All solid-state-ion-selective electrodes for real-time measurement of relevant physiological phenomena
Effectively and accurately measuring physiological phenomena in a real-time manner with high fidelity is important for understanding analyte and ion movement on the molecular level. A popular method for interrogating a target analyte is employing the use of ion-selective electrodes (ISE). ISE are a great analytical tool that allows the user to selectively monitor a particular ion or analyte of interest. Liquid-membrane based ISE were among the very first class of ISE to be extensively studied and used. Although these types of ISE possess many favorable properties, several limitations exist. Among these are longevity of the sensor and an inability to easily miniaturize. Leaching of ion-selective membrane (ISM) components, along with poorly defined charge transfer at the electrode interface are among two of the biggest issues plaguing sensor longevity. With the advent of polymer based ISM in conjunction with using highly electroactive conducting polymers (CP), this has given birth to all solid-state ion-selective electrodes (ASSISE). ASSISE are marked by efficient ion to electron transduction as well as having a mechanically rigid ISM that adheres well to the sensor's surface. Coupled with advances in materials science and batch microfabrication processes, miniaturization of ASSISE has become increasingly feasible and cost effective. The work here focuses on an ASSISE called the multi-analyte biochip (MAB). The MAB was employed to monitor photosynthetic activity in the singe-cell green algal Chlorella vulgaris using a bicarbonate/carbonate ion-selective electrode (B/CISE) and hydrogen ion-selective electrode (HISE). The MAB is capable of making a simultaneous multiplexed measurement, thus greatly increasing temporal and spatial resolution. The MAB is a promising analytical tool due to its ease of use and ability to retain its electrochemical integrity after prolonged storage in liquid media. With an increased focus on spaceflight research, the groundwork preformed with C.vulgaris could potentially be taken into a micro-gravity environment to study the effect of reduced gravity on fundamental biological processes. Although the MAB was used to monitor photosynthesis in this work, its versatility enables it to be applied to a wide variety of biomedical, agricultural and environmental research based applications.^
D.Marshall Porterfield, Purdue University.
Biology, Cell|Engineering, Biomedical|Biology, Physiology