| Konjac glucomannan(KGM)is a type of natural macromolecule material with fine degradation and film forming characteristic,the film of KGM has good mechanical property. Collagen protein(COL),which has good biological characteristics,is the main structural protein in bodies of human beings and vertebrates.But COL is mechanically weak and easy to biodegrade.Chitosan(CS)is a kind of natural polymer which has good biocompatibility and biodegradability.Therefore,COL/KGM and CS/KGM blend films were studied for improving the properties of materials used in pure state and achieving applications of these composite materials in tissue engineering.Firstly,the COL/KGM blend films were prepared by solvent-casting method.Glycerin was used as additive and ammonia for adjusting pH.The COL/KGM blend liquid was prepared under virgous agitation.Stirring was continued for 40mins to obtain a homogeneous polymer solution,vaccum defoamer was performed in -0.08MPa,the solution was cast in the glass mold, kept subsequently at 60℃for 8-9h.The optimized process conditions were investigated by orthogonal method.The crystallography structure,the chemical bond structure and microstructure of the blend films were characterized by XRD,IR and optics microscope. Meanwhile,the mechanical properties(tensile strength,elongation rate),water absorptivity, water vapor permeability,and the transmittance of the blend films were investigated.Tensile strength and elongation rate of samples was 8～13MPa and 11～18%in the orthogonal experiment.We studied characteristics of the blend film in optimal group.IR results showed there was a certain effect of hydrogen bonding and the characteristics group-acetyl of the KGM was removed,the blend film presented weak gel state;transmittance and microstructure analyses showed that blend film had good compatibility;the water absorptivity of the blend films was large because it would dissolved when dipped in water about 2h.The water vapor permeability of samples with different KGM content was also investigated,the water vapor permeability was 1.9～2.5g.mil/day.m~2.Pa,and increased with the increase of the KGM content.Secondly,the preparation of the CS/KGM blend films was investigated.Chitosan was dissolved with acetic acid.The blend liquid was prepared under vigorous agitation.Stirring was continued for 40rains to obtain a homogeneous polymer solution,vaccum defoamer was performered in -0.08MPa,the solution was cast in the glass mold,kept subsequently at 60℃for 8-9h.Blend films were dipped in with NaOH solution,and then dried in air.The influence of different CS content and alkali processing time on the mechanical properties,water absorptivity,water vapor permeability,transmittance,the rate of degradation was studied.The crystallography structure,the chemical bond structure and microstructure of the blend films were characterized by XRD,IR and optics microscope.The biocompatibility of the CS/KGM blend film was verified by co-culturing with bone marrow-derived mesenchymal stem cells in vitro.The results showed that tensile strength of the blend films was 20～45MPa and the elongation rate was 5～9%;tensile strength increased and elongation rate decreased with increase of the CS content,tensile strength was higher and elongation rate was lower when blend films were processed in alkali solution for 4h than that for 2h;water absorptivity was 150～290%,which increased with the increase of the content of CS and alkali processing time; water vapor permeability was 1.7～3.0 g.mil/day.m~2.pa,which reduced with the increase of the CS content and alkali processing time;IR results showed there was strong hydrogen bond effect between CS and KGM;XRD results showed the blend film presented a noncrystalline state;transmittance and microstructure analyses showed that COL/KGM blend films had good compatibility;the biodegradation rate reduced with the increase of the CS content and alkali processing time;the blend film had excellent stem cells affinity and biocompatibility, the cells presented death phenomenon to a certain extent with the increasing concentration of NaOH solution. |
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