VPA/PLGA microfibers produced by coaxial electrospinning for the treatment of central nervous system injury

The central nervous system shows limited regenerative capacity after injury. Spinal cord injury (SCI) is a devastating traumatic injury resulting in loss of sensory, motor, and autonomic function distal from the level of injury. An appropriate combination of biomaterials and bioactive substances is currently thought to be a promising approach to treat this condition. Systemic administration of valproic acid (VPA) has been previously shown to promote functional recovery in animal models of SCI. In this study, VPA was encapsulated in poly(lactic-co-glycolic acid) (PLGA) microfibers by the coaxial electrospinning technique. Fibers showed continuous and cylindrical morphology, randomly oriented fibers, and compatible morphological and mechanical characteristics for application in SCI. Drug-release analysis indicated a rapid release of VPA during the first day of the in vitro test. The coaxial fibers containing VPA supported adhesion, viability, and proliferation of PC12 cells. In addition, the VPA/PLGA microfibers induced the reduction of PC12 cell viability, as has already been described in the literature. The biomaterials were implanted in rats after SCI. The groups that received the implants did not show increased functional recovery or tissue regeneration compared to the control. These results indicated the cytocompatibility of the VPA/PLGA core-shell microfibers and that it may be a promising approach to treat SCI when combined with other strategies.

Research on Thin Film type Hydrogen Sulfide Sensor Based on SnO2-CuO Nanofibers / 分析化学

A SnO2-CuO composite nanofiber was prepared by the coaxial electrospinning method. A new thin-film-type hydrogen sulfide gas sensor was designed by coating SnO2-CuO composite nanofibers onto an alumina ceramic tube with Au electrodes by dip-coating method. The crystalline phase and microstructure of SnO2-CuO composite nanofibers were characterized using X-ray diffraction ( XRD ) and scanning electron microscope ( SEM) . The influence of chemical composition and thickness of sensitive film on the sensitive mechanism and electrochemical characteristic of SnO2-CuO nanofibers were analyzed. The characteristic tests of hydrogen sulfide sensor including sensitive performance, temperature, relative humidity, dynamic response, interference and stability were carried out by WS-30A type multifunction analyzer in gas sensor test system. The results demonstrated that, when the operating temperature was 25℃ and hydrogen sulfide gas concentration increased from 10 to 60 mg/L, the hydrogen sulfide sensor based on C50 composite nanofibers with 70 nm sensitive film thickness had the best linearity (92. 3%) and sensitivity (98. 2%). Besides, its highest response values and relatively humidity level were 1080 and 95%, respectively, and its dynamic response time and recover time were 4 s and 12 s, respectively. This sensor showed good anti-disturbance to the gases, such as CO, NO2 , SO2 , NH3 , CO2 , CH4 and H2 . The response value of the sensor was attenuated about 9. 2% when it was applied continually in the mine about 12 months, and its normal response time was 10. 9 months.

Preparation of sustained release ethyl cellulose nanofibers by coaxial electrospinning with ethanol as sheath fluid / 中国药学杂志

OBJECTIVE: To investigate the preparation of sustained release drug-loaded nanofibers by using a modified coaxial electrospinning process, in which only solvent is exploited as sheath fluid. METHODS: Ethanol was used as sheath fluid and ethyl cellulose (EC) and ferulic acid (FA) were taken as filament-forming matrix and active pharmaceutical ingredient, respectively. RESULTS: Drug-loaded EC nanofibers were smoothly and continuously generated without any clogging through the coaxial process. Field-emission scanning electron microscopic observations demonstrated that the nanofibers' diameters could be manipulated through adjusting the flow rate of sheath fluid. The composite nanofibers were in essential a molecular solid dispersion of EC and FA based on the hydrogen bonding between them, as verified by XRD and FTIR results. In vitro dissolution tests showed that FA in the nanofibers had a fine sustained release profile via a typical Fickian diffusion mechanism. CONCLUSION: The modified coaxial electrospinning with solvent as sheath fluid can be a useful tool for developing novel sustained release drug delivery systems.