Non-Equilibrium Diffusion Controlled Ion-Selective Optical Sensor for Blood Potassium Determination

Abstract

Blood electrolyte measurements play important roles in clinical diagnostics. Optical ion sensors as simple and elegant as a mercury thermometer are in high demand. We present here an analytical method to quantify potassium ions in undiluted human blood and plasma by measuring the distance or the rate of the color propagation. The sensor was composed of K-selective nanospheres embedded in an agarose hydrogel where mass transport was diffusion controlled. The sensor's color-changing rate and the distance of color propagation depended linearly on the logarithm of K activity. A theoretical model was established and fully supported the experimental findings. This work lays the foundation of a new family of optical ion sensors for direct determination of common blood electrolytes.

The Hofmeister Anion Effect on Ionophore‐based Ion‐selective Nanospheres Containing Solvatochromic Dyes

“…Ion-selective optodes typically contain a H + chromoionophore, an ion exchanger and an ionophore for the target ion. While applications in biomedical fluids and cellular samples have been demonstrated using film and particulate-based optodes, the pH cross-response remains an inherent disadvantage [2]. The pH cross-response comes from the H + chromoionophore, which is a lipophilic pH indicator.…”

Incorporating fluorescent nanomaterials in organically modified sol–gel materials – creating single composite optical pH sensors

“…The dyes were encapsulated with plasticizers or surfactants and form lipophilic particles, then they were embedded in hydrogels and polymers such as polyvinyl alcohol (PVA), 56 polyacrylamide, 57 and agarose. 58 The main difference to our work reported here, is that they mainly focus on hydrogel-based sensor materials that are not stable in industrial applications. The approach based on organically modified silicate materials are more robust, 18 and we hope to be able to use the sensor material reported here to incorporate not only molecular dyes, but also more complex fluorescent materials.…”

Incorporating Fluorescent Nanomaterials in Organically Modified Sol-Gel Materials – Creating Single Composite Optical pH Sensors

“…The dyes were encapsulated with plasticizers or surfactants and form lipophilic particles, then they were embedded in hydrogels and polymers such as polyvinyl alcohol (PVA), 56 polyacrylamide, 57 and agarose. 58 The main difference to our work reported here, is that they mainly focus on hydrogel-based sensor materials that are not stable in industrial applications.…”