# US 11,998,330 B2 · Interference rejection membranes useful with analyte sensors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,998,330 B2 - Document ID: US11998330B2 - Status: Granted - Kind: B2 - Application number: 17/162,885 - Filed: 2021-01-29 - Published: 2022-08-04 - Granted: 2024-06-04 - Earliest claimed: 2021-01-29 - Assignees: Medtronic MiniMed, Inc. - Applicants: Medtronic MiniMed, Inc. - Inventors: Ashwin K. Rao; Qingling Yang; Ellis Garai; Daniel E. Pesantez - Web page: https://patentgrep.com/patent/US11998330B2 ## CPC - A61B 5/14865: {invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors} - A61B 5/14532: {for measuring glucose, e.g. by tissue impedance measurement} - A61B 5/1486: using enzyme electrodes, e.g. with immobilised oxidase - A61B 5/7246: {using correlation, e.g. template matching or determination of similarity} - A61B 2562/125: characterised by the manufacture of electrodes - G01N 27/3272: {Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels (optical biosensors G01N33/52)} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Embodiments of the invention provide amperometric analyte sensors having optimized elements such as interference rejection membranes, and associated architectures, as well as methods for making and using such sensors. While embodiments of the innovation can be used in a variety of contexts, typical embodiments of the invention include glucose sensors used in the management of diabetes. ## Claims ### Claim 1 A method of making an amperometric analyte sensor for implantation within a mammal comprising the steps of: providing a first base layer; forming a conductive layer on the first base layer, wherein the conductive layer includes a first working electrode; forming an analyte sensing layer on the conductive layer, wherein the analyte sensing layer includes an enzyme selected to generate a detectable electrical signal upon exposure to an analyte, wherein: the analyte sensing layer is formed by combining a polymerizable monomer, a crosslinking agent and a photoinitiator agent; forming an interference rejection layer on the analyte sensing layer, wherein: the interference rejection layer is formed by a reaction mixture comprising a polymerizable monomer, a crosslinking agent and a photoinitiator agent; the reaction mixture comprises a 15% to 96% of crosslinker to monomer ratio; and the analyte sensing layer and the interference rejection layer are formed when the reaction mixture is polymerized by exposure to light; and forming an analyte modulating layer on the interference rejection layer; such that an amperometric analyte sensor for implantation within a mammal is made. ### Claim 2 (depends on 1) The method of claim 1, wherein: (a) the reaction mixture forms a polyvinyl alcohol polymer or a poly(2-hydroxyethyl methacrylate) polymer; (b) polymerizable monomer comprises a hydroxyethylmethacrylate monomer, a methyl methacrylate monomer and/or a hydroxybutyl methacrylate monomer; (c) the crosslinking agent comprises an ethylene glycol and/or a silane; and/or (d) relative amounts of crosslinking agent and polymerizable monomer disposed within the reaction mixture are selected such that the reaction mixture comprises 50%-80% crosslinking agent and 20%-50% polymerizable monomer. ### Claim 3 (depends on 2) The method of claim 2, wherein the analyte sensing layer is formed by combining a polymerizable monomer, a crosslinking agent and a photoinitiator agent and the analyte sensing layer is formed when the reaction mixture is polymerized by exposure to light. ### Claim 4 (depends on 1) The method of claim 1, wherein: the reaction mixture comprises a diazo photoreactive crosslinking agent; the reaction mixture comprises an ethylene glycol diacrylate crosslinking agent; and/or the method of claim 1 further comprises forming a layer comprising an ascorbic acid oxidase enzyme. ### Claim 5 (depends on 4) The method of claim 4, wherein: the layer comprising an ascorbic acid oxidase enzyme comprises glucose oxidase or comprises an analyte modulating layer; or the layer comprising an ascorbic acid oxidase enzyme does not comprise glucose oxidase or does not comprise an analyte modulating layer. ### Claim 6 (depends on 1) The method of claim 1, wherein: the conductive layer includes a second working electrode, wherein said second working electrode comprises an analyte sensing layer and an analyte modulating layer and does not comprise an interference rejection layer; and/or the conductive layer includes a background electrode, wherein said background electrode does not comprise an analyte sensing layer, an analyte modulating layer; or an interference rejection layer. ### Claim 7 (depends on 1) The method of claim 1, wherein the interference rejection layer is formed in a single step comprising exposure to light. ### Claim 8 (depends on 1) The method of claim 1, wherein the interference rejection layer is formed in a plurality of steps comprising exposure to light. ### Claim 9 (depends on 8) The method of claim 8, wherein the plurality of steps comprising exposure to light comprises: a first exposure to light selected to partially polymerize the interference rejection reaction mixture comprising a polymerizable monomer, a crosslinking agent and a photoinitiator agent; and a second exposure to light selected to fully polymerize: the reaction mixture comprising a polymerizable monomer, a crosslinking agent and a photoinitiator agent; and the partially polymerized interference rejection reaction mixture. ### Claim 10 (depends on 7) The method of claim 7, wherein at least one interference rejection reaction mixture is selectively disposed on a location on the first base layer and/or one photomask is used to selectively polymerize an interference rejection reaction mixture disposed on the first base layer such that contact pads and/or conductor traces disposed on the first base layer do not comprise an interference rejection layer.