Ⅰ. Microneedle Electrodes and Their Applications
Microneedle electrodes are microscale needle-like devices that can partially or completely penetrate the skin surface to collect electrophysiological/electrochemical signals or achieve electrical stimulation. They are widely used in wearable/implantable sensors, neuroscience, and brain-computer interfaces. Their core advantage is the ability to continuously detect in vivo physiological and pathological parameters such as electrocardiograms and electromyograms, providing direct and accurate data for diagnosis and treatment.
The Utah electrode array, developed by the University of Utah, is a representative technology in microneedle electrode arrays. Its unique three-dimensional needle-like structure allows each electrode to possess both high spatiotemporal resolution and excellent insulation. After implantation, the electrode tip acts only on the surrounding neuronal group, and can even record the firing of a single neuron. With the development of MEMS technology, microneedle electrode arrays have seen significant improvements in biocompatibility, mechanical flexibility, long-term stability, and resolution.
Ⅱ. Electrophysiological Signal Acquisition Solutions
In the biomedical field, the acquisition and analysis of electrophysiological signals are crucial for disease diagnosis and health assessment. However, these signals are complex and weak, making effective acquisition a persistent challenge. Currently, there are two main solutions: implantable and wearable.
Implantable solutions involve directly implanting a microneedle electrode array into the human body to achieve real-time continuous monitoring of electrophysiological signals. Its advantages lie in high spatiotemporal resolution and stability, accurately capturing the firing activity of individual neurons. However, it also presents challenges such as surgical risks, insufficient long-term stability, and biocompatibility issues.
Wearable solutions prioritize convenience and comfort. By embedding microneedle electrode arrays on the skin surface or inside clothing, users can easily monitor electrophysiological signals. This solution eliminates the need for surgery, reducing risks and improving ease of use and comfort. However, it still faces technical challenges such as signal interference and noise suppression that require resolution.
Ⅲ. Applications of Microelectrodes in Neuromedicine
Microelectrode array technology, as a key tool for electrophysiological signal acquisition, plays a vital role in neuromedicine and brain-computer interfaces. By implanting or wearing microelectrode arrays on the human body, scientists can monitor neuronal firing activity, electroencephalogram (EEG) signals, and other electrophysiological signals in real time, thus providing strong support for the diagnosis and treatment of neurological diseases. Simultaneously, microelectrode array technology has also brought new breakthroughs to the development of brain-computer interface technology, making it possible for humans to control external devices through thought.
Ⅳ. Polymer Flexible Microneedle Dry Electrodes
Based on polymers, flexible microneedle dry electrodes are ingeniously designed to effectively monitor neural electrical signals, providing new tools for neuromedical research. This technology not only improves the efficiency of electrophysiological signal acquisition but also offers new possibilities for the early diagnosis and treatment of neurological diseases.