Liu Shiwei

Stability and activity of cellulase modified with polyethylene glycol (PEG) at different amino groups in the ionic liquid [C2OHmim][OAc]

ABSTRACT Polyethylene glycol (PEG), as a suitable tool to improve enzyme stability, such as monomethoxyl-polyethylene glycol aldehyde (mPEG-ALD) and monomethoxyl-polyethylene glycol succinimide (mPEG-SPA), has been appended at the ε-amino group of lysine or the N-terminal α-amino acid residue of commercial cellulase. The modified cellulases thus obtained are designated as Cell-ALD and Cell-SPA, respectively. The stabilities and activities of these modified cellulases have been studied in the ionic liquid [C2OHmim][OAc]. Cell-ALD showed excellent stability and activity in [C2OHmim][OAc], such as the activity of Cell-ALD 5k (molecular weight of ALD is 5000), which can reach above 80% of its original value after remaining in [C2OHmim][OAc] for 24 h, and outstanding performance in the hydrolysis of natural cellulose.

Alkyl chitosan film‐high strength, functional biomaterials

Biofilm with strong tensile strength is a topic item in the area of tissue engineering, medicine engineering, and so forth. Here we introduced an alkyl chitosan film with strong tensile strength and its possibility for an absorbable anticoagulation material in vivo was tested in the series of blood test, such as dynamic coagulation time, plasma recalcification time and hemolysis. Alkyl chitosan film was a better biomaterial than traditional chitosan film in the anticoagulation, tissue compatibility and cell compatibility. The unique trait of alkyl chitosan film may be for its greater contact angle and hydrophobicity ability to reduce the adsorption capacity for the blood component and the activity of fibrinolytic enzymes, enhance the antibacterial capacity than chitosan film. Moreover, none of chitosan film or butyl chitosan film exhibited quick inflammation or other disadvantage and degraded quickly by implanted test. Therefore, Alkyl chitosan film is of prospective properties as an implantable, absorbable agent for tissue heals, and this material need further research.