|Institution:||University of Akron|
|Keywords:||Biomedical Engineering; Polymers; PLGA and pseudowollastonite composite, porous scaffold, osteogenic|
|Full text PDF:||http://rave.ohiolink.edu/etdc/view?acc_num=akron1397041385|
The goal of this study was to develop an optimal porous composite scaffold, composed of pseudowollastonite (psw; beta-CaSiO3), and poly(L,D-lactic-co-glycolic acid) (PLGA). In culture medium, the psw released Ca2+ and soluble silica, which are osteoinductive soluble factors. PLGA was utilized as a structural framework and to maintain pH of the scaffold. Scaffolds were prepared by solvent casting/particle leaching technique to obtain porosity and interconnectivity of pores. The mass of NaCl, psw and PLGA were adjusted to determine the effects of the different components on the scaffold's biocompatibility and osteoinductive potential, in vitro, on two types of cells, hMSC (human Mesenchymal Stem Cells) and MC3T3 (murine osteoblast precursor cells). An orthogonal study was designed for 9 scaffold compositions. Scanning electron microscopy and micro-computed tomography showed that the scaffold pore structure depended on the amount of NaCl used during fabrication. Variable porosity, and hydrolysis of the psw and PLGA components resulted in pH changes and different released soluble silica concentrations. Total DNA analysis from cell culture in growth medium showed that scaffold compositions which resulted in a small pH shift (+/- 0.5 on Day 3) and low soluble silica concentration (65 +/- 3 ppm) were less cytotoxic than scaffolds for which pH changes were large (+/- 1.2 on Day 3) and soluble silica concentrations were high (87 +/- 5 ppm). The viability of hMSCs was lower than that of MC3T3 under the same set of conditions. The hMSCs were incubated on each scaffold surface for 28 days in osteogenic induction medium and alkaline phosphatase staining was used as a preliminary estimate of osteoinductivity of scaffolds. Two scaffold compositions, which showed lower cytotoxicity and higher osteoinductivity than the other compositions, were selected for LIVE/DEAD® staining. Better cell morphology and attachment was observed for the scaffold composed of low NaCl, intermediate psw and intermediate PLGA contents, compared to the scaffold of intermediate NaCl, intermediate psw and high PLGA content. Thus, the optimum psw-PLGA scaffold composition was determined for cell attachment, viability and a preliminary estimate of osteoinduction.