loading page

Immobilisation and characterisation of urease in mechanically robust silk fibroin membrane based on unidirectional nanopore dehydration
  • Meng Zhang,
  • Hai-yan Wang,
  • Yu-Qing Zhang
Meng Zhang
Soochow University
Author Profile
Hai-yan Wang
The People's Hospital of Suzhou New District
Author Profile
Yu-Qing Zhang
Soochow University

Corresponding Author:[email protected]

Author Profile

Abstract

Silk fibroin (SF) is a good carrier for immobilised enzymes and drugs. In this experiment, unidirectional nanopore dehydration (UND) was used to dehydrate a regenerated SF solution containing urease in one step to prepare a urease-immobilised SF membrane (UI-SFM). UI-SFM has high mechanical strength and a secondary structure dominated by the Silk I structure. The results indicated that the immobilization of urease in UI-SFM exhibited superior enzyme recovery and stability. In order to further improve the activity recovery rate and stability of the UI-SFM, a more stable immobilised urease membrane (UI-SFMs) was obtained by stretching the above UI-SFM; another urease-immobilised cross-linked SFM (UI-SFMc) was also obtained by adding a cross-linking agent−polyethylene glycol diglycidyl ether (PEGDE) before UND. The thermal and storage stability of the two enzyme membranes were significantly improved, and their enzyme activity recovery rates reached more than 90%. After the enzymatic reactions were repeated ten times, the activity recovery rates of the two UI-SFMs and UI-SFMc were maintained at 92% and 88%. These results indicate that PEGDE addition prior to UND or post-stretching treatment for UI-SFM can make the immobilised urease activity in the SFM more stable, which opens up new applications of UND technology in urease immobilisation.