%0 Journal Article %A Jijun Huang %A Dacheng Zhao %A Smit J Dangaria %A Xianghong Luan %A Thomas G.H Diekwisch %A Guoqing Jiang %A Eduardo Saiz %A Gao Liu %A Antoni P Tomsia %B Polymer %D 2013 %G eng %N 2 %P 909-919 %R 10.1016/j.polymer.2012.12.017 %T Combinatorial design of hydrolytically degradable, bone-like biocomposites based on PHEMA and hydroxyapatite %V 54 %8 01/2013 %@ 0032-3861 %X

With advantages such as design flexibility in modifying degradation, surface chemistry, and topography, synthetic bone-graft substitutes are increasingly demanded in orthopedic tissue engineering to meet various requirements in the growing numbers of cases of skeletal impairment worldwide. Using a combinatorial approach, we developed a series of biocompatible, hydrolytically degradable, elastomeric, bone-like biocomposites, comprising 60 wt% poly(2-hydroxyethyl methacrylate-co-methacrylic acid), poly(HEMA-co-MA), and 40 wt% bioceramic hydroxyapatite (HA). Hydrolytic degradation of the biocomposites is rendered by a degradable macromer/crosslinker, dimethacrylated poly(lactide-b-ethylene glycol-b-lactide), which first degrades to break up 3-D hydrogel networks, followed by dissolution of linear pHEMA macromolecules and bioceramic particles. Swelling and degradation were examined at Hank's balanced salt solution at 37 degrees C in a 12-week period of time. The degradation is strongly modulated by altering the concentration of the co-monomer of methacrylic acid and of the macromer, and chain length/molecular weight of the macromer. 95% weight loss in mass is achieved after degradation for 12 weeks in a composition consisting of HEMA/MA/Macromer = 0/60/40, while 90% weight loss is seen after degradation only for 4 weeks in a composition composed of HEMA/MA/Macromer = 27/13/60 using a longer chain macromer. For compositions without a co-monomer, only about 14% is achieved in weight loss after 12-week degradation. These novel biomaterials offer numerous possibilities as drug delivery carriers and bone grafts particularly for low and medium load-bearing applications. (C) 2012 Elsevier Ltd. All rights reserved.