Monitoring method and/or apparatus

• US 7,415,299 B2
• Filed: 04/19/2004
• Issued: 08/19/2008
• Est. Priority Date: 04/18/2003
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Zimmermann, Stefan, Liepmann, Dorian, Pisano, Albert, Stoeber, Boris
• Primary Examiner(s): Nasser, Jr.; Robert L.
• Assistant Examiner(s): Toth; Karen E
• Application Number:
  US10/828,510
• Publication Number:
  US 20060211933A1
• Time in Patent Office: 1,583 Days
• Field of Search: 600/345, 604/29, 604/207, 604/210, 604/4.01, 604/5.01, 604/5.04, 604/6.09, 210/195.2, 21032175-3218, 210/348, 210/500.1, 210/500.21
• US Class Current: 600/345
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/14525 using microdialysis
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase

Abstract

A method and apparatus for substance monitoring. One application is an easy to handle continuous glucose monitor using a group of hollow out-of-plane silicon microneedles to sample substances in interstitial fluid from the epidermal skin layer. The glucose of the interstitial fluid permeates a dialysis membrane and reaches a sensor. Using MEMS technology, for example, allows well-established batch fabrication at low cost.

Claims

1. A method of monitoring glucose disorders comprising:

preparing a plurality of out-of-plane microneedles for applying to the skin of a subject with a dialysis membrane remaining outside the skin;

fixing a detecting substance useful in determining glucose levels on an opposite side of said dialysis membrane from said needles;

wherein said fixing is accomplished by placing a polymer-detecting substance solution at said opposite side of said membrane after higher temperature fabrication and/or assembly steps of said microneedles have been performed;

applying said plurality of out-of plane microneedles to the skin of a subject with a dialysis membrane remaining outside the skin; and

performing continuous glucose monitoring by testing composition of a dialysis fluid remaining outside the skin and separated from said microneedles by said dialysis membrane.

2. The method of claim 1 further comprising:

said microneedles comprising a plurality of dialysis membranes on a side opposite a side applied to said surface such that said membranes are not placed under said surface.

3. The method of claim 2 further wherein:

said plurality of dialysis membranes comprise a large total membrane surface that remains outside of said internal region.

4. The method of claim 1 further wherein:

a plurality of said microneedles are pre-filled with a fluid before said applying.

5. The method of claim 1 further wherein:

said microneedles are long enough to prestress a region of the surface at a needle lumen; and

further comprising;

applying high pressure to a small local surface region through said microneedles to cause rupture of the cell matrix to open a connection between fluids inside a needle lumen and bodily fluids underneath the broken skin layer; and

using said connection to sample one or more substances of interest at and/or just below said surface.