Nano-whiskers of -chitin were prepared accord-ing to a reported method [11]. Chitin oligosaccharides (GlcNAc)n(n = 2–6) were purchased from Toronto Research Chemicals(Toronto, Canada).
Plasmid pET28a and the Escherichia coli strainsTOP10 and BL21 (DE3) were purchased from Novagen (Madison,WI). DNA polymerase, restriction enzymes, and T4 DNA ligase werepurchased from Takara (Kyoto, Japan). All other chemicals andreagents used were of analytical grade unless otherwise stated.