Two-dimensional diffusion glucose substrate sensing electrode

Claim 1

A sensor system for determining the concentration of a predetermined first material in a body fluid, which first material reacts stoichiometrically in said body fluid in the presence of a catalyst or enzyme with a second material to form a third material, which system comprises: first sensor means and second sensor means, each having a surface sensitive to either said second material or said third material and each producing a signal indicative of the concentration of said second or third material in said body fluid in contact with said surface of said sensor means; a first permeable layer disposed completely across the surface of said first sensor means and containing said catalyst or enzyme, said first layer being permeable to all of said first, second and third materials; a like first permeable layer disposed completely across the surface of said second sensor means but not containing said catalyst or enzyme; a second permeable layer disposed completely across each of said first layers distal to said surface of said sensor means, said second layer being permeable to said second material but substantially impermeable to said first material; the disposition of said first and second layers thus permitting said second material to enter said layers for migration to said sensor means through the periphery of both of said layers and the distal surface of said second layer but essentially permitting like entry of said first material only through the periphery of said first layer; and means to compare said signals to determine the concentration of said first material in said body fluid.

Claim 11

A method for determining the concentration of a predetermined first material in a body fluid, which comprises: (a) placing in said body fluid a sensor system comprising first and second sensor means, each having a surface sensitive to either a second or third material in said body fluid, a first permeable layer disposed completely across the surface of both said sensor means and a second permeable layer disposed completely across said first permeable layer distal to said sensor means surface, said first layer being permeable to all of said first, second and third materials and said second layer being permeable to said second material and substantially impermeable to said first material, with said first layer disposed across the surface of said first sensor means having contained therein a catalyst or enzyme in whose presence said first material will react stoichiometrically with said second material to form said third material; (b) passing a quantity of said body fluid through the periphery of said layers and the surface of said second layer distal to said sensor means, that portion of said fluid passing through the periphery of said first layer containing both said first and second materials and the remaining portion of said quantity of body fluid containing only said second material; (c) for that portion of said body fluid passing through said first layer to said surface of said second sensor means, generating from said second sensor means a first signal indicative of the concentration of said second or third material in said body fluid; (d) in that portion of said body fluid passing through said first layer to said first sensor means, stoichiometrically reacting said first and second materials in the presence of said catalyst or enzyme to form said third material, conveying unreacted second material and said third material to said surface of said first sensor means, and from said first sensor means generating a second signal indicative of the concentration of said second or third material in said body fluid following said reaction; and (e) comparing said signals to determine the concentration of said first material in said body fluid.

Claim 12

A method for determining the concentration of a predetermined first material in a body fluid, which comprises: (a) placing in said body fluid a sensor system comprising first and second sensor means, each having a surface sensitive to either a second or third material in said body fluid, a first permeable layer disposed completely across the surface of both said sensor means and a second permeable layer disposed completely across said first permeable layer distal to said sensor means surface, said first layer being permeable to all of said first, second and third materials and said second layer being permeable to said second material and substantially impermeable to said first material, with said first layer disposed across the surface of said first sensor means having contained therein a catalyst or enzyme in whose presence said first material will react stoichiometrically with said second material to form said third material; (b) passing a quantity of said body fluid through the periphery of said layers and the surface of said second layer distal to said sensor means, that portion of said fluid passing through the periphery of said first layer containing both said first and second materials and the remaining portion of said quantity of body fluid containing only said second material; (c) for that portion of said body fluid passing through said first layer to said surface of said second sensor means, generating from said second sensor means a first signal indicative of the concentration of said second or third material in said body fluid; (d) in that portion of said body fluid passing through said first layer to said first sensor means, stoichiometrically reacting said first and second materials in the presence of said catalyst or enzyme to form said third material, conveying unreacted second material and said third material to said surface of said first sensor means, and from said first sensor means generating a second signal indicative of the concentration of said second or third material in said body fluid following said reaction; and (e) comparing said signals to determine the concentration of said first material in said body fluid.