Preparation And Study Of Silk/Polyurethane Filament As Drug Release System

Silk protein material has striking good physical and chemical properties andbiocompatibility for biomedical and biotechnology uses. Silk fibroin material is alwaysobtained by regeneration in order to adapt appropriate applications. The purpose of this articleis to resolve the problem that the regeneration silk fibroin material is hard, brittle and hassmall toughness, meanwhile to increase the loading drug and control the release of drugaccurately. In this paper, self-prepared natural silk-fibroin powder and medical polyurethanemixed filament was prepared by wet-spinning, the rheological properties of NSFP/BPUspinning solution were studied. The influences of NSFP content and spinning technologyconditions on NSFP/BPU filament were studied by Scanning Electron Microscopy (SEM),Infrared Spectroscopy (FTIR), Dynamic Thermodynamic Analysis (DMA), mechanicaltesting and water absorption test. Using NSFP/BPU filament as drug loading carrier, wedropped the filament in drug solution for drug loading through swelling, and carried out vitrorelease, then analyzed the influences of NSFP content and spinning technology conditions onloading and release properties by ultraviolet and visible spectrophotometer.The rheological properties of NSFP/BPU filament show that with the increasing of shearrate, shear stress increase and viscosity decreases, which is a typical shear thinningphenomenon, namely the pseudo plastic fluid flow characteristics. And with the increase ofNSFP content and coagulating bath temperature, rheological curve drops down, shear stressreduces and viscosity decreases, fluidity increases.NSFP/BPU filament SEM images show that with the increase of NSFP content, surfaceand cross section of filament become rough; holes and NSFP appear on cross section,especially when the NSFP content is 30%, the holes increase and the pore size increases. Atthe same time, NSFP is uniformly distributed without apparent agglomerations, whichimplied that NSFP has good compatibility with BPU. FTIR results show that in the infraredspectra of the different content of filaments, BPU absorption peaks have no change withdifferent NSFP content, that is to say, there is no new absorption peak and disappearingabsorption peak. This indicates that no new functional groups and chemical iterations form between BPU and NSFP. DMA diagram shows that with the increase of NSFP content andcoagulating bath temperature, the storage modulus decreased, that is to say, the stiffness offilament decreased.. In addition, the NSFP reduces the mechanical properties of the filament,but enhances the water absorption of the filament.We used NSFP/BPU filament as drug loading carrier, and carried out vitro release. Drugloading and release properties of filament are closely related to the structure and properties ofthe filament. When there are more NSFP content, winding speed is small, temperature ofcoagulation bath is low, the properties of drug loading and release are better. Moreover, thevitro release rate results show that NSFP/BPU filament has certain effect on controlling drugrelease.