Direct Electrochemical Signaling in Organic Electrochemical Transistors Comprising High-Conductivity Double-Network Hydrogels.
Alex C TsengToshiya SakataPublished in: ACS applied materials & interfaces (2022)
In composite hydrogels, the high electrical performance of poly(3,4-ethylenedioxythiophene) complexed with poly(styrenesulfonate) (PEDOT:PSS) is integrated with complementary structural and electrochemical functions via a rationally designed poly(acrylamide) second network incorporating phenylboronic acid (PBA). Free-standing double-network hydrogels prepared by a simple one-pot radical polymerization exhibit state-of-the-art electrical conductivity (∼20 S cm -1 in phosphate buffered saline) while retaining a degree of hydration similar to that of biological soft tissues. Low resistance contacts to Au electrodes are formed via facile thermo-mechanical annealing and demonstrate stability over a month of continuous immersion, thus enabling hydrogels to serve as channels of organic electrochemical transistors (OECTs). Despite thicknesses of ∼100 μm, gating of hydrogel OECTs is efficient with transconductances g m ∼ 40 mS and on/off ratios of 10 3 in saturation mode operation, whereas sufficiently high conductivity enables linear mode operation ( g m ∼ 1 mS at -10 mV drain bias). This drives a shift of sensing strategy toward detection of electrochemical signals originating within the bulky channel. A kinetic basis for glucose detection via diol esterification on PBA is identified as the coupling of PBA equilibrium to electrocatalyzed O 2 reduction occurring on PEDOT in cathodic potentials. Hydrogel OECTs inherently amplify this direct electrochemical signal, demonstrating the viability of a new class of soft, structural biosensors.
Keyphrases
- label free
- gold nanoparticles
- drug delivery
- hyaluronic acid
- molecularly imprinted
- ionic liquid
- tissue engineering
- wound healing
- reduced graphene oxide
- extracellular matrix
- mass spectrometry
- drug release
- gene expression
- type diabetes
- skeletal muscle
- blood pressure
- quantum dots
- water soluble
- loop mediated isothermal amplification
- blood glucose
- high resolution
- insulin resistance
- carbon nanotubes