Modification And Properties Of Bacterial Cellulose Tissue Engineering Scaffolds

Cancer is the one of greatest threat to human health. In order to prevent and curecancer, it is very necessary to fully study the formation, proliferation anddifferentiation of tumor cells. Therefore, many scholars began to study tissueengineering scaffold used for culturing of tumor cells in vitro. Collagen scaffolds arewidely used in clinic at present. Although collagen scaffolds have goodbiocompatibility, they are quite expensive. Therefore, preparation of a new type oftumor scaffold is very important. Bacterial cellulose (BC) with ECM-likethree-dimensional network structure, good mechanical properties and biodegradabilityis considered to be an ideal material for tissue engineering scaffold Bacterial cellulose(BC) as a potential new biomedical scaffolds However, as a polymeric polysaccharide,BC lacks biological activity and large holes which is necessary for nutrition transportand waste emissions. Therefore, an ideal BC scaffold with surface modification andstructural modulation is highly demanded.In order to improve the bioactivity of BC, lecithin (Lec) was immobilized on thesurface of BC nanofiber via chemical crosslinking method. SEM, XRD, FTIR, contactangle, TGA and DMA were utilized to analyze the micro structures, crystallinestructures, chemical structures, wettability, thermal properties and dynamicmechanical properties of the nanocomposites. SEM results showed that, when theconcentration of the Lecithin solution was2%, a homogeneous lecithin layer wasformed and enwrapped the surface of BC fibers. And the composites possessed athree-dimensional network structure similar to origin BC. Furthermore, the BC/Leccomposites had good hydrophilicity, high thermal and mechanical properties, whichwas beneficial to their further applications. In addition, the BC/Lec compositesscaffolds were cultured in vitro with breast cancer cell lines MDA-MB-231(231cell)and MCF-7to evaluate their bioactivity. The results showed that BC/Lec compositescaffolds were non-toxic and their biological activity was improved significantly.Aiming to explore a more effective way to improve the bioactivity of BC scaffold,the BC was also modified by the collagen. In order to better mimic the organization ofextracellular matrices with hierarchical pore structure including large pores and nanopores, laser drilling strategy were explored to introduce parallel-channel arrays into BC membranes (pBC) which were further modified by the collagen. SEM, FTIR,contact angle, TGA and DMA were conducted to compare BC/Col nanocompositeswith pBC/Col nanocomposites. The SEM and FTIR results showed that the BC/Coland pBC/Col composites material had a very similar structure and properties. Andbecause of the presence of parallel-channel arrays, the latter could absorb more Colmolecules. The dynamic mechanical analysis results showed that BC/Col andpBC/Col composites possessed high mechanical properties. Since the laser drillingtechnique destroyed structure of BC fibers to some extent, the mechanical propertiesof the latter were slightly decreased. However, they still exhibited a storage modulusas high as7000MPa, which could sufficiently meet the requirements for practicalapplications. The biological results confirmed that pBC/Col was more suitable for celladhesion and proliferation than BC/Col scaffolds and pure BC. And the cells can growinto the interior of scaffolds by migrating along the inner wall of micropores.