Affinity membrane for capture of a target biomolecule and formation thereof by site-directed immobilization of a capture biomolecule
Compositions and methods are taught for directing the orientation of an immobilized capture biomolecule on a hydrophobic membrane. The method comprises layering at least one tie layer on a hydrophobic membrane, adding an amine functional layer on top of at least one tie layer; and attaching an alignment biomolecule to the amine functional layer. The alignment biomolecule has the ability to either capture a target biomolecule itself and thus be considered a capture biomolecule, or bind and orient the immobilized capture biomolecule so as to maximize the binding activity of the immobilized capture biomolecule. In one embodiment, a nickel-coordinated amine functional layer binds with a histidine-tagged alignment biomolecule. In another embodiment, an amine functional layer reacts, via tyrosinase catalysis, with a tyrosine residue in an alignment biomolecule.
1. A membrane-containing composition that directs the orientation of an immobilized peptide or protein on a hydrophobic membrane, said composition comprising:
a) at least one said hydrophobic membrane, said at least one said hydrophobic membrane being selected from the group consisting of a thin porous substrate with straight pores, a polycarbonate membrane, and a track etched membrane;
b) at least one tie layer layered on said hydrophobic membrane, said tie layer being selected from the group consisting of polyvinyl acetate and polyvinyl butyral;
c) an amine functional layer layered on top of said at least one tie layer; said amine-functional layer being nickel-coordinated chitosan;
d) a plurality of peptides or proteins comprising a histidine tag, wherein said histidine tag is attached to said nickel of said nickel-coordinated chitosan, and wherein said immobilized peptides or proteins are aligned on said amine functional layer, and wherein said peptides or proteins are capable of binding to antibodies or target biomolecules.
2. A composition comprising a plurality of said membrane-containing compositions of claim 1 , wherein said membrane-containing compositions form a stack, and wherein each membrane-containing composition is positioned on top of and in contact with another membrane-containing composition.
3. The composition according to claim 1 , wherein said tie layer is soluble in a solvent having a polarity ranging between that of a solvent in which the nickel-coordinated chitosan is soluble to that of a solvent in which the polycarbonate layer is soluble.