The shelf-life of biosensors were tested after they were incubated at 4 or 25∘C in nontransparent plastic bottles in order to prevent direct light exposure because both DTNB and ATCh are light sensitive molecules. As seen in Figure 5(d), the biosensor response to ATChI decreased to about 40% in one week at RT and to about 50% at 4∘C when glucose was included in sensor mixture. The 4∘C storage maintained the biosensor efficiency at a constant around 50% up to 60 days. Similarly, room temperature storage maintained around 20% activity.