Composite membrane containing a cross-linked enzyme matrix for a biosensor
An electrochemical sensor system and membrane and method thereof for increased accuracy and effective life of electrochemical and enzyme sensors.
1. A composite membrane for a biosensor, comprising:
an inner membrane layer comprising a restorable polymerizable membrane, the inner membrane layer adapted to function as an interference rejection membrane;
an outer membrane layer comprising polyurethane, and adapted to be disposed adjacent a flow channel during use; and
an enzyme layer disposed between and in contact with the inner and the outer membrane layers, said enzyme layer comprising a matrix comprising at least one enzyme, a cross-linking agent, and an enzyme stabilizer,
wherein the outer membrane is adapted to control diffusion of an analyte into the enzyme layer.
2. The composite membrane of claim 1 , wherein said enzyme is lactate oxidase.
3. The composite membrane of claim 1 , wherein said enzyme is creatinase.
4. The composite membrane of claim 1 , wherein said enzyme is sarcosine oxidase.
5. The composite membrane of claim 1 , wherein said enzyme is creatininase.
6. The composite membrane of claim 1 , wherein said enzyme comprises a mixture of creatinase and sarcosine oxidase.
7. The composite membrane of claim 1 , wherein said enzyme comprises a mixture of creatinase, creatininase and sarcosine oxidase.
8. The composite membrane of claim 1 , wherein the inner membrane layer has a thickness less than about one micrometer.
9. The composite membrane of claim 1 , wherein the inner membrane has pores sufficiently small to prevent passage of compounds in a sample liquid larger than hydrogen peroxide.
10. The composite membrane of claim 1 , wherein the outer membrane layer has a thickness selected from a range of about 8 to 15 micrometers.