Bio-Electronic Fusion: The Living Metal Connection

Advancements in electronics have led to the transformation of rigid systems into adaptive platforms capable of seamlessly interacting with biological environments. Researchers at Binghamton University are at the forefront of developing “living metal” composites integrated with bacterial endospores, facilitating dynamic communication and integration between electronic and biological systems.

In a recent publication in the journal Advanced Functional Materials, Professor Seokheun “Sean” Choi, along with Maryam Rezaie, Ph.D., and doctoral student Yang “Lexi” Gao, present their innovative study on liquid living metal composites that have the potential to redefine the future of bioelectronics.

Professor Choi, from the Department of Electrical and Computer Engineering at the Thomas J. Watson College of Engineering and Applied Science, has been instrumental in bridging the gap between electronic and biological systems through his pioneering technologies.

Prior projects in bioelectronics primarily utilized conductive polymer materials due to the challenges associated with liquid metals. The hydrophobic nature of liquid metals impedes adhesion to electronic substrates, leading to the formation of an oxide layer upon exposure to air or water, restricting electron flow and disrupting communication between electronic and biological systems.

Professor Choi recognized the limitations of polymers, stating, “I was unsatisfied with the interface as it lacked seamlessness. While polymers are conductive, they do not match the conductivity of metal. Moreover, bioelectronics operating in harsh environments are susceptible to mechanical damage and require self-healing properties.”

He believes that the key lies in electrogenic bacteria, which generate small amounts of power. By combining liquid metal with dormant endospores of the Bacillus subtilis bacteria, previously used by Choi for biobattery development, the resulting composite material overcomes many challenges associated with liquid metal alone.

According to Professor Choi, the interaction between the spores and liquid metal droplets is significant, as the chemical functional groups on the spores’ surface disrupt the oxide layers of the liquid metal, enabling conductivity. The spores remain dormant under harsh conditions and germinate in favorable environments. The composite material can be easily integrated into device substrates like paper while retaining the advantageous properties of metal, exhibiting enhanced electrical conductivity upon germination of the spores.

Moreover, the composite material demonstrates self-healing capabilities, autonomously filling gaps in the event of material breakage, a crucial feature for damaged circuits that are challenging to replace.

Further experimentation is required before commercial applications to refine the activation control of endospores and evaluate the stability of liquid living metal composites in various environments over the long term.

Future applications of such materials could enable wearable or implantable devices to interact safely and directly with human tissue, creating seamless integration between biological and electronic systems.

Professor Choi envisions integrating electrogenic bacteria into living electrodes to bridge the gap between molecular and electronic communication, ensuring efficient interaction between the two systems.