Research On Electrospinning Technology For Enzyme Immobilization

Enzyme immobilization is to find a suitable carrier of enzyme for promoted stability and utilization during catalytic reaction.Many strategies have been explored for enzyme immobilization,one of which is electrospinning technique.Fiber membrane made from electrospinning has high poriness,large specific surface area,thus becoming a highly desirable carrier for enzyme.However,the process of enzyme immobilization usually compromise the activity of enzyme.It has been reported that enzyme grafted with ?-CD has a promoted activity and there is a guest-host interaction between adamantane and ?-CD.Inspired by these appealing properties of P-CD,in this article,we designed and exploited immobilization of enzyme on fiber membrane made of enzyme grafted with ?-CD and chitosan grafted with adamantane through electrospinning technique.The strength of carrier and activity of enzyme could be enhanced due to the guest-host interaction between these two components.EDC and NHS were used to activate adamantane acid for grafting to chitosan.Infrared spectroscopy and NMR showed the grafting ratio of adamantane acid was about 1.7%.It was difficult to fabricate fiber membrane only with chitosan grafted with adamantane through electrospinning.Thus,chitosan grafted with adamantane,polyvinyl alcohol(PVA)and polyethylene oxide(PEO)were blended for electrospinning.The parameters of electrospinning were optimized and the optimal result was as following:the mass ratio of chitosan grafted with adamantane,PVA and EPO was 5:4:1;the voltage of electrospinning was 18kV;the injection speed was 0.2 mm/min;the receiving distance was 21cm.The fibers fabricated under this condition were homogeneous and the diameter of fibers was about 370nm.Water contact angle indicated fabricated fiber membrane had good hydrophilicity.Furthermore,?-CD after activated with EDC and NHS was used for grafting to xylanase,horse radish peroxidase(HRP)and glucose oxidase(GOX),and then those enzymes were immobilized with optimal electrospinning parameters that we mentioned above.Laser confocal microscopy showed enzymes labeled with FITC uniformly distributed in fibers.We then explored the activity of different enzymes,it showed that compared with resolvase,enzymes grafted with P-CD had a promoted catalytic activity and the enhanced ratio were about 35%,15%and 7%for xylanase,HRP and GOX respectively.The stability of enzymes were also enhanced after immobilization.After repeatedly catalytic reaction of 7 to 8 times,the immobilized enzymes could still remain activity of 50%.In conclusion,according to the guest-host interaction between adamantane and ?-CD,we fabricated fiber membranes made of enzyme grafted with ?-CD and chitosan grafted with adamantane,thus achieving immobilization of various enzymes with promoted activity and stability through electrospinning technique.This strategy of enzyme immobilization is facile and universal,which has a promising application in production.