SoftBCI

Brain–Computer Interfaces (BCIs) enable direct interaction between neural activity and electronic systems and are increasingly relevant for neuroprosthetics, human–machine interaction, and the treatment of neurological disorders. While advances in neural signal acquisition and processing have accelerated progress in this field, the long-term reliability of implantable neural probes remains a critical challenge. Conventional silicon-based interfaces exhibit a strong mechanical mismatch with brain tissue, leading to immune response, degradation of signal quality, and limited operational lifetime. This Seed Project proposes the development of a stiffness-adaptive neural interface that combines soft-matter materials with miniaturised electronic circuits for neural data acquisition and transmission. The probe is engineered to be mechanically rigid during implantation and to autonomously transition into a soft, brain-compliant state after insertion. This adaptive mechanical behavior enhances long-term tissue compatibility while preserving stable electrical performance. The stiffness transition is enabled by a substrate that, in its dry state, forms a sharp and rigid probe capable of penetrating brain tissue, but rapidly transforms into an ultrasoft material—mechanically comparable to brain tissue—upon exposure to the hydrated neural environment. The electrodes and interconnects are based on a proprietary liquid-metal composite, deposited and micropatterned using microfabrication and soft-lithography techniques, followed by biocompatible electrode surface modification. This stretchable liquid-metal composite maintains robust electrical conductivity under mechanical deformation and hydration-induced swelling, enabling stable neural interfacing throughout the stiffness transition and during in vivo operation. At the system level, the project focuses on integrating the soft probe with compact electronic interfaces, including low-noise signal conditioning, scalable electrode interconnect architectures, and wireless communication to a wearable, head-mounted unit. Within the scope of this exploratory project, emphasis is placed on demonstrating material–electronics co-design, electrical functionality, and compatibility with existing neural recording platforms, while establishing the technical foundations for future fully wireless operation. The head-mounted wearable helmet, based on a previously developed and published design from our group, enables the integration of multiple soft probes. This architecture allows simultaneous neural recording from multiple brain regions when required, in contrast to current state-of-the-art systems that are typically limited to single-region access. In the longer term, this approach aims to enable high-resolution, durable neural interfaces capable of stable, long-term neural data acquisition across multiple brain regions. By tightly integrating adaptive materials, microelectronics, embedded systems, and communication architectures, the project is aligned with objectives of European chip act, and CMU-Portugal ICT technologies, and lays the groundwork for transformative BCI technologies with impact in digital health and human–machine interaction.