Properties and structure variations of degradable fiber/calcium phosphate cement composite under similar physiological conditions

The in vitro mechanical properties,  the in vivo degradation rate,  the phase composition, and microstructure of degradable polylactic-co-glycolic acid (PLGA) fibre/calcium phosphate cement (F-CPC) composite at various immersion (or implantation) stages were investigated by using in vitro physiological saline immersion and in vivo rabbit muscle implantation，respectively. The in vitro immersion results show that at the initial immersion stages，the addition of degradation fibres decreases the compressive strength of the composite but slightly improves its flexural strength and significantly increases its fracture toughness by two orders of magnitude. After being subjected to a long-time immersion，the compressive strength，flexural strength and fracture toughness  of the composite decrease uniformly. The in vivo implant results show that the addition of the degradable fibres promotes the degradation of the composite and also the increase amplitude at the degradation rate is gradually enlarged by further extending the implant time. The variations in these properties of the composite have a strong relationship with the fibre degradation behaviour and composite microstructure.