Sugar‐mediated chitosan/poly(ethylene glycol)‐β‐dicalcium pyrophosphate composite: Mechanical and microstructural properties

Abstract The microstructural and mechanical properties of sugar‐mediated chitosan/poly(ethylene glycol)‐based scaffolds and composites, which are composed of β‐dicalcium pyrophosphate (β‐DCP) and sugar‐mediated scaffolds, were investigated. All of the scaffolds were prepared by various freeze‐drying protocols. The differences in the freeze‐drying process of the sugar‐mediated chitosan/poly(ethylene glycol) scaffold for three types of sugar (sucrose, glucose, and D‐fructose) were determined by scanning electron microscopic observation, water retention, density, and porosity analyses. The sugar‐mediated scaffolds prepared by scheme I of the freeze‐drying process show large pores, poorly connective interlayers, and disintegrated inner structures, different from the small pores and well‐connective channel structures as shown in the scheme II freeze‐drying process. The key factors for controlling pore structure and size in the scheme I freeze‐drying process were formulation and composition, but for the scheme II freeze‐drying process, the key factor was freeze protocol. The composite scaffolds were macroporous, and the microstructure changed considerably with added β‐DCP content. The incorporation of β‐DCP granules caused a significant enhancement of compressive modulus and yield strength. The increased mechanical strength may be attributable not only to the physical complexation between the sugar‐mediated scaffold and β‐DCP, but also the chemical reaction to apatite formed on the cell wall. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 262–272, 2003