Yang Hun Lee

Functionalizing cellulose scaffold prepared by ionic liquid with bovine serum albumin for biomedical application

The present study reports the preparation of a cellulose scaffold for tissue engineering directly from cellulose fiber using ionic liquid (IL) by the NaCl leaching method with bovine serum albumin (BSA), which is well known protein utilized for biomedical applications like degradation of polymer, cell attachment and proliferation on scaffold. The 1-n-allyl-3-methylimidazolium chloride (AmimCl) IL was used as a solvent for cellulose. The morphology of the scaffold was studied by scanning electron microscopy (SEM) and the images showed that the pore sizes of the scaffolds were about 200 µm. In addition, the water uptake (WU) and degree of degradation of the cellulose scaffold were measured. Meanwhile, the biocompatibility and bioactivity of the scaffold were determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide (MTT) assay and the Live/Dead viability test. The various results demonstrated the ability of the Mesenchymal stem cells (MSC) to attach to the surface of the scaffolds amplified as percentage of BSA increased in cellulose scaffold.

Effect of Vibration on Drawing and Annealing of High- Speed Spun Poly(trimethylene terephthalate) Fiber

Abstract The physical properties of poly(trimethylene terephthalate) (PTT) fibres were improved by means of vibration in the hot-drawing and annealing, which may be caused by the developed molecular packing. For high-speed spun PTT fibers, it was not until at the take-up speed of 3~4 km/min that the orientation induced crystallization started to emerge due to extensional stress occurred in spin line; confirmed from the results of WAXD and DSC. The PTT fibers obtained at the take-up speeds of 2~3 km/min and then drawn and annealed with vibration possessed low density and weight-crystallinity, but their birefringence was especially high. Moreover, the estimation of both refractive index parallel and normal directions to fiber axis using the interference microscopy showed that the refractive index parallel to the fiber axis was very high, which enhanced the mechanical properties of PTT fiber. Accordingly, the well-oriented chains along the fiber axis allow the PTT fiber to have better physical property such as elastic recovery although the PTT fiber has low density and crystallinity compared to PET and PBT. In effect, the PTT fiber possesses lower birefringence of over 10 times than those of PET and PBT due to its chain conformational characteristics. Therefore, we do suggest that the structural assessment against the subsequent mechanical properties according to various processes in the PTT fiber is preferred to be estimated through the respective refractive indices of parallel and normal to the fiber axis rather than conventional methods such as birefringence, crystallinity, and crystalline orientation.