A critical challenge lies in the development of the next‐generation neural interface, in mechanically tissue‐compatible fashion, that offer accurate, transient recording electrophysiological (EP) information and autonomous degradation after stable operation. Here, an ultrathin, lightweight, soft and multichannel neural interface is presented based on organic‐electrochemical‐transistor‐(OECT)‐based network, with capabilities of continuous high‐fidelity mapping of neural signals and biosafety active degrading after performing functions. Such platform yields a high spatiotemporal resolution of 1.42 ms and 20 µm, with signal‐to‐noise ratio up to ≈37 dB. The implantable OECT arrays can well establish stable functional neural interfaces, designed as fully biodegradable electronic platforms in vivo. Demonstrated applications of such OECT implants include real‐time monitoring of electrical activities from the cortical surface of rats under various conditions (e.g., narcosis, epileptic seizure, and electric stimuli) and electrocorticography mapping from 100 channels. This technology offers general applicability in neural interfaces, with great potential utility in treatment/diagnosis of neurological disorders.

Organic Electrochemical Transistors This cover demonstrates a bio‐tissue compatible and biodegradable electronics neural interface for efficient monitoring and recording of brain activities. The neural interface features with the formats of ultra‐thin, soft, and conformal mounting on brain, which allows high‐fidelity recording ability. Besides, the biodegradable property appears in the cover as these scattered points around the device, referring to the tiny fragments of the device, as well as the water and carbon dioxide produced during degradation. This biodegradable electronics‐based neural interface suggests an intuitive, facile and efficient methods to a broad audience of researchers in the fields of materials science, microfabrication engineering, mechanical engineering, biomedical engineering, etc. More details can be found in article number 2300504 by Enming Song, Junsheng Yu, Xinge Yu, and co‐workers.

Microsystem technologies for evaluating the mechanical properties of soft biological tissues offer various capabilities relevant to medical research and clinical diagnosis of pathophysiologic conditions. Recent progress includes (1) the development of tissue-compliant designs that provide minimally invasive interfaces to soft, dynamic biological surfaces and (2) improvements in options for assessments of elastic moduli at spatial scales from cellular resolution to macroscopic areas and across depths from superficial levels to deep geometries. This review summarizes a collection of these technologies, with an emphasis on operational principles, fabrication methods, device designs, integration schemes, and measurement features. The core content begins with a discussion of platforms ranging from penetrating filamentary probes and shape-conformal sheets to stretchable arrays of ultrasonic transducers. Subsequent sections examine different techniques based on planar microelectromechanical system (MEMS) approaches for biocompatible interfaces to targets that span scales from individual cells to organs. One highlighted example includes miniature electromechanical devices that allow depth profiling of soft tissue biomechanics across a wide range of thicknesses. The clinical utility of these technologies is in monitoring changes in tissue properties and in targeting/identifying diseased tissues with distinct variations in modulus. The results suggest future opportunities in engineered systems for biomechanical sensing, spanning a broad scope of applications with relevance to many aspects of health care and biology research.

Biosafe wearable healthcare monitor has attracted significant attention owing to their applicability to wearable electronics. However, the narrow sensing range and poor response limit the application of flexible devices for comprehensive monitoring of human health‐related physiological signals (i.e., pulse diagnosis). Critical challenges remain in the development of biocompatible materials and the design of flexible bio‐integrated platforms for these purposes, targeting performance approaching those of conventional wafer‐based technologies and long‐term operational stability. In this context, this work presents a robust and flexible MXene/polydopamine (PDA)‐composite‐film‐based pressure sensor in a portable/wearable fashion, which establishes a unique intercalated spherical‐like PDA molecules structure, thereby resulting in excellent sensing performance. The MXene/PDA‐based pressure sensor has sensitivity of up to 138.8 kPa−1 in the pressure range of 0.18–6.20 kPa with fast response and recovery speed (t1 < 100 ms; t2< 50 ms). Associated embodiment involves real‐time precise measurements of a variety of health‐related physiological signals, ranging from wrist pulse, to finger motions, to vocalization and to facial expressions, with high sensitivity and accuracy. Studies on human subjects establish the clinical significance of these devices for future opportunities of health monitoring and intelligent control to predict and diagnose diseases.

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