Study on the diffusion model of calcium-alginate microbeads
Yao LS., Liu TQ., Li XQ., Ge D., Cui ZF., Ma XH.
Calcium-Alginate Microbeads (Ca-Alg MBs) has got more and more wide applications in bioengineering fields recently. In order to culture animal cells in Ca-Alg MBs and to provide the optimum growth conditions for the cells, the diffusivity (D) and the favorable diameter of Ca-Alg MBs used should be determined. A model of diffusive mass transfer in the gel bead was established for the study of the relationship between the diameter or the inner pore structure of Ca-Alg MBs and the diffusivity. Firstly, Ca-Alg MBs of different diameters were prepared through a high-voltage electrostatic droplet generator. Then, the diffusive experiments were conducted to get the diffusive data of glucose in Ca-Alg MBs with different diameters. After that, a diffusive mathematical model was set up to find the diffusivity of glucose in Ca-Alg MBs by fitting the experimental data. And then, the diffusivity in Ca-Alg MBs with different diameters was calculated. Both the experimental results and the model calculations show that the diffusivity increases with the diameter of the Ca-Alg MBs, and the mechanism of this phenomenon was discussed. On the premises of selecting the Ca-Alg MBs with higher diffusivity and combining with the requirement of the animal cell culture, it is proposed that the proper diameter of Ca-Alg MBs used for animal cell culture should be 2 mm or so.