Novel membranes prepared from collagen fibrils using LiOH/urea aqueous system crosslinked by tannic acid

In this work, a rapid and controlled exfoliation of collagen fibrils from bovine tendons in LiOH/urea aqueous system combined with freeze-thaw cycles was developed to preserve the native structure of collagen. The prepared collagen fibril membranes by vacuum filtration approach exhibited excellent transparency and mechanical properties. Particularly, the optimal tensile strength can reach 144.2 and 1.51 MPa in the dry and wet states, respectively, which is significantly superior to traditional acid-soluble collagen membrane. The fibril membranes also showed good resistance in acids, alkalis and organic solvents, as well as thermal stability. Moreover, the use of tannic acid as a bio-crosslinking agent further improved their mechanical performances. This work provides a new avenue for the preparation of collagen-based materials with native mesostructures.