Our ability to understand the brain and treat neurological disorders is largely limited by the lack of tools needed to provide complete and accurate information about neural circuits. Seamlessly integrating nanoelectronic devices with the nervous system will potentially allow us to directly interact with neural circuits. Our research is focused on developing 3D, large scale, flexible nanoelectronic devices with minimized volume and merging them with neuronal systems to provide complete electrical access to neural circuits at single neuron resolution. 

We currently have two venues of research, each focusing on the study of in vivo neural circuits and in vitro neural circuits.

3D neuron cultures for in vitro neural circuit characterization

Significant progress has been made to extend neuronal cultures from 2D into 3D. However, it still remains a great challenge to detect neuronal activity with high spatial and temporal resolution in 3D. The thickness of the structures within conventional 3D neuron cultures are too large for ideal signal detection and may impede neuron growth. Our research efforts in this area are focused on completely mapping the neural activity in the 3D neuron culture space with high temporal and spatial resolution. We will also introduce microfluidic “vasculature” and extend the 3D neuronal culture’s dimensions.

Reliable Chronic Neural Recording

Implanted neural probes are among the most important techniques in both fundamental and clinical neuroscience. Scientifically, they remain our only option to resolve the fastest electrophysiological activities of individual neurons, which provides critical information to dissect the neural circuitry. Clinically, neural electrodes have been successfully used in a number of neurological disorder treatments, such as deep brain stimulation and peripheral nerve stimulation. Further, they allow for the direct communication between brain and man-made devices, which could enable futuristic applications such as human brain-machine interface and neuroprosthetics. Despite great successes and promise, neural electrodes are significantly limited by their unstable performance and substantial invasiveness. Not only its recording can change in timescale as short as minutes, it also induces damages to the brain tissues both acutely and chronically. A reliable neural interface has been pursued for decades, but remains highly challenging. Fundamentally, this instability arises from the distinct physical mismatch at the neural electrode-tissue interface. First, the relatively large size of neural probes compared with tissue components, such as cells and capillaries, induces unavoidable tissue displacement and damage during implantation, and their persistent presence interrupts local biological functions and triggers immune responses. Second, their mechanical stiffness causes poor integration in tissue, and more importantly, strong interfacial forces that elicit sustained tissue responses, neuronal loss, scar tissue accumulation and interface performance deterioration. Recently, our laboratory has created an ultraflexible nanoelectronic neural probe and demonstrated the possibilities of suppressing scarring and achieving reliable long-term neural recording. Furthermore, we used in vivo two-photon imaging to reveal the seamless, subcellular integration of these probes with the local cellular and vasculature networks, including fully recovered capillaries with intact blood-brain barrier, and complete absence of chronic neuronal degradation and glial scar.