Determination of sodium and potassium ions in patients with SARS-Cov-2 disease by ion-selective electrodes based on polyelectrolyte complexes as a pseudo-liquid contact phase

Abstract

Nowadays, there are several methods for the detection of various bioelements during SARS-CoV-2. Many of them require special equipment, high expenses, and a long time to obtain results. In this study, we aim to use polyelectrolyte multilayers for robust carbon fiber-based potentiometric sensing to determine the ion concentration in human biofluids of COVID-19 patients. The polyethyleneimine/polystyrene sulfonate complex is hygroscopic and has the ability to retain counterions of inorganic salts. This fact makes it possible to create a flexible ionometric system with a pseudo-liquid connection. The formation of the polyethyleneimine/polystyrene sulfonate complex allows for the adhesion of a hydrophobic ion-selective membrane, and creates a Nernst response in a miniature sensor system. This approach discloses the development of miniaturized ion-selective electrodes and their future application to monitor analyte changes as micro and macroelement ions in the human body to identify correlation to SARS-CoV-2. An imbalance in the content of potassium and sodium in urine and blood is directly related to changes in the zinc content in patients with coronavirus. The proposed method for assessing the condition of patients will allow fast determination of the severity of the course of the disease.

Fig. 1. Scheme of the electroanalysis of ions in blood and urine by ion-selective sensors.

Fig. 2. The carbon fiber modification by the polyelectrolyte LbL assembly (a), common scheme of the ion-selective electrode (b).

Fig. 3. The SEM images of the CF electrodes modified with polyelectrolytes before (a and b) and after (c) potentiometric measurements.

Fig. 4. Potentiometric response for potassium (a) and sodium ions (c) on ISEs and corresponding calibration plots after addition of the standard solution (y = −41.8x + 37.4, n = 3, p = 0.95; y = 43.2x + 186.0, n = 3, p = 0.95) (b and d).