Phosphonate-functionalized poly(β-amino ester) macromers as potential biomaterials.

Biodegradability, hemocompatibility, resistance to protein adsorption, and strong interactions with hydroxyapatite (HAP)-based tissues such as dentin, enamel, and bone are important properties of phosphorus-containing biomaterials. Here, novel phosphonate-functionalized poly(β-amino ester) (PBAE) macromers are synthesized through aza-Michael addition of various diacrylates [1,6-hexanediol diacrylate (HDDA), poly(ethylene glycol) diacrylate (PEGDA, M  = 575), 1,4-butanediol diacrylate (BDDA), 1,6-hexanediol ethoxylate diacrylate (HDEDA) and triethylene glycol diacrylate (TEGDA)] and a phosphonate-containing primary amine (diethyl 2-aminoethylphosphonate, A1) efficiently without any catalyst; where replacement of A1 with propyl amine (PA) served as control. The macromers, whose molecular weight is ca. 1000-4000 Da as confirmed by both GPC and H-NMR spectroscopy, are photopolymerized to give biodegradable gels. The degradation behavior and cell interaction of these gels are studied. The degradation rates of the gels can be varied by choice of starting acrylates and the acrylate:amine ratio. Furthermore, the gels showed slightly higher degradability than PA-based analogs (controls). Except TEGDA and PEGDA-based ones, all phosphonate-functionalized PBAE gels supported the attachment of larger number of SaOS-2 cells than nonphosphonated ones and the best film was found to be the one based on HDEDA-A1 with balanced hydrophilicity. Degradation products of these films have no significant cytotoxicity except HDDA-PA. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1390-1399, 2018.