A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent....http://www.google.com/patents/US20100081907?utm_source=gb-gplus-sharePatent US20100081907 - Small Volume In Vitro Analyte Sensor and Methods of Making
