Photonic Crystal-Based Sensing and Imaging of Potassium Ions

Abstract

We report on a method for selective optical sensing and imaging of potassium ions using a sandwich assembly composed of layers of photonic crystals and an ion-selective membrane. This represents a new scheme for sensing ions in that an ionic strength-sensitive photonic crystal hydrogel layer is combined with a K +-selective membrane. The latter consists of plasticized poly(vinyl chloride) doped with the K +-selective ion carrier, valinomycin. The film has a red color if immersed into plain water, but is green in 5 mM KCl and purple at KCl concentrations of 100 mM or higher. This 3D photonic crystal sensor responds to K + ions in the 1 to 50 mM concentration range (which includes the K + concentration range encountered in blood) and shows high selectivity over ammonium and sodium ions. Sensor films were also imaged with a digital camera by exploiting the RGB technique.

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“…Hence, this property makes them suitable as materials for use in sensing technologies. Fenzl et al published several works on the use of photonic crystal as sensors for sensing ionic strength [143], potassium ions [144], organic solvents in water [145], and acetylcholine/acetylcholinesterase inhibitors [146]. Hoi et al reported a technique to fabricate photonic chips that can integrate colloidal crystals, optical fibres and microfluidic channels for lab-on-a-chip devices.…”

30 s Response Time of K+ Ion‐Selective Hydrogels Functionalized with 18‐Crown‐6 Ether Based on QCM Sensor

“…Hence, rapid detection of high potassium concentration in the blood is essential for treating wounded individuals. Potassium monitoring is also of great interest in point‐of‐care diagnostics and is routinely used in the hospital intensive care units (ICUs), where high potassium concentrations (>7.0 × 10 −3 m ) in serum can lead to cardiac arrests and even death . It is also an important parameter in predicting the occurrence of infarcts .…”

“…Potassium monitoring is also of great interest in point‐of‐care diagnostics and is routinely used in the hospital intensive care units (ICUs), where high potassium concentrations (>7.0 × 10 −3 m ) in serum can lead to cardiac arrests and even death . It is also an important parameter in predicting the occurrence of infarcts . Rapid, real‐time, and continuous measurement of potassium ion concentration is crucial when patients are monitored in physiological ranges.…”