Multilayer enzyme electrode membrane
First Claim
1. A method of making a contiguous multilayer membrane of about 40 to about 100 microns in overall thickness suitable for use with an electrochemical sensor in the measurement of an unknown which comprises:
- providing as a first layer, a polymer dissolved in an inert organic solvent and casting said polymer in solution onto an inert support surface which is unreactive with said polymer and does not form a bond to said polymer;
permitting said solution to form a film and thereby obtaining a first relatively nonporous dense polymer layer of about 2 to about 5 microns in thickness;
providing as a second layer, a composition comprising a polymer dissolved in an inert organic solvent, mixing said polymer dissolved in solvent with a nonsolvent for said polymer to obtain a dispersion and thereafter casting said dispersion onto said first layer and thereafter permitting said second layer to dry to form a porous polymer layer of about 2 to about 20 microns in thickness and less dense and more porous than the first layer;
providing a third layer comprising an enzyme solution or suspension and depositing said third layer onto the exposed surface of the second layer;
providing as a fourth layer, a composition comprising a polymer dissolved in an inert organic solvent, mixing said polymer dissolved in solvent with a nonsolvent for said polymer to obtain a dispersion and thereafter casing said dispersion onto the exposed surface of the third layer to provide a fourth porous polymer layer of about 2 to about 20 microns in thickness and less dense and more porous than the first layer; and
thereby forming said contiguous multilayer membrane.
1 Assignment
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Accused Products
Abstract
A contiguous multilayer membrane for use with an electrochemical sensor is prepared comprising a first relatively nonporous dense polymer layer, a second polymer layer less dense and more porous than the first layer, a third layer containing an enzyme and a fourth polymer layer less dense and more porous than the first layer. The polymer is preferably cellulose acetate and the second and fourth layers are prepared with a solvent and nonsolvent for the polymer. The membrane may contain multiple enzyme layers separated by a polymer layer. The multilayer membrane provides advantages of higher substrate conversion, homogeneous distribution of enzyme and/or minimized interference with analyte diffusion.
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Citations
15 Claims
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1. A method of making a contiguous multilayer membrane of about 40 to about 100 microns in overall thickness suitable for use with an electrochemical sensor in the measurement of an unknown which comprises:
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providing as a first layer, a polymer dissolved in an inert organic solvent and casting said polymer in solution onto an inert support surface which is unreactive with said polymer and does not form a bond to said polymer; permitting said solution to form a film and thereby obtaining a first relatively nonporous dense polymer layer of about 2 to about 5 microns in thickness; providing as a second layer, a composition comprising a polymer dissolved in an inert organic solvent, mixing said polymer dissolved in solvent with a nonsolvent for said polymer to obtain a dispersion and thereafter casting said dispersion onto said first layer and thereafter permitting said second layer to dry to form a porous polymer layer of about 2 to about 20 microns in thickness and less dense and more porous than the first layer; providing a third layer comprising an enzyme solution or suspension and depositing said third layer onto the exposed surface of the second layer; providing as a fourth layer, a composition comprising a polymer dissolved in an inert organic solvent, mixing said polymer dissolved in solvent with a nonsolvent for said polymer to obtain a dispersion and thereafter casing said dispersion onto the exposed surface of the third layer to provide a fourth porous polymer layer of about 2 to about 20 microns in thickness and less dense and more porous than the first layer; and thereby forming said contiguous multilayer membrane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 14, 15)
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9. A method of making a contiguous multilayer membrane of about 40 to about 100 microns in overall thickness suitable for use with an electrochemical sensor in the measurement of an unknown which comprises:
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(a) providing a first cellulose acetate polymer dissolved in an inert organic solvent; (b) casting said first polymer in solution onto an inert support surface which in unreactive with said cellulose acetate and does not form a bond to said cellulose acetate; (c) permitting said first polymer in solution to form a film and thereby obtain a first relatively nonporous dense layer of cellulose acetate of about 2 to about 5 microns in thickness; (d) providing a second cellulose acetate polymer dissolved in an inert organic solvent mixing said second polymer with a nonsolvent for said polymer to form a dispersion thereof; (e) casting said second cellulose acetate polymer dispersion onto said first layer of cellulose acetate and permitting said cellulose acetate polymer to form a porous second cellulose acetate layer of about 2 to about 20 microns in thickness and less dense and more porous than the first layer; (f) providing an aqueous solution or suspension of an enzyme and depositing said enzyme in a layer onto the surface of said second polymer; and (g) repeating (d), (e) and (f) at least once to deposit at least one additional said second cellulose acetate layer and at least one additional enzyme layer; thereby forming said contiguous multilayer cellulose acetate polymer membrane. - View Dependent Claims (10, 11, 12, 13)
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Specification