Structure–function relationships affecting the sensing mechanism of monolayer-protected cluster doped xerogel amperometric glucose biosensors

Layered Xerogel Films Incorporating Monolayer‐Protected Cluster Networks on Platinum‐Black‐Modified Electrodes for Enhanced Sensitivity in First‐Generation Uric Acid Biosensing

“…Biosensor research is gaining more attention due to its numerous applications that span many different fields. The simplicity and adaptability to different clinically relevant analytes and industrial applications allow electrochemical sensor research to continue at the forefront of this developing technology sector . Enzyme‐based amperometric biosensors offer effective selectivity in the detection of trace amounts of target molecules within complex matrices .…”

“…Hydrogen peroxide is subsequently oxidized/reduced at a working electrode surface to yield a current response proportional to analyte concentration. Such biosensors have the advantage of affordability and simplicity, while also allowing for relatively easy modification to a plethora of target analytes and possibility of miniaturization for in vitro and in vivo clinical applications …”

“…The MPC‐doped sensor showed an order of magnitude increase in sensitivity, doubled linear range, and fourfold decrease in response times compared with similar films without MPC doping. A subsequent report established that the MPC network allowed for a decreased dependence on diffusion and a fast electron reporting system throughout the film; these factors significantly enhanced the sensitivity . Although signal enhancement was ultimately achieved, the scheme suffered from less than optimal selectivity in discriminating against common interferents.…”

Layer-by-layer design and optimization of xerogel-based amperometric first generation biosensors for uric acid

“…In enzyme-based biosensing schemes, it is thought that higher concentrations of certain enzymes permit the rate of substrate conversion to become independent of enzyme concentration [34]. The linearity of the results of the calibration curves, both in testing the enzyme species and loading as well as in subsequent calibration curves to be presented, suggests that the 3-4 mg UOx doping level within the xerogels represents an excess of available UOx and allows the system to avoid saturation effects that cause non-linearity and calibration curve plateau which would necessitate Michaelis-Menton kinetic measurements [42,43]. Additionally, the linear response overlaps well with the relevant physiological concentration range of UA, suggesting that UOx activity is not a factor in these sensing schemes.…”

“…While dampening the signal, these layers provide physical stability and electrode-to-electrode consistency, insulating the current response from variations in enzyme loading. These layers appear to regulate the diffusion of UA substrate to the enzyme as evidenced by the absence of saturation behavior in the calibration curves over the targeted concentration range, a result suggesting mixed kinetic and diffusional control of the signal production [42]. Strategies for enhancing the magnitude of the signal in these film systems are currently being explored.…”