Monitoring method and/or apparatus
View Patent ↗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.
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.