The aim of the present study was to compare one-step method to EDC/NHS crosslinking （EDC/NHS group） and one-step simultaneous method to EDC/NHS crosslinking and heparin immobilization （EDC/NHS- Heparin group） in i...The aim of the present study was to compare one-step method to EDC/NHS crosslinking （EDC/NHS group） and one-step simultaneous method to EDC/NHS crosslinking and heparin immobilization （EDC/NHS- Heparin group） in improving physiochemical and biological properties of native collagen sponge （Control group）. Modified collagen sponge overcome the disadvantages of native collagen sponge. IR spectra suggest the change of the functional groups. DSC data indicate that the stability of caloric transformation in EDC/NHS group is slightly higher than that of EDC/NHS-Heparin group. The crosslinking degree, stability against enzymes, stability in morphologically and biomechanical properties of EDC/NHS-Heparin group are higher than those of EDC/NHS group, whereas, the water-binding capacity in EDC/NHS-Heparin group is lower than that of EDC/NHS group. HUVECs in EDC/NHS-Heparin group scaffold proliferate fast, migrate well and distribute uniformly. One-step simultaneous method gains the better effects in above aspects, heparinized collagen matrices increase in angiogenic potential and suit for defect repairing and tissue engineering.展开更多
Tissue engineering response may be tailored via controlled,sustained release of active agents from protein-loaded degradable microparticles incorporated directly within three-dimensional(3D)ice-templated collagen scaf...Tissue engineering response may be tailored via controlled,sustained release of active agents from protein-loaded degradable microparticles incorporated directly within three-dimensional(3D)ice-templated collagen scaffolds.However,the effects of covalent crosslinking during scaffold preparation on the availability and release of protein from the incorporated microparticles have not been explored.Here,we load 3D ice-templated collagen scaffolds with controlled additions of poly-(DL-lactide-co-glycolide)microparticles.We probe the effects of subsequent N-(3-dimethylaminopropyl)-N0-ethylcarbodiimide hydrochloride crosslinking on protein release,using microparticles with different internal protein distributions.Fluorescein isothiocyanate labelled bovine serum albumin is used as a model protein drug.The scaffolds display a homogeneous microparticle distribution,and a reduction in pore size and percolation diameter with increased microparticle addition,although these values did not fall below those reported as necessary for cell invasion.The protein distribution within the microparticles,near the surface or more deeply located within the microparticles,was important in determining the release profile and effect of crosslinking,as the surface was affected by the carbodiimide crosslinking reaction applied to the scaffold.Crosslinking of microparticles with a high proportion of protein at the surface caused both a reduction and delay in protein release.Protein located within the bulk of the microparticles,was protected from the crosslinking reaction and no delay in the overall release profile was seen.展开更多
基金Funded by the National Natural Science Foundation of China (10832012)the Natural Science Foudation of Tianjin city(08JCYBJC03400)
文摘The aim of the present study was to compare one-step method to EDC/NHS crosslinking （EDC/NHS group） and one-step simultaneous method to EDC/NHS crosslinking and heparin immobilization （EDC/NHS- Heparin group） in improving physiochemical and biological properties of native collagen sponge （Control group）. Modified collagen sponge overcome the disadvantages of native collagen sponge. IR spectra suggest the change of the functional groups. DSC data indicate that the stability of caloric transformation in EDC/NHS group is slightly higher than that of EDC/NHS-Heparin group. The crosslinking degree, stability against enzymes, stability in morphologically and biomechanical properties of EDC/NHS-Heparin group are higher than those of EDC/NHS group, whereas, the water-binding capacity in EDC/NHS-Heparin group is lower than that of EDC/NHS group. HUVECs in EDC/NHS-Heparin group scaffold proliferate fast, migrate well and distribute uniformly. One-step simultaneous method gains the better effects in above aspects, heparinized collagen matrices increase in angiogenic potential and suit for defect repairing and tissue engineering.
基金the European Research Council[ERC Advanced Grant 3205983D-E]the Medical Research Council,Arthritis Research UK,Reumafonds and the UKRMP。
文摘Tissue engineering response may be tailored via controlled,sustained release of active agents from protein-loaded degradable microparticles incorporated directly within three-dimensional(3D)ice-templated collagen scaffolds.However,the effects of covalent crosslinking during scaffold preparation on the availability and release of protein from the incorporated microparticles have not been explored.Here,we load 3D ice-templated collagen scaffolds with controlled additions of poly-(DL-lactide-co-glycolide)microparticles.We probe the effects of subsequent N-(3-dimethylaminopropyl)-N0-ethylcarbodiimide hydrochloride crosslinking on protein release,using microparticles with different internal protein distributions.Fluorescein isothiocyanate labelled bovine serum albumin is used as a model protein drug.The scaffolds display a homogeneous microparticle distribution,and a reduction in pore size and percolation diameter with increased microparticle addition,although these values did not fall below those reported as necessary for cell invasion.The protein distribution within the microparticles,near the surface or more deeply located within the microparticles,was important in determining the release profile and effect of crosslinking,as the surface was affected by the carbodiimide crosslinking reaction applied to the scaffold.Crosslinking of microparticles with a high proportion of protein at the surface caused both a reduction and delay in protein release.Protein located within the bulk of the microparticles,was protected from the crosslinking reaction and no delay in the overall release profile was seen.
