Iontronic devices, which use ions like sodium, potassium, and calcium to transmit information, have emerged as a dynamic area in biochemical engineering. These devices promise precise, energy-efficient communication systems for applications such as drug delivery and cell interfacing. However, traditional iontronic devices often rely on rigid structures, limiting their compatibility with soft biological tissues.
In a significant departure, Oxford researchers have engineered dropletronic devices using microscale hydrogel droplets that act as ionic semiconductors. These tiny droplets enable controlled ion movement, akin to electron manipulation in traditional electronics. By assembling droplets with surfactants and linking them using light-activated techniques, the team has created a suite of multifunctional devices, including diodes, transistors, logic gates, and memory modules.
According to Dr. Yujia Zhang, lead researcher from Oxford's Department of Chemistry, "Ions have many advantages over electrons: for instance, the fact they have various sizes and charges means they could be used to achieve various functions in parallel. Through the incorporation of large ionic polymers, we demonstrated a dropletronic device with long-term memory storage, which has not been achieved with previous iontronic approaches and offers an unconventional pathway to neuromorphic applications."
The dropletronic devices exhibit superior efficiency and faster response times compared to other soft iontronic systems while maintaining biocompatibility. Notably, these devices can interface directly with human cells. In their study, the researchers developed sensors capable of recording electrical signals from beating human heart cells, offering potential pathways for advanced biomedical devices.
Dr. Christopher Toepfer, Associate Professor of Cardiovascular Science at Oxford's Radcliffe Department of Medicine, highlighted the implications: "This is the first example of a lab-built biological sensor that can sense and respond to changes in function of human heart cells in a dish. This finding is an exciting step towards the fabrication of more complex biological devices that will sense a variety of abnormalities in an organ and react by delivering drugs intelligently inside the body."
Looking forward, the team envisions dropletronic integration with living tissues, facilitating ionic communication to identify vital molecular species and developing neuromorphic systems for advanced computations. These innovations could revolutionize clinical medicine, enabling precise sensing and intelligent therapeutic delivery.
Professor Hagan Bayley, leader of the research group, commended the multidisciplinary effort: "Dr Zhang has used a creative, highly multidisciplinary approach including aspects of electrochemistry, polymer chemistry, surface physics, and device engineering to produce the first microscale 'dropletronic' devices. The functional capabilities of these structures demonstrate that they might soon be elaborated into practicable devices with applications in both fundamental science and medicine."
Research Report:Microscale droplet assembly enables biocompatible multifunctional modular iontronics