Preparation and characterization of bacterial cellulose sponge with hierarchical pore structure as tissue engineering scaffold

Bacterial cellulose (BC) is believed to be a promising and cost-efficient nano-scaffold for tissue engineering. However, the pore size of BC is not big enough for cell ingrowth, which restricts its practical usage as tissue engineering scaffold. In this work, novel porous BC sponges were obtained through emulsion freeze-drying technique. Results of scanning electron microsc.opy (SEM) and mercury intrusion porosimeter showed that the resulted BC sponges were composed of nanofibrills with hierarchical pore structure consisting of large pores (from 20 to similar to 1,000 mu m in diameter) and nano pores (down to similar to 4 nm in diameter). BC sponges possessed high surface area (92.81 +/- 2.02 m(2)/g) and sufficient porosity (90.42 +/- 0.24%). Additionally, the size and shape of BC sponges could be easily controlled by using appropriate molds. We also demonstrated that BC sponges had excellent cell compatibility as fibrous synovium-derived mesenchymal stem cells (MSCs) could proliferate well on and inside the BC sponges and the maximum ingrowth distance was 150 mu m after cultured for 7 days.