Applications and prospects of 3D conductive polymer micro-nano electrodes in brain organoid research

<sec><p indent="0mm">Brain organoids, derived from stem cells under three-dimensional (3D) culture conditions, have become transformative tools in neuroscience research. These organoids replicate key aspects of human brain development and neural activity, making them invaluable models for studying neurodevelopmental disorders, neurodegenerative diseases, and drug screening. By mimicking the complex 3D structure of the human brain, organoids enable researchers to study intricate neural interactions and disease mechanisms that are difficult to capture in traditional two-dimensional (2D) cell cultures. However, the 3D architecture of organoids poses significant challenges for conventional electrode systems, which are primarily designed for flat, 2D environments. These traditional electrodes struggle to penetrate deep into the internal layers of organoids, limiting their ability to comprehensively monitor neural signals or deliver precise electrical stimulation. This challenge highlights the need for advanced 3D micro/nano electrodes designed specifically for use in brain organoids. </sec><sec> In response to these challenges, researchers have developed 3D conductive polymer-based micro/nano electrodes that offer distinct advantages for brain organoid research. These electrodes are highly biocompatible and flexible, allowing them to interact seamlessly with neural tissue without causing immune responses or rejection. Their flexibility enables them to adapt to the dynamic growth and structural changes of organoids, ensuring continuous, reliable contact and signal detection over time. Additionally, conductive polymers can conduct both electronic and ionic signals, which better simulate the natural electrochemical environment of neurons. This dual conductivity improves the accuracy of neural signal detection by reducing interference and enhancing the precision of measurements compared to traditional metal electrodes. </sec><sec> The most significant application of these 3D conductive polymer electrodes in brain organoids is their ability to accurately detect neural signals and provide controlled external stimulation. These electrodes are capable of penetrating deep into the organoid’s structure, enabling real-time monitoring of neural activity across multiple layers. This ability is particularly valuable for studying complex neural behaviors, such as abnormal firing patterns in disease models like epilepsy and Parkinson’s disease. The precise, continuous detection of neural signals allows researchers to observe the dynamic activity of neural circuits and synaptic transmission in detail. Beyond signal detection, these electrodes offer the ability to deliver localized electrical stimulation to specific regions of brain organoids. This capability is essential for exploring neural plasticity, circuit modulation, and how external electrical inputs can influence neural networks. Researchers can target particular areas of an organoid to induce specific responses or adjust neural activity to replicate conditions seen in neurological disorders. This dual functionality—simultaneously monitoring and stimulating neural circuits—opens new possibilities for investigating brain function and testing therapeutic strategies in controlled environments. </sec><sec> Looking forward, 3D conductive polymer electrodes hold promise beyond basic research applications. In drug screening, they provide a powerful tool for assessing how new compounds affect neural activity and identifying potential neurotoxic effects in real time. Moreover, these electrodes are showing great potential in the field of brain-computer interface (BCI), where their precision in recording and stimulating neural signals could enable more advanced prosthetics and therapeutic brain implants. As material science and fabrication technologies continue to advance, 3D conductive polymer electrodes are poised to play a transformative role in neuroscience research, offering new insights into brain function and opening new possibilities for the development of treatments for neurological disorders. </sec><sec> This review outlines how the development of 3D conductive polymer micro/nano electrodes has significantly enhanced the capabilities of brain organoid research. Their ability to seamlessly integrate with the organoid structure for precise neural signal detection and stimulation marks a substantial advancement in studying complex brain functions and diseases, as well as drug discovery and potential future applications in BCI. </sec>