Designing Sensitivity: A Comparative Analysis of Microelectrode Topologies for Electrochemical Oxygen Sensing in Biomedical Applications

Abstract

The monitoring of dissolved oxygen is a key parameter in many fields, namely the treatment and monitoring of various cerebral traumas. Leveraging existing manufacturing techniques, electrochemical sensors hold the potential for compact, simple, and scalable dissolved oxygen sensors. Past studies have focused on the general design of such sensors, but a comparative study on the impact of microelectrode geometries for cerebral applications has been forthcoming. We present here the results of a characterization study conducted across solid-state sensors with varying microelectrode geometries. The electrode structures were covered with a Nafion membrane and included variations of the classic interdigitated microelectrode array in addition to a circular microelectrode array variation. Voltage sweeps were conducted while monitoring the devices’ sensing current responses across a 50.3 mmHg change in dissolved oxygen within a deionized aqueous solution. Half of the devices were identified as ultramicroelectrode designs that presented a greater dependence on electrode spacing and topology. The ultramicroelectrode-style (UME) interdigitated electrode (IDE) topology presented the greatest signal response at 25.24 nA/mmHg, an approximate eight-fold improvement in sensitivity from a non-UME variation with a sensitivity of 2.98 nA/mmHg. The design presented a linear response from 8.3 mmHg to 58.6 mmHg with r2 = 0.9743. The sensitivity improvement was attributed to the ultramicroelectrode structure’s amplifying diffusive feedback, which was enabled by the IDE topology and short electrode spacings.

Electrically Controlled Click‐Chemistry for Assembly of Bioactive Hydrogels on Diverse Micro‐ and Flexible Electrodes

“…In this geometry, diffusion of electrochemically generated protons is radial and results in the formation of a sphere of gel growing from the microelectrode tip. [ 27–29 ] We observe a linear growth of the radius of the sphere with time and total charge density (Figure 3c,d). An inflection point at 1 s (−3.3 mC mm −2 ) indicates a decrease in the growth rate from 695 ± 89 (−2015 ± 75 mm 3 mC −1 ) to 399 ± 50 µm s −1 (−902 ± 20 mm 3 mC −1 ).…”

Emergence of integrated biosensing-enabled digital healthcare devices

“…Table 1 lists some innovative designs and methods reported for the development of sensor technologies. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Understanding various mechanisms through methodogical investigation is important. Here, 3D printed CNT electrodes, distinct interaction, Janus 2D materials, biomimetic receptor, pH-sensitive drug sensing, hematopoietic stem cell differentiations are some of the unique processes involved in developing methods for sensing purposes.…”

“…Biosensing materials, designs, and procedures Biosensor designs are based on integrating diverse elements, including electronics, structural, and computational aspects, as well as spectroscopic methods, electrodes, and thermoresponsive sensing analytes, often each with a unique mechanism. [20][21][22][23][24][25] Diverse methods of detection, such as photolithography, imaging, cardio-mechanical signal detection, posture detection based on wearable devices, selfpowered tetherless detection, and silicate-based electroconductive mechanisms, are used in different studies. [26][27][28][29][30][31] They offer a solution to issues related to the lifethreatening potential by the delayed treatment of diseases and complications due to the fact that not all segments of human society have the financial means to pay for such specialized diagnoses.…”