Potentiomics: Observations of In Situ and In Vitro Microbial Metabolic Activity Using Type IV Non-Selective Biofilm Membrane Potentiometric Sensors in Real-Time Applications.

Potentiometric instrumentation technologies are widely used across many disciplines of science and engineering providing the ability to measure changes to specific environmental variables through various types of sensor electrodes and selective membranes. However, types I, II, and III potentiometric sensor electrodes are limited by biofouling activity, membrane maintenance, grounding sensitivity, thermodynamic variables, and electromagnetic interference. Further, algorithms embedded into instrumentation hardware have impeded the usefulness of such measurements outside of highly controlled environments. Reliability of accurate measurement using these types of senor electrodes is limited to industrial and lab applications in chemistry and nominally active biological environments. Novel innovations in using exotic materials have improved the usefulness of Type II (e.g. tantalum-rubidium-doped titanium) and Type III (e.g. Nafion™ membranes) sensor electrodes, but those sensors are still limited to measuring a single selective parameter. This scope of work investigates utilizing a novel non-selective membrane, or naturally occurring biofilm membrane, as the active sensing surface of a graphite electrode as a new Type IV potentiometric sensor electrode (e.g., the MiProbE™) in biologically active environments. The analysis herein demonstrates decomposition of these non-selective signals into real-time metabolic activity, measurement of key biochemical processes and environmental condition parameters through classical mathematical analysis methods providing the basis of Potentiomics – the characterization and quantification of biochemical metabolic processes in highly dynamic non-equilibrium states.