Multi-enzymatic biosensors and stabilization of multi-enzymatic biosensors at room temperature

A biosensor comprising:

• an electrode;
• a plurality of enzymes immobilized over the electrode, where an interaction among at least two of the plurality of enzymes can cause instability of one or more of the plurality of enzymes;
• a diffusion barrier on the plurality of enzymes;
• and
• a polysaccharide that is (i) applied to the diffusion barrier of the electrode, (ii) included with the enzymes immobilized over the electrode, or (iii) both applied to the diffusion barrier of the electrode and included with the enzymes immobilized over the electrode, the polysaccharide for maintaining stable activity of the one or more of the plurality of enzymes.

A method of using a multi-enzyme biosensor, the multi-enzyme biosensor comprising:

• a plurality of enzymes in an enzyme solution over a surface of an electrode, where an interaction among at least two of the plurality of enzymes can cause instability of one or more of the plurality of enzymes;
• a diffusion barrier on a surface of the plurality of enzymes;
• and
• a polysaccharide solution (i) applied to the electrode after the diffusion barrier is applied to the surface of the plurality of enzymes, or (ii) added to the enzyme solution before the enzyme solution is applied over the electrode, or (iii) both added to the enzyme solution before the enzyme solution is applied to the electrode and applied to the electrode after the diffusion barrier is applied over the surface of the plurality of enzymes, the polysaccharide solution maintaining stable activity of the one or more of the plurality of enzymes;
• wherein the method comprises using the multi-enzyme biosensor to measure creatine, creatinine, or both creatine and creatinine in a body fluid sample.

A disposable cartridge comprising multi-enzyme sensors, where a multi-enzyme sensor among the multi-enzyme sensors comprises:

• an electrode;
• a plurality of enzymes immobilized over the electrode, where an interaction among at least two of the plurality of enzymes can cause instability of one or more of the plurality of enzymes;
• a diffusion barrier on the plurality of enzymes;
• and
• a polysaccharide that is (i) applied to the diffusion barrier of the electrode, (ii) included with the enzymes immobilized over the electrode, or (iii) both applied to the diffusion barrier of the electrode and included with the enzymes immobilized over the electrode, the polysaccharide for maintaining stable activity of the one or more of the plurality of enzymes.