A highly sensitive molecular structural probe applied to in situ biosensing of metabolites using PEDOT:PSS

Abstract

A large amount of research within organic biosensors is dominated by organic electrochemical transistors (OECTs) that use conducting polymers such as poly(3,4‐ethylene dioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS). Despite the recent advances in OECT‐based biosensors, the sensing is solely reliant on the amperometric detection of the bioanalytes. This is typically accompanied by large undesirable parasitic electrical signals from the electroactive components in the electrolyte. Herein, we present the use of in situ resonance Raman spectroscopy to probe subtle molecular structural changes of PEDOT:PSS associated with its doping level. We demonstrate how such doping level changes of PEDOT:PSS can be used, for the first time, on operational OECTs for sensitive and selective metabolite sensing while simultaneously performing amperometric detection of the analyte. We test the sensitivity by molecularly sensing a lowest glucose concentration of 0.02 mM in phosphate‐buffered saline solution. By changing the electrolyte to cell culture media, the selectivity of in situ resonance Raman spectroscopy is emphasized as it remains unaffected by other electroactive components in the electrolyte. The application of this molecular structural probe highlights the importance of developing biosensing probes that benefit from high sensitivity of the material's structural and electrical properties while being complimentary with the electronic methods of detection.

Molecular understanding of a π-conjugated polymer/solid-state ionic liquid complex as a highly sensitive and selective gas sensor

“…Optical absorption transition bands are dependent on the doping level of polymers. 22 Under doped conditions, ground-state absorption peaks show significant bleaching as the proportion of the neutral polymer decreases with the concomitant appearance of a broad sub-bandgap absorption known as the polaronic band. 23 The normalised absorbance (see Fig.…”

“…5b and e for neat and blended films, respectively. 9,22,23,[36][37][38] For the neat device, the current increases linearly with the applied field with respect to Ohm's laws. For the blend, however, the current initially increases with respect to the same principle, followed by strong injection current turn-on at À1.3 V resulting in an order of magnitude higher currents compared to the neat P3HT film.…”

In Vitro Models for Studying Respiratory Host–Pathogen Interactions

“…[ 185 ] Of note are poly (3,4‐ethlyenedioxythiophene) doped (p‐type) with poly (styrene sulfonate) (PEDOT:PSS)‐based electrodes or organic electrochemical transistors (OECTs). The detailed physical theory of OECT operation is explored elsewhere, [ 186,187 ] but such technology has been integrated into a variety of biological formats, including Transwell ALI culture, [ 178 ] planar and microfluidic devices, [ 188–191 ] PEDOT:PSS bio‐scaffolds, [ 192,193 ] self‐rolling sensors, [ 194 ] and neuromorphic devices. [ 195 ] In vivo examples include bioresorbable patches [ 196,197 ] and implantable electrocorticography devices for monitoring neuronal epileptiform discharge.…”

PEDOT:PSS-Modified Cotton Conductive Thread for Mass Manufacturing of Textile-Based Electrical Wearable Sensors by Computerized Embroidery

“…This indicates a conformational change in the PEDOT structure as π electron density is shifted towards the intra-ring C-C bonds. [28] Additionally, there was a 4% broadening of the FWHM of the C=C peak. These changes indicate that there is a higher distribution of PEDOT conformations, hence a greater conformational disorder of the PEDOT segments was caused by the embroidery process.…”