A low-cost automatic machine for in-house fabrication of custom microwire-based microelectrode arrays for electrophysiological recordings
Presentation Number: PSTR196.06; Poster Number: VV17;
In-Person Presentation Time: Mon., Nov. 17, 2025 9 – 10:00 a.m.
A piezoelectric inchworm inserter for automatic machine-controlled buckling-free implantation of miniaturized flexible microelectrodes through brain membranes
Presentation Number: PSTR196.10; Poster Number: VV21;
In-Person Presentation Time: Mon., Nov. 17, 2025 9 – 10:00 a.m.
Understanding how the brain works is one of the greatest unsolved scientific challenges of our time. As the BRAIN Initiative 2.0 Strategic Planning points out, “the most ambitious goals from BRAIN 2025, such as recording the activity of 1 to 10 million neurons in a behaving mammal, remain out of reach”. Ultra-miniaturized (< 25 µm diameter) electrodes of soft materials flying under the radar of our immunization system are needed for large-scale chronic recording/stimulation of neural activities. But such devices (e.g. carbon fibers of 7 µm diameter) face challenges due to laborious hand-assembly methods and the need for sophisticated implantation techniques due to the delicate nature. Solving such dilemma requires tissue cutting expertise. Also, human effort needed in a brain-wide recording setup calls for automatic assembly and assistive devices to revolutionize the current labor-intensive implantation process lacking accuracy or repeatability.
MINI Lab’s research in brain machine interface uses our manufacturing expertise to focus on three main aspects: fabrication, implantation, and customization. Our research is dedicated to define the next-generation interface with the optimized body and tip geometry and smallest size possible to reach custom targeted brain areas for chronic recording and/or stimulation with corresponding novel techniques and platforms to enable automatic and repeatable fabrication and minimum-damage implantation of such interfaces.
To improve the current time-consuming manual implantation procedure, we have developed and published a computer-aided designed and 3D printed skull cap system for the pre-digitally-determined implantation locations for each MEA, tailored to custom neuroscience experiment needs. A prototyped 32-channel microwire MEA system was able to record spiking activities over five months through a skull cap. Furthermore, for MEMS-based neural probes, we developed an innovative, cost-efficient, 3D-printed headcap with an embedded microdrive (THEM) system to streamline the manual implantation process for efficient and precise multi-region brain neural-probe implantations. By shifting manual stereotaxic alignment work to pre-surgical preparation of a fully assembled headcap system, incorporating fully preassembled upper support framework for packaging management, and easy customization for specific experiments, our system significantly reduces the surgical time, simplifies multi-implant procedures, and enhances procedural accuracy and repeatability.
To address the labor-intensive assembly challenges of microwire-based microelectrode arrays, especially the state-of-art ultraminiaturized single carbon fiber ones, we have developed an automatic assembly machine guided by computer vision to conduct computer-controlled precise feeding, alignment, and laser cut-off of carbon fiber electrodes.
Chronically implanting microelectrodes for high-resolution action potential recording is critical for understanding the brain. The smallest and most flexible electrodes, most suitable for chronic recordings, are also the most difficult to insert due to buckling against the thin but hard-to-penetrate brain meninges. To address such implantation challenges without introducing further damage to the brain, this project presents our design and prototype of an inchworm-type insertion device that conducts a grip-feed-release incremental motion for planar microelectrode insertion, enabling minimized unsupported length and thus maximized critical buckling load and buckling resistance.
A cantilever beam-based flexible high-resolution system for evaluation of microelectrode force and membrane dimpling depth was developed. The easily duplicable and reconfigurable system was shown feasible for in vivo evaluation of both the pia-only and dura-pia penetration process with either microwires or silicon-based probe shanks. For the first time, we revealed the linear relationship between microwire diameter and membrane rupture force/dimpling depth for in vivo rat brain insertion and for dura penetration.
A laser-based non-contact carbon fiber microelectrode processing method to enable controllable and repeatable production of carbon fiber microelectrode arrays of custom electrode lengths, insulation stripping lengths, and sharpened tips. Compared to conventional labor-intensive manual scissor cutting method, hard-to-control fire torch burning method, and hard-to-mass produce electrical discharge machining method, the laser-based procedure could complete fiber cut-off, tip sharpening, and insulation layer stripping in one path.
MINI Lab’s research in Advanced Manufacturing Processes focuses on collecting and unifying data from all manufacturing aspects at the process level (e.g. product and tooling designs, process parameters and tooling condition, real-time force and temperature recording, product inspection data) to generate theoretical and fundamental understandings of the processes through innovative monitoring methods, numerical modelling, and data analysis. Such understandings help develop new smart manufacturing processes and/or improve current ones and corresponding machine tools for enhanced capabilities, flexibility, and product quality.
Fused filament fabrication (FFF) is the most widely used additive manufacturing process thanks to its low cost and easy setup, but it is limited by low accuracy, poor surface finish, slow build time, and inferior anisotropic mechanical properties. In this study, we conduct experimental studies to investigate the integration of in-process machining with FFF using PLA filaments on a commercial multi-head printer setup. A hybrid FFF with in-process machining test platform with process monitoring capabilities was developed. Tests were then conducted to evaluate the FFF-machining process parameters and integration strategies. The experimental platform development process identified that spindle rigidity and newly printed filament temperature control (e.g., quick cooling with compressed air nozzle) were two key considerations for a high-quality machined surface.
Experimental testbed for hybrid manufacturing process:
Proof-of-concept demonstrations:
The tool-foil thermocouple forms a thermometric junction between the cutting tool and embedded metal foil. As the first technology to provide real-time on-site measurements of the machined surface temperature in hard turning without inverse heat transfer modelling, it scanned the steady-state machined surface temperature at multiple segments, enabling correlation between cutting conditions, tool wear, and machined surface temperature for better product quality and data-based tooling management decisions.
In high-throughput drilling of the compacted graphite iron (CGI), which is a high-strength, difficult-to-machine cast iron for lightweighting applications, the drill temperature and wear are critical for the drilling outcome. As the drill main cutting edges are subject to the high cutting forces, the elevated temperature along the cutting edges greatly impacts the drill life. However, there is a lack of research to predict the spatial and temporal cutting edge temperature distributions as well as its change along the tool wear progression. A tool-foil thermocouple method is adopted in this study to directly measure the drill main cutting edge temperature in high-throughput CGI drilling. Results are cross validated based on a combination of finite element modelling and experimental measurement of the cutting edge temperature from embedded thermocouples 1.0 mm away from the cutting edge. Drilling experiments using the tool-foil measurements show that, along the main cutting edge, the drill center has a higher temperature than that of the outer corner. With increasing drilling depth, the temperature difference along the main cutting edge gradually decreases. Moreover, adhesion-dominated tool wear has changed the cutting edge temperature, leading to higher temperature rise in the middle and outer corner regions along the cutting edge than at the drill center. Similar trend occurs in the drill flank wear, thrust force, torque, and average cutting edge temperature as the number of holes made by the same drill increases.
To identify error sources for cylindricity in finish cylinder boring process, data from multiple sources (design, process, and inspection) needed to be unified and analyzed. This study established a comprehensive cylindricity error prediction and data processing methodology in finish cylinder boring with pioneering inclusion of spindle error data as a dominant factor. Such methodology is implemented at Ford for shortening the ramp-up time of modified engine block designs.
Friction stir extrusion process could extrude lightweight metallic tubing that enhances mechanical and metallurgical properties with respect to traditionally extruded tubular products, critical for lightweight material structures like automotive frames and marine hear exchanger tubes. In a collaborative project led by Lockheed Martin under Manufacturing USA Institute LIFT, pioneering work on experimental temperature monitoring and finite element thermal modelling of the newly developed friction stir extrusion process were conducted.
Biomedical manufacturing is the application of manufacturing technology to advance the safety, quality, cost, efficiency, and speed of healthcare service and research.
MINI Lab’s research in this area utilizes both physics- and data-based modelling to understand the healthcare procedures from manufacturing aspect and make the surgeon-skill-dependent processes “smarter”. Our work on custom assistive device manufacturing evolves the current labor-intensive processes by digitization and additive manufacturing. Our research philosophy to solve these biomedical challenges focuses on a) duplication of clinical practice with engineering measurements to mathematize the problem, b) statistical analysis to identify key factors, and c) theoretical and modelling work to provide solutions.
Tissue cutting procedures in healthcare settings usually involve unrepeatability due to random variables like surgeon’s human error and variance of tissue properties, making statistical analysis an important step to identify key factors. The lab’s expertise in thermal analysis and cutting error identification were perfectly applied to (1) hard tissue (bone) cutting to minimize the temperature rise and chances of thermal necrosis and osteonecrosis through real-time monitoring and quantitative analysis of surgical drilling practice by surgeons and innovative cutting tool design and (2) needle deflection in cancer biopsy through physics-based modelling of cutting tool deformation and needle tip modifications for needle balancing.
Data-driven thermal analysis and tool modification for temperature control in orthopedic surgery
Needle deflection in soft tissue cutting (cancer biopsy)