Microporous membrane substrate having caustic stable, low protein binding surface
AssigneeMillipore Corporation
InventorJohn Charkoudian
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Abstract
The present invention provides porous media or membranes having a surface coating that includes a first coating of a cross-linked terpolymer and a second coating comprising a copolymer or a terpolymer modified with a hydrophilic or hydrophobic functional group which has a superior combination of properties, including heat stable biomolecule resistant adsorptive properties, resistance to strong alkaline solutions, and low levels of extractable matter.
Claims39
A clean porous membrane comprising a porous substrate and a separately formed heat stable biomolecule resistant surface having a biomolecule binding of less than about 30 micrograms per square centimeter as measured by the IgG binding test.
A clean, caustic resistant, porous membrane comprising a microporous membrane substrate and a heat stable biomolecule resistant surface, wherein said heat stable biomolecule resistant surface is a separately formed surface coating which comprises:
- a first coating comprising a first crosslinked terpolymer, said terpolymer comprising at least two monofunctional monomers selected from the group consisting of acrylamides, methacrylamides, and N-vinyl pyrrolidones, and at least one polyfunctional monomer selected from the group consisting of polyfunctional acrylamides, polyfunctional methacrylamides, and diacroylpiperazines and a second coating comprising a second crosslinked terpolymer, or copolymer modified with functional groups selected from the group consisting of hydrophilic functional groups and hydrophobic functional groups.
A clean, caustic resistant, porous membrane comprising a polyvinylidene difluoride microporous membrane substrate and a heat stable biomolecule resistant surface, wherein said first coating is a separately formed surface coating which comprises a first crosslinked terpolymer, said crosslinked terpolymer of said first coating being a copolymer formed from either:
- (a) methylene-bis-acrylamide, dimethylacrylamide, and diacetone acrylamide;
- or
- (b) methylene-bis-acrylamide, N-vinyl pyrrolidone, and either of dimethylacrylamide or diacetone acrylamide,
- and a second coating comprising a second crosslinked terpolymer or copolymer modified with functional groups selected from the group consisting of hydrophilic functional groups and hydrophobic groups.
A method for the preparation of a clean, caustic resistant porous membrane, said membrane comprising a porous membrane substrate and a heat stable biomolecule resistant surface coating, said method comprising the steps of:
- a. providing a porous membrane substrate;
- b. optionally washing said porous membrane substrate with a wetting liquid to wet the surfaces thereof;
- c. optionally washing said wet porous membrane substrate with a second wetting liquid to replace said first wetting liquid, leaving said porous membrane substrate wetted with said second liquid;
- d. contacting the surface of said porous membrane substrate with a reactant solution containing:
- (1) at least two monofunctional monomers selected from the group consisting of acrylamides, methacrylamides, and N-vinyl pyrrolidones;
- and
- (2) at least one polyfunctional monomer selected from the group consisting of polyfunctional acrylamides, polyfunctional methacrylamides and diacroylpiperazines;
- said solution optionally further comprising one or more polymerization initiators;
- e. removing the membrane substrate from the solution,
- f. polymerizing said monomers to form said heat stable biomolecule resistant surface;
- g. washing said membrane to form the first coating on the porous substrate,
- h. contacting the membrane from step (g) with an aqueous solution of the, at least one, monofunctional monomers having hydrophilic functional groups, a polyfunctional cross-linking agent and a photo initiator;
- i. removing the porous membrane in step (h) from the aqueous solution;
- j. exposing the membrane from step (i) to ultraviolet light
- k. washing the membrane to form the second coating on the porous membrane and
- l. drying the membrane.
A heat stable functional porous membrane comprising a porous substrate and a separately formed heat stable biomolecule resistant first coating, further comprising a heat stable functional second coating appended to said first coating.
A method for the preparation of a clean, caustic resistant porous membrane, said membrane comprising a porous membrane substrate and a heat stable biomolecule resistant surface coating, said method comprising the steps of:
- a. providing a porous membrane substrate;
- b. optionally washing said porous membrane substrate with a wetting liquid to wet the surfaces thereof;
- c. optionally washing said wet porous membrane substrate with a second wetting liquid to replace said first wetting liquid, leaving said porous membrane substrate wetted with said second liquid;
- d. contacting the surface of said porous membrane substrate with a reactant solution containing:
- (1) at least two monofunctional monomers selected from the group consisting of acrylamides, methacrylamides, and N-vinyl pyrrolidones;
- and
- (2) at least one polyfunctional monomer selected from the group consisting of polyfunctional acrylamides, polyfunctional methacrylamides and diacroylpiperazines;
- said solution optionally further comprising one or more polymerization initiators;
- e. removing the membrane substrate from the solution,
- f. polymerizing said monomers to form said heat stable biomolecule resistant surface;
- g. washing said membrane to form the first coating on the porous substrate,
- h. contacting the membrane from step (g) with a nonaqueous solution of the, at least one, monofunctional monomers having hydrophobic functional groups, a polyfunctional cross-linking agent and a photo initiator;
- i. removing the porous membrane in step (h) from the aqueous solution;
- j. exposing the membrane from step (i) to ultraviolet light
- k. washing the membrane to form the second coating on the porous membrane and
- l. drying the membrane.
Dependencies are inferred from the claim text.