# US 2014/0155703 A1 · Transdermal device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155703 A1 - Document ID: US20140155703A1 - Status: Published application - Kind: A1 - Application number: 13/698,889 - Filed: 2011-05-19 - Published: 2014-06-05 - Earliest claimed: 2010-05-20 - Assignees: University of Strathclyde - Inventors: Patricia Connolly - Web page: https://patentgrep.com/patent/US20140155703A1 ## CPC - A61B 5/145: Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value {; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue} (non-radiation detecting or locating of foreign bodies in blood A61B5/06) - A61B 5/0531: Measuring skin impedance - A61B 5/0537: Measuring body composition by impedance, e.g. tissue hydration or fat content - A61B 5/14532: {for measuring glucose, e.g. by tissue impedance measurement} - A61B 5/1477: non-invasive - A61B 5/412: {Detecting or monitoring sepsis} - A61B 10/0064: {for taking sweat or sebum samples (measuring sweat production A61B5/4266)} - A61B 2010/008: {Interstitial fluid} - A61B 2560/0412: Low-profile patch shaped housings - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A transdermal device (10) for sensing one or more analytes in a biological fluid, the device (10) comprising a liquid or gel layer (14); a sensor (18) located in the liquid or gel layer (14) for sensing analyte in the gel layer and an outer layer (16) that is adapted to bind with or trap the one or more analytes of interest, wherein the device (10) is arranged so that in use the analyte is continuously drawn out of the liquid or gel (14) and into the outer layer (16) and the analyte concentration as a function of position across the gel/liquid has a defined profile. ## Claims ### Claim 1 A transdermal device for sensing one or more analytes in a biological fluid, the device comprising a liquid or gel layer; a sensor located in the liquid or gel layer for sensing analyte in the liquid or gel layer and an outer layer adapted to bind with or trap the one or more analytes of interest, wherein the device is arranged so that in use the analyte is continuously drawn out of the liquid or gel and into the outer layer and the analyte concentration as a function of position across the gel/liquid has a defined profile. ### Claim 2 (depends on 1) A device as claimed in claim 1 wherein the sensor is operable to sense analyte concentration in the gel layer as a function of time. ### Claim 3 (depends on 1) A device as claimed in claim 1 wherein the defined profile is linear. ### Claim 4 (depends on 1) A device as claimed in claim 1, wherein the binding/trapping agent is distributed over at least over an area corresponding to a measurement area of the gel or liquid layer. ### Claim 5 (depends on 1) A device as claimed in claim 1, wherein the binding/trapping agent is distributed substantially all of the outer layer. ### Claim 6 (depends on 1) A device as claimed in claim 1, wherein the binding/trapping agent comprises one or more proteins that strongly bind analytes of interest. ### Claim 7 (depends on 1) A device as claimed in claim 1, wherein the binding/trapping agent comprises binding/trapping molecules, for example antibodies. ### Claim 8 (depends on 1) A device as claimed in claim 1, wherein the binding/trapping agent comprises a polymer that strongly binds the analyte. ### Claim 9 (depends on 1) A device as claimed in claim 1, wherein the polymer is nylon or nitrocellulose. ### Claim 10 A device as claimed in, wherein the binding/trapping agent comprises as charcoal or porous carbon. ### Claim 11 (depends on 1) A device as claimed in claim 1, wherein the binding/trapping agent destroys and/or traps the analyte by chemical or biochemical means. ### Claim 12 (depends on 1) A device as claimed in claim 1, wherein outer binding/trapping layer is adapted to create a permanent and uniform diffusion profile from the skin to the outer layer. ### Claim 13 (depends on 1) A device as claimed in claim 1, arranged to cause diffusion of the analyte in a direction substantially perpendicular to the gel/liquid and outer layers. ### Claim 14 (depends on 1) A device as claimed in claim 1, further comprising a measurement device for monitoring the at least one analyte. ### Claim 15 (depends on 1) A device as claimed in claim 1, wherein the measurement device measures the at least one analyte as a function of time. ### Claim 16 (depends on 1) A device as claimed in claim 1, wherein the gel layer has a thickness in the range 10 μm to 1000 μm. ### Claim 17 (depends on 1) A device as claimed in claim 1, where the liquid/gel layer is conductive. ### Claim 18 (depends on 1) A device as claimed in claim 1, wherein the surface area is in the range 1 cm2 to 10 cm2. ### Claim 19 (depends on 1) A device as claimed in claim 1, that is passive. ### Claim 20 (depends on 1) A device as claimed in claim 1, wherein the device is active. ### Claim 21 (depends on 1) A device as claimed in claim 1 comprising means for enhancing permeability or a patient's skin and/or transport of an analyte through the skin. ### Claim 22 (depends on 1) A device as claimed in claim 1, comprising means for applying a current and/or means for applying acoustic energy to the patient's skin. ### Claim 23 (depends on 1) A device as claimed in claim 1 comprising means to physically pierce a patient's skin. ### Claim 24 (depends on 1) A device as claimed in claim 1 comprising means for using a measure of flux rate to calibrate the device. ### Claim 25 (depends on 1) A device as claimed in claim 1 comprising one or more electrodes for measuring skin impedance. ### Claim 26 A method for determining in vivo concentration of an analyte using a transdermal device, the method comprising: measuring skin impedance; measuring flux of an analyte through the skin and using the measured impedance and flux to determine internal concentration of the analyte. ### Claim 27 (depends on 26) A method as claimed in claim 26 comprising measuring the real and/or imaginary part of the skin impedance. ### Claim 28 (depends on 26) A method as claimed in claim 26 comprising measuring the impedance using an electrical signal that has a frequency in the range 100 Hz to 10 KHz. ### Claim 29 (depends on 26) A method as claimed in claim 26 comprising measuring the impedance using an electrical signal that has a voltage in the range of 10 mV to 1V, preferably 100 mV to 600 mV. ### Claim 30 (depends on 26) A method as claimed in claim 26 comprising measuring skin impedance as a function of time. ### Claim 31 (depends on 26) A method as claimed in claim 26 comprising using the measured skin impedance to calibrate the internal concentration of the analyte. ### Claim 32 (depends on 26) A method as claimed in claim 26 comprising using a transdermal device.