In-vitro Degradation and Bioactivity of Tailored Amorphous Multi Porous Scaffold Structure


  • Paper presented at Bangalore INDIA BIO 2011 Conference
  • This work was supported by the Process Chemistry Centre, a National Centre of Excellence of the Academy of Finland, and National Science Foundation (DMR-0602975 and DMR-0844014) of United States.

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A key requirement for the use of bio scaffold is that its degradation rate matches the growth rate of target tissue. Therefore, the degradation of recently developed tailored amorphous multiporous (TAMP) scaffold of 70SiO2·30CaO (mol%) in simulated body fluid (SBF) was studied under both static and quasi-dynamic conditions. The degradation was assessed through the dissolution of silica from the glass into SBF, while the in-vitro bioactivity was characterized by precipitation of calcium phosphate (CaP) on and inside the scaffold. Under static conditions, the degradation stopped due to the saturation of solution with silica in 3 days, whereas the precipitation of CaP continued. Rapid degradation and better in-vitro bioactivity was found under quasi-dynamic conditions, where the concentration gradient across the sample was maintained. The degradation followed exponential dependence on time with a half-life of 15.4 days and initial degradation rate 4.5% day−1. The remaining samples maintained their integrity and pore structure during degradation. The degradation occurred in three distinct stages: (a) wetting stage, (b) initial degradation stage when CaP precipitation dominates, and (c) intensive degradation stage when the nanopores rupture and network dissolves. By varying the sintering parameters the nanopore structure, and hence the degradation rate, can be tailored to suit the anticipated tissue regeneration rate. With demonstrated rapid and controllable degradation and good in-vitro bioactivity, the TAMP scaffold shows promise as candidate for bone regeneration application under various conditions in the body.