-PAA polymers or ChS were released during the initial release phase. Our previous results with ARS-free multilayers showed that up to ~20% of the polymeric components of the multilayers were also released within 2 h of incubation under the same conditions ( 21 ). Therefore, the release observed in Fig.…”

“…We previously reported the syntheses of two branched boronic acid-functionalized poly(amido amine)s (BA-PAAs) ( 21 ). The degrees of BA functionalization of the two BA-PAAs were similar at ~50%, with branching estimated to be ~10 and ~30% for DAB-BA-PAA and ABOL-BA-PAA, respectively, and number average molecular weights of 12 and 14 kg/mol, respectively.…”

“…Figure 1 shows build-up profiles of DAB-BA-PAA-(ChS + ARS#DAB-BA-PAA) 10 and ABOL-BA-PAA-(ChS + ARS#ABOL-BA-PAA) 10 based on increases in absorbance at 470 nm. Incorporation of the dark red ARS drastically changes the spectral properties of the films, which complicates relating the UV spectra of these films with previous ARS-free multilayers ( 21 ). As the ARS is the reporter molecule for the investigation of both loading and release, and no multilayer build-up was observed in the absence of ChS, it was deemed appropriate to study the film behavior based on the UV-absorption of ARS.…”

“…Previously, we reported the preparation and properties of multilayered systems prepared from boronic acid-containing poly(amido amine)s (BA-PAA) and chondroitin sulfate (ChS) ( 21 ). Multilayer build-up of these films proceeds through electrostatic interactions, mainly through the positively-charged BA-PAA polymer chains and the negatively-charged sulfate-containing ChS.…”