RESUMEN
The property of biomaterials to control the sequential release of growth factors has been widely concerned in the field of bone repair and regeneration. Double-factor sustained-release scaffolds have good biocompatibility and bioactivity. OCarboxymethyl chitosan microspheres (O-CMCS) has antimicrobial activity, biodegradability, biocompatibility and film formation. This study developed scaffolds materials with microspheres with a purpose of forming a controlled slow release secondary structure. O-CMCS were used as drug carrier to construct the compound sustained-release system with rhBMP-2 and VEGF double factors release. The O-CMCS were loaded with rhBMP-2 and the hydroxyapatite collagen (HC) scaffolds were loaded with VEGF to prepare the scaffolds. These were double factors composite sustained-release system scaffolds. The biocompatibility of the sustained-release system was evaluated by in vitro and in vivo experiments. HC composite scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction detection (XRD), in vitro sustained release test, in vitro cell culture and in vivo animal experiments. The results showed that rhBMP-2/VEGF in HC composite scaffolds (HCBV) successfully achieved the sequential release of the double factors, which could benefit bone regeneration.
Asunto(s)
Materiales Biocompatibles/química , Proteína Morfogenética Ósea 2/administración & dosificación , Regeneración Ósea/efectos de los fármacos , Ingeniería de Tejidos , Factor de Crecimiento Transformador beta/administración & dosificación , Factor A de Crecimiento Endotelial Vascular/administración & dosificación , Animales , Materiales Biocompatibles/administración & dosificación , Materiales Biocompatibles/síntesis química , Proteína Morfogenética Ósea 2/química , Proteína Morfogenética Ósea 2/genética , Regeneración Ósea/genética , Huesos/efectos de los fármacos , Quitosano/análogos & derivados , Quitosano/química , Colágeno/administración & dosificación , Colágeno/química , Liberación de Fármacos/efectos de los fármacos , Durapatita/síntesis química , Durapatita/química , Humanos , Microscopía Electrónica de Rastreo , Microesferas , Osteogénesis/efectos de los fármacos , Ratas , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Espectroscopía Infrarroja por Transformada de Fourier , Andamios del Tejido/química , Factor de Crecimiento Transformador beta/química , Factor de Crecimiento Transformador beta/genética , Factor A de Crecimiento Endotelial Vascular/química , Factor A de Crecimiento Endotelial Vascular/genéticaRESUMEN
Owing to low bearing capacity and efficiency, traditional filters or adsorbents for removal of contaminants like crystal violet (CV) dye required frequent replacement. Besides, the combination of three-dimensional (3D) printing and bionics could break the constraints of traditional configuration. In this study, a novel depth-type hybrid polylactic acid (PLA)@graphene oxide (GO)/chitosan (CS) sponge filter with bionic fish-mouth structure was prepared and fabricated, assisted by 3D printing and double freeze-drying technology, according to the theories of vertical cross-step filtration and swirling flow. And GO/CS sponge and its filtering device were characterized by FITR, SEM, water adsorption and so on. Moreover, it was explained that the impact factors on dye removal mechanism, like GO content (or CS content), contact time, pH, temperature and bionic configuration. As a result, the bionic 3D filtering device demonstrated excellent removal efficiency (97.8±0.5% for CV) and GO/CS sponge exhibited higher strength (74.5±3.5MPa) at the condition of GO content of 9wt%, contact time of 46min, pH of 8 and 35°C, respectively. Therefore, the resulting 3D PLA@GO/CS sponge bionic filter via gravity and vortex driving provided new alternatives for effectively dye-water separation, and it showed great promise for application of biological macromolecules in adsorption.
Asunto(s)
Quitosano/química , Violeta de Genciana/química , Violeta de Genciana/aislamiento & purificación , Grafito/química , Óxidos/química , Poliésteres/química , Adsorción , Colorantes/química , Colorantes/aislamiento & purificación , Filtración , Concentración de Iones de Hidrógeno , Fenómenos Mecánicos , Modelos Moleculares , Conformación Molecular , Porosidad , Temperatura , Agua/química , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificaciónRESUMEN
Cephalosporin 7 alpha-hydroxylase, which catalyses the conversion of cephalosporins into their 7 alpha-hydroxy derivatives, was purified nearly 390-fold from Streptomyces clavuligerus through ion-exchange chromatography, (NH4)2SO4 fractionation, gel filtration and dye chromatography, with the use of h.p.l.c. to monitor enzyme activity. The nearly pure enzyme migrates as a single major band, with an Mr of 32,000 in SDS/PAGE. Its optimum pH is in the range 7.3-7.7. Under our conditions the reaction was fastest at temperatures in the range 20-30 degrees C. The Km for cephalosporin C is 0.72 mM, and the Vmax. is 15.4 mumol of cephalosporin C hydroxylated/min per mg. Cephalosporin 7 alpha-hydroxylase did not show any deacetoxycephalosporin C synthase or deacetoxycephalosporin C hydroxylase activity.
Asunto(s)
Transferasas Intramoleculares , Oxigenasas de Función Mixta/aislamiento & purificación , Proteínas de Unión a las Penicilinas , Streptomyces/enzimología , Cefalosporinas/metabolismo , Cromatografía de Afinidad , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Isomerasas/metabolismo , Cinética , Oxigenasas de Función Mixta/metabolismo , Oxigenasas/metabolismo , TemperaturaRESUMEN
This study reports the phenotype frequencies (PF) and gene frequencies (GF) of a homogeneous Sichuan Han Chinese population by typing of unrelated 229 individuals and 16 families for HLA-A, B, C, DR and DQ antigens. The frequencies of Bw67, Bw71, DRw12, DRw13 and DRw14 are the first to be reported in Chinese. Two two-locus haplotypes with significant linkage disequilibrium among the Sichuan have also been listed.