Journal of Materials Chemistry B & C joint themed issue: organic bioelectronics

Christopher J. Bettinger

Natalie Stingelin

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Organic bioelectronics is an interdisciplinary research field that uses materials science, chemistry, physics, biology and engineering to create new knowledge and novel opportunities with respect to how electrical signals generated by organic electro-active materials can be translated into bio-signals and vice versa. This capability requires optoelectronic properties of abiotic–biotic interfaces to be measured and manipulated, and enables exciting new technologies such as in vitro biosensors, electronic medical implants, neuroprostheses, and many other devices for medicine and beyond. Because of this promise, the field of organic bioelectronics continues to grow rapidly.

Research activities in bioelectronics are supported through fundamental discoveries in the synthesis and characterization of materials with unique properties, including optoelectronic, mechanical and biofunctional functionalities. These organic compounds typically play an integral role as active materials as they often strongly determine device function. Microelectronic device fabrication has also matured sufficiently to enable the plethora of novel bioelectronics materials to be characterized. Moreover, materials processing and device manufacturing techniques previously invented for organic semiconductors can be leveraged to process many biologically-derived materials. Most excitingly, the scope of prospective applications for organic bioelectronics has expanded rapidly. Many initial applications in organic bioelectronics focused on biosensor technologies for the in vitro detection of biomolecules such as antibodies, proteins, and DNA. Next-generation devices offer unique capabilities for continuous in vivo monitoring, electronic manipulation of cell behavior, ionic and protonic logic, electronically active controlled release, and next-generation brain–machine interfaces. Prospective applications will expand with increasing interest in physiology, neuroscience, and the desire for early disease detection and treatment.

The rapid proliferation of research activities in the intrinsically interdisciplinary organic bioelectronics field has inspired us to organize this themed issue, which spans two journals: Journal of Materials Chemistry B & C—reflecting the philosophy of high multidisciplinarity found in this exciting and rapidly growing area. The topics of this themed issue can be loosely categorized into novel materials for organic bioelectronics, techniques for materials processing, and prospective applications. It also highlights many recent advances in both natural and synthetic materials for organic bioelectronics.

Electronically active natural materials include proteins, polysaccharides, small aromatic molecules, hydrogen-bonded compounds, pigments and dyes. These materials exhibit a wide range of charge transport properties. There are many examples of synthetic and hybrid natural–synthetic materials for bioelectronics including conducting polymers, graphene derivatives, oligomeric thiophene-based conjugates, and polydopamine melanin analogues. The electrical, mechanical, and chemical properties of many of these materials are discussed in great detail. Taken together, these studies provide valuable insight into the structure–property relationships of many materials that have potential utility in organic bioelectronics devices.

Multi-scale materials processing is another prominent theme for this themed issue. Self-assembly of nanostructures using both natural and synthetic templates is, for instance, an important aspect when processing bioelectronics materials into architectures that can be used in polymer-based devices and organic–inorganic composites. Deterministic structures can be produced using processes such as nanoprinting via dip-pen nanolithography and 3D printing, both of which are techniques discussed within this themed issue, too. Scalable manufacturing of bioelectronic materials is another important consideration in the field, aimed at enabling device fabrication at high volumes or into formats with large areas. Devices may need also to be fabricated into complex architectures or flexible electronics platforms, which are additional central themes in advancing bioelectronics that can be leveraged to advance the functionality of organic bioelectronics. These activities are broadened by use of proton-conducting biopolymers, which can be fabricated into field-effect devices and memristor electronics.

The prospective application space of organic bioelectronics is vast, ranging from in vitro biosensing to brain–machine interfaces. Biosensors are a highly active area of research in organic bioelectronics that is well-represented in this issue. Topics include materials for optical biosensing and strategies to improve the sensitivity and stability of transistor-based biosensors. Functional substrate materials that control protein adsorption and cell binding through applied voltages could lead to new strategies for dynamic in vitro cell culture platforms. Brain–machine interfaces are yet another exciting technology that can benefit directly from recent advances in bioelectronics.

There are many other topic areas in organic bioelectronics that are worthy of inclusion, but were omitted due to space restrictions. As guest editors of this themed issue, we would like to thank all the authors for the high quality of the contributions. Furthermore, we would like to thank the editorial staff from Journal of Materials Chemistry B & C for their guidance and support throughout the creation process. It is our hope that researchers in chemistry, biology, physics and beyond will enjoy reading these articles and use them as a springboard to usher in the next generation of organic bioelectronics devices.

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