Selection of Pluronic F-127 hydrogel’s optimum concentration and tests of its biocompatibility

Abstract

Objective To determine the physical and chemical properties of Pluronic F-127 hydrogel and select its optimum concentration. At the same time, its biocompatibility was detected as the carrier of bone marrow mesenchymal stem cells (BMSCs). Methods 10%, 20%, 30% (m/v) Pluronic F-127 hydrogel were prepared, test its gelling properties and swelling kinetics. The structures of hydrogel with different concentrations were observed under scanning electron microscopy (SEM). Different concentrations of hydrogels were grouped and co-cultured for 7 days after containing BMSCs and transforming growth factor-β1 (TGF-β1). The proliferation and growth status of BMSCs in each group were detected by Cell counting kit-8 (CCK-8) method. After these above research, the most appropriate concentration of Pluronic F-127 hydrogel was chosen. Then, the inducer or growth factor was added to induce multi-directional differentiation of BMSCs. The Oil Red-O Staining and Alizarin red-S staining were conducted respectively. The above results were used to comprehensively evaluate the induced differentiation of cells in the vector. Results The gelation time of Pluronic F-127 hydrogel is inversely proportional to its concentration. With a higher the concentration, the lower the initial gelation temperature and the easier gelation. The higher concentration of Pluronic F-127 hydrogel, its microstructure became denser and the corresponding swelling rate was lower. CCK-8 results confirmed that compared with 20% Concentration, 30% hydrogel had a more obvious effect on the inhibition of proliferation of BMSCs. On day 5, opitical density (A) of 20% group (0.302±0.045) was significantly lower than 10% group (0.571±0.081). (t=5.120, P<0.05), while after adding the TGF-β1 to the gel carrier, it promoted the proliferation of cells. Most obviously, 20% group (using TGF-β1) (0.454±0.034) enhanced cell proliferation significantly better than 20% group (0.302±0.045) on day 5 (t=6.088, P<0.05). After adipogenic and osteogenic induction, the lipid droplets and calcification components were stained under the microscope. Conclusion 20% Concentration of Pluronic F-127 can be used as a suitable carrier to support the proliferation and differentiation of BMSCs, and the addition of growth factors or inducing fluids is more conducive to further cell growth or differentiation. Pluronic F-127 hydrogel is promising to have great value in tracheal transplantation experiments as a new type of cell carrier. Key words: Pluronic F-127 hydrogel; Bone marrow stem cells; Tracheal tissue engineering; Biocompatibility