## 3 Results
### Enzyme Mixture Impedance Results  
After understanding the impact of trypsin on the impedance of the film-coated sensors compared to the uncoated ones, we then observed how introducing non-specific enzymes to the solution would alter this effect. In Figure 5a, we observe that the addition of amylase and lipase caused a significant decrease in rate of \(\Delta Z\) when added to trypsin, measured at \(6.77\times 10^{-4}\) k\(\Omega\)/min. Further, when amylase or lipase are alone in buffer, we observe the trend of decreasing impedance, opposite to the trend observed with trypsin alone. The origin of the increase in impedance during the first hour of the sensors exposed to lipase.  
Upon Nyquist plot analysis of non-specific enzyme impact (Figure 6), we observe additional trends, opposite again to those from trypsin, induced by amylase and lipase. These trends include a decrease in both the \(45^{\circ}\) tail (representative of the Warburg impedance \(Z_{W}\)) and the radius of the semicircular region (representative of the \(R_{\text{CT}}\)), the latter of which indicates the lack of ion diffusion into the media to account for the increase in exchange current density (\(i_{O}\)) according to Equation (2):  
\[R_{\text{CT}}=\frac{RT}{nFi_{O}} \tag{2}\]  
where \(R\) is the gas constant, \(T\) is the temperature, \(n\) is the number of electrons, and \(F\) is [PERSON]'s constant [25]. This effect on the \(R_{\text{CT}}\) can be a result of the lack of film degradation, or even increase in film thickness [26]. The semi-circular region in the film responding to amylase or lipase is much more defined, indicating a larger double-layer capacitance of the active material, i.e., the film and its constituents. This characteristic of the film is also maintained while there is buffer alone, suggesting the non-specific enzymes do not significantly affect the structure of the film in the absence of trypsin. Alternatively, in the case of most nonspecific enzymes, residual glutaraldehyde remaining in the film may have allowed for accumulation of additional \(\alpha\)-amylase or lipase, likely observed in  
Figure 5: Representative impedance responses at 10 kHz of sensors, either uncoated or coated with a gelatin film, to trypsin, amylase, or lipase, each at 1 mg/mL, or combinations of each enzyme with trypsin. The error bars plot the temporal change in impedance at respective time points (span = 3).  
Section 3.1 [18; 19; 20]. Upon measuring the film after exposure to all three enzymes, we see the similar trend of increasing impedance as when trypsin is alone, though at a much slower pace. We again observe the phenomena of decreasing \(R_{CT}\) in the Nyquist plot, similarly to what occurred with the amylase and lipase alone. The 4-fold reduction in degradation rate may be alleviated by modifying the film to prevent non-specific binding, such as with the use alternative crosslinkers (microbial transglutaminase has shown to be effective), inhibitors (orlistat or tendamistat for lipase and amylase, respectively) or with more specific film materials to trypsin (i.e., poly-L-lysine) [27; 28; 29]. Overall, however, the experiments conducted above allowed us to observe the impacts of these enzymes on the impedance of these gelatin films, and it appeared that the presence of trypsin, rather than the non-specific enzymes, is responsible for inducing these changes in impedance over the film-coated sensors.