Core Viewpoint - The article discusses the development of the world's first three-dimensional (3D) hydrogel semiconductor transistor, which combines the softness and biocompatibility of biological tissues with the precise electronic control of traditional transistors, paving the way for advanced bioelectronic systems [2][3][25]. Group 1: Research Breakthrough - A collaboration between researchers from the University of Hong Kong and the University of Cambridge led to the publication of a paper in Science, detailing the creation of a 3D hydrogel semiconductor transistor [2]. - The new transistor features a modulation thickness of millimeters and possesses biological tissue-level softness and biocompatibility, breaking the barrier between 2D electronic devices and 3D biological systems [3][25]. Group 2: Material Innovation - The research team focused on hydrogels, which are soft and high-water-content materials, traditionally lacking semiconductor properties. Recent advancements in redox-active hydrogels have enabled semiconductor characteristics, but thickness limitations remained a challenge [13]. - The team innovatively designed a dual-network hydrogel system that allows for 3D assembly, ensuring continuous electronic transport while optimizing ionic transport pathways [13][15]. Group 3: Performance Metrics - The 3D hydrogel transistors demonstrated exceptional performance, achieving a switching ratio of approximately 10,000 at a thickness of 1 millimeter, significantly outperforming traditional organic electrochemical transistors (OECT) [20]. - The hydrogel semiconductor's volumetric capacitance maintains a linear relationship with thickness up to millimeters, unlike traditional films that fail to do so beyond approximately 10 micrometers [20]. Group 4: System Applications - The research team successfully created self-supporting fibers from the 3D hydrogel semiconductors, constructing brain-like 3D neuromorphic circuits for data computation and analysis [23]. - In handwritten digit recognition tasks, the system achieved a recognition accuracy of 91.93%, comparable to traditional artificial neural networks, and maintained high predictive accuracy even under 30% strain [23][24]. Group 5: Future Implications - This research signifies a breakthrough in simultaneously controlling the electronic, ionic, and mechanical properties of soft materials at the millimeter scale, potentially leading to a new generation of bio-integrated electronic devices [25]. - The hydrogel semiconductors' biocompatibility and stretchability could establish robust 3D interfaces between electronic devices and biological systems, blurring the lines between technology and life [25].