Papers by Author: Jian Xin He

Abstract: Differences in secondary structure among Bombyx mori (B. mori) silk and two wild silks of Antheraea yamamai (A. yamamai) and Antheraea pernyi (A. pernyi) were investigated by CP/MAS 13C NMR Spectroscopy. The β-sheet structure was primary in three silk, and B. mori silk had the highest β-sheet structure. Although amino acid compositions are very similar for two wild silk, their secondary structures had significant difference. A. yamamai silk contained more α-helix structure, whereas more β-turn and random coil structures formed in A. pernyi silk. B. mori silk was mainly composed of anti-parallel β-sheet structure, however, the parallel β-sheet structure was advantage in the two wild silks, and A. yamamai silk contained more anti-parallel β-sheet conformation than A. pernyi silk.

Abstract: Tussah silk fibroin (TSF)/hydroxyapatite (HAP) composites were prepared using the co-precipitation method. The results indicate that pure HAP presents needle-like structure with a length of 120-160 nm and a width of 30-40 nm. TSF/HAP composite prepared by adding 8% TSF exhibits a spherical structure, while with the increase of TSF content, the morphology of the composites changed from spherical to short rod, and the length of composite increases from 78 to 146 nm, but the width keep stability. FTIR spectra show the absorption peaks of TSF/HAP composite attributed to the amide and PO43- shift with the addition of TSF, indicating the existence of interaction between HAP and TSF molecules. TSF/HAP composites show a weak crystalline structure, being similar to nano-HAP existed in human bone tissue, thus suggesting that TSF molecules affect the crystallinity of HAP. TG analysis shows that TSF/HAP composite prepared by adding 17.6% TSF contains 11% TSF.

Abstract: Silk fibroin/cellulose acetate blend Nanofibrous membranes were prepared by electro- spinning and their performances were evaluated as a heavy metal ion adsorbent. The electrospun nanofibrous membranes were comprised of randomly oriented ultra-fine fibers of 100-600nm diameters. As a result of field emission electron microscope (FEEM), compared with pure nanofibrous membranes, the anti-felting shrinkage of SF/CA blend nanofibrous membranes with 20% CA content was markedly improved after treatment with 100% ethanol. Metal ion adsorption test was performed with Cu2+ as a model heavy metal ion in a stock solution. The pure SF nanofibrous membranes exhibited high metal ion capacities compared with that pure CA nanofibrous membrane. Especially, the SF/CA blend nanofibrous membranes had an exceptional performance for the adsorption of metal ions, and the maximum milligrams per gram of metal ions adsorbed reached 22.8mg/g for Cu2+. This indicated that SF and CA had synergetic effect.