Themed collection Bioelectronics

Guest editors Christopher J. Bettinger and Natalie Stingelin introduce this Journal of Materials Chemistry B & C joint themed issue on organic bioelectronics.

Organic bioelectronics offers important opportunities to study complex biological systems, such as neural networks, and develop new biomedical tools for the diagnosis and treatment of brain diseases.

We highlight our recent efforts in developing devices that control the flow of H⁺ and OH⁻ in biological polymers.

Current issues/challenges in the development of biocompatible eumelanin-based devices ranging from commercial eumelanins through 5,6-dihydroxyindole polymers to mussel-inspired polydopamine are presented.

Amyloid-directed assembly of nanostructures and amyloid-enabled functional devices are highlighted to show the promise of amyloids for future bionanoelectronics.

The carbon framework common to both organic semiconductors and biological structures suggests that these two classes of materials should be easily integrated.

Two dimensional nanosheets have great potential as conductive and/or flexible elements in biomaterials.

Chemical manipulations of the photosynthetic bacterial reaction center for the implementation of this photoenzyme into bioelectronic devices are overviewed.

Electronic biosensing is a leading technology for determining concentrations of biomolecules.

Well-designed metal nanostructured arrays hold great advantages for on-chip label-free plasmonic biosensing, meeting the need for portable and rapid diagnosis.

This review charts the development of dip-pen nanolithography (DPN) for the fabrication of nanoscale bioelectronic and biomaterial interfaces.

Organic bioelectronics for dynamic modulation of normal and infected tissue microenvironments, and the development towards fully automated cell culture systems.

Blue laser photoelectrically and photothermally exciting a wireless carbon fiber electrode to activate a nearby neuron.

Conducting polymer hydrogels (CPHs) are conducting polymer-based materials that contain high water content and have physical properties, resembling the extracellular environment.

We have investigated protein fibrils decorated with metallic polymers using conductive AFM.

The skin morphology of cephalopods endows them with remarkable camouflage capabilities. Herein, we report infrared invisibility stickers inspired by the structures and proteins found in cephalopod skin. These stickers enable arbitrary objects to acquire reconfigurable infrared camouflage patterning. Our work represents an initial step towards wearable biomimetic infrared stealth technologies.

We report the preparation and characterization of films of electroactive supramolecular polymers based on non-electroactive oligoalanines and electroactive oligoanilines.

A PEDOT:PSS based sensor for continuous electronic monitoring of epithelial barrier formation and disruption compatible with microscopy.

Two azide-functionalized AIE fluorogens are synthesized and used for detecting S-phase DNA synthesis and cell proliferation based on EdU assay.

Multiphoton microfabrication was used to prepare CP-based materials for drug delivery and stimulating tissues.

Switchable interfaces can deliver functionally reversible reactivity with their corresponding analytes, which allows one to positively respond to the activity of biological elements, including enzymes and other biomolecules, through an encoded stimulus.

Polythiophene/water interfaces are investigated by sum frequency generation spectroscopy and molecular dynamics simulations, showing a preferential edge-on molecular orientation.

High resolution monitoring of cell layer integrity with the OECT was up until now, limited to high resistance, barrier tissue type cells. In this work, the sensitivity and versatility of the device is expanded to monitor all adherent cell types.

Incubation of PANI films in physiological conditions leads to deprotonation and loss of dopant from the polymer backbone.

A simple method is presented for the preparation of photostable phosphorescent polymer nanospheres.

Electrolytes consisting of mixtures of phosphonium ionic liquids and water lead to high ON/OFF ratios in organic electrochemical transistors making use of activated carbon gates.

We report on bioconjugation strategies to functionalize hydrogen-bonded pigment semiconductors with proteins, and demonstrate hybrid bioelectronics devices operating under aqueous conditions.

The sensitivity of OECT-based epinephrine sensors has been dramatically improved by modifying carbon nanomaterials on the Pt gate electrodes.

A roll-to-roll process is reported for the preparation of free-standing conductive polymer nanosheets on large areas. Nanosheets are transferred in conformal contact with target surfaces (including skin) and act as unperceivable bio-electrodes.

Polycysteinyldopamine (pCDA), a polydopamine-like polymer with ionic conductor behaviour, can be used for dip-coating various surfaces with pro-oxidant thin films.

A novel PEDOT-ionic liquid polymer coating was synthesized for improving the performance of MEAs implanted in the brain.

An investigation of how systematic variation of peptide sequence influences the nanoscale and bulk properties of 1D-nanostructure forming peptide–π–peptide hydrogelators is reported herein.

3D conducting polymer-based bioelectronic interface (BEI) devices for dynamically controlling circulating tumor cell capture/release performance through the cyclic potential of electrical stimulation.

We present a reference-electrode free, all organic K⁺ sensitive ion sensing platform fabricated by simplest means on a plain sheet of paper.

We show that protein specific tailoring of membrane forming ABA polymers is necessary for optimal pore-based biosensor performance.

By mixing a PEDOT:PSS suspension with the modified biopolymer carboxymethylated dextran (CMD), we obtain conductive films displaying carboxyl (–COOH) groups allowing for covalent grafting of proteins via amide bonds.

Scanning electron microscope image of surface morphology of conducting polymer PEDOT doped with bioactive molecules.

Eumelanin and graphene-like integration towards a competitive exploitation in the materials science of the melanic human pigment.

Ice-templating of the conducting polymer PEDOT:PSS yields 3D tissue-mimicking scaffolds that can electrically control protein conformation and various cell functions.

A sensitive EGOFET biosensor fabricated by anchoring bioprobes through a UV crosslinked poly(acrylic acid) coating deposited on an organic semiconductor.

A low-noise measuring system was developed to accurately detect minute membrane capacitive current oscillations across populations of C6 glioma cells.

PEDOT:PSS films are integrated in a flexible neural implant to safely transduce electrical pulses to stimulate the auditory brainstem.

Post-polymerization functionalization using thiol–ene “click” chemistry provides an effective, convenient means to modify the surface properties of conjugated polymers such as poly(3,4-propylenedioxythiophene) (PProDOT).

With increasing amounts of EPh crosslinker, PEDOT-co-EPh copolymer thin films change colors from blue to red, show reduced charged transport, become mechanically stiffer, and remain cytocompatible.