Abstract: A flexible porous free-standing protein membrane includes cross-linked protein. At least part of pores of the porous membrane is formed by removing nanostrands whose diameters are 2-3 nm, the cross-linked protein is cross-linked by a bifunctional cross-linker, and a thickness of the protein membrane is 10 ?m or less.

Abstract: A fabrication method for a flexible porous free-standing protein membrane formed by cross-linked protein includes (1) mixing nanostructured materials and protein to obtain a composite made of protein and nanostructured materials (for example metal hydroxide nanostrands); (2) forming a membranous body formed by the composite made of protein and nanostructured materials, and mutually cross-linking the protein by a cross-linker; and (3) dissolving and removing the nanostructured materials to produce a flexible porous free-standing protein membrane.

Abstract: A method for fabricating a flexible free-standing ultrathin (nano) or thin protein membrane that includes (1) keeping a dilute metal (Cd, Cu or Zn) nitrate or chloride solution under neutral or weak basic pH to spontaneously form metal (Cd, Cu or Zn) hydroxide nanostrands; (2) mixing the metal (Cd, Cu or Zn) hydroxide nanostrands and protein solution to obtain composite nanofibers made of protein and the metal (Cd, Cu or Zn) hydroxide nanostrands; (3) filtering the obtained dispersion of composite nanofibers on a filter; (4) cross-linking the proteins contained in the composite nanofibers by a bifunctional cross-linker; and (5) removing the metal (Cd, Cu or Zn) hydroxide nanostrands.

Abstract: [Purpose] A purpose of this invention is to provide a robust and flexible free-standing ultrathin (nano) or thin pure protein membrane which enables a rapid and simple separation (or condensation) of relatively small (M.W.=ca. 1,000 Da) molecules. [Summary] A flexible free-standing ultrathin (nano) or thin protein membrane can be fabricated by a method comprising following steps: (1) A dilute metal (Cd, Cu or Zn) nitrate or chloride solution is kept under neutral or weak basic pH to spontaneously form metal (Cd, Cu or Zn) hydroxide nanostrands; (2) The above metal (Cd, Cu or Zn) hydroxide nanostrands and protein solution are mixed to obtain composite nanofibers made of protein and the said metal hydroxide nanostrands; (3) The obtained dispersion of composite nanofibers is filtered on a filter. (4) Proteins contained in the composite nanofibers are cross-linked by bifunctional cross-linkers; and (5) Metal (Cd, Cu or Zn) hydroxide nanostrands are removed from them.

Abstract: [Purpose] A purpose of this invention is to provide a robust and flexible free-standing ultrathin (nano) or thin pure protein membrane which enables a rapid and simple separation (or condensation) of relatively small (M.W.=ca. 1,000 Da) molecules. [Summary] A porous free-standing protein membrane formed by cross-liked protein of this invention can be fabricated by a method comprising following steps: (1) a first step of mixing nanostructured materials and protein to obtain composite made of protein and nanostructured materials (for example metal hydroxide nanostrands); (2) a second step of forming a membranous body formed by said composite made of protein and nanostructured materials, and mutually cross-linking said protein by means of a cross-linker; and (3) a third step of dissolving and removing said nanostructured materials to produce a porous membrane.