Biodegradable poly(propylene fumarate)(PPF) was synthesized by a two-step method

which was then copolymerized with N -vinyl pyrrolidone(NVP) in 1

4-dioxane to fabricate PPF hydrogels.By changing the relative contents of monomers and solvent

hydrogels with different swelling property and mechanical strength were obtained.Generally

with a larger volume of solvent the hydrogel had a larger swelling ratio but a smaller compressive modulus due to the existence of pores in the matrix.Considering the balance between the hydrogel swelling and mechanical strength

a composite hydrogel with a macroporous structure was further fabricated by mixing 30% PPF and NVP

3% hydroxyapatite(HA) nanoparticles and benzoyl peroxide in 1

4-dioxane

following by casting the mixture into NaCl particles(280~450 m as porogens)

polymerization and removal of porogens.Addition of the HA particles increased the compressive modulus of porous hydrogels by 61%.Due to the sufficient exposure of the pre-loaded HA nucleation seeds and the good ability of medium exchange

significantly faster apatite growth was found in the composite macroporous hydrogel after being incubated in simulated body fluid

demonstrating that the PPF-NVP/HA macroporous hydrogel has better bone formation activity than the pure PPF-NVP macroporous hydrogel.