From smart contact lenses to e-tattoos, learn how cutting-edge materials and state-of-the-art sensors are revolutionizing wearable technology, enhancing health monitoring, and transforming human-machine interactions.

A person wearing a black shirt interacts with a smartwatch on their wrist, touching its screen with their other hand.

For so many of us, wearable devices have changed the game for health monitoring and better understanding our bodies, providing comprehensive data on sleep, activity, heart rate, and much more. Wearables are becoming increasingly ubiquitous in society, from the smartwatch to virtual reality glasses, skin patches, and smart garments. In the introductory editorial for a recent Chemical Reviews Virtual Thematic Issue, Xiaodong Chen and colleagues reveal that the global wearable technology market was worth over $55 billion in 2022 and is predicted to grow to at least $142 billion by 2030.1

But as the field becomes more mainstream, we continually expect more from the tech, with demand for devices that are thinner, smaller, softer, and more stretchable to establish more reliable contact with our skin—ensuring accurate biosignal collection and feedback stimulation. Wearable device research inherently spans multiple disciplines and research domains; recognizing the broad scope of this field, this Virtual Thematic Issue brings together researchers and experts from diverse backgrounds to discuss recent advancements, trends, and future directions for wearable devices. Below, we’ve summarized a few of the latest trends and hot topics—to access all of the in-depth review articles, be sure to check out the complete collection of articles.

Next-Gen Materials

The future of wearables is being shaped by groundbreaking advancements in materials science that aim to revolutionize the way we think about and use wearable devices, offering new levels of functionality, integration, and user comfort.

One exciting development is the emergence of transient electronic systems, a technology that can dissolve, disintegrate, or otherwise disappear at controlled rates after fulfilling their purpose. These systems, particularly bioresorbable electronics, are designed to be inserted into the human body, providing sensing and therapeutic functions in harmony with natural biological processes. After their operational period, these devices safely dissolve, eliminating the need for secondary removal surgeries and reducing patient risk. The advancements in materials chemistry are crucial here, spanning organic, inorganic, and hybrid compounds that react predictably in biological environments.

Meanwhile, gallium-based liquid metals (LM) are paving the way for conformal bioelectronics, thanks to their high conductivity and biocompatibility. When combined with polymers, these liquid metal–polymer conductors (MPC) create a flexible and versatile platform for developing cyborg devices that conform to the body's contours. These MPC-based devices are used for sensing various biological signals, performing therapeutic interventions, and enhancing bodily functions. The synthesis and fabrication techniques of these materials are crucial in bridging the gap between their creation and their biomedical applications, showcasing their potential in next-gen wearable devices.

Additionally, the field of flexible electronics is rapidly advancing, driven by the unique properties of two-dimensional (2D) materials. These materials are ideal for flexible electronic applications and can be integrated into a variety of surfaces or manipulated into different forms. The scalable production and innovative fabrication processes of 2D materials have led to significant breakthroughs, enabling the development of flexible devices that can be seamlessly incorporated into wearable tech. This includes everything from sensors to energy-efficient components, all designed to enhance the functionality and comfort of wearable devices.

A Second Skin: Getting Creative with Form

Wearable technology is evolving beyond conventional designs, aiming to integrate seamlessly with the human body. This shift is driven by advancements in materials and form factors that promise to revolutionize healthcare, human-machine interactions, and beyond.

One of the most promising developments in this area is e-tattoos. These ultrathin, skin-soft wearable electronics can noninvasively and accurately digitize physiological and psychological information from the human body without compromising comfort or mobility. Unlike traditional rigid electronics, e-tattoos conform to the skin, making them nearly imperceptible. They can perform a wide range of functions, including sensing, wound healing, and energy harvesting. This innovation promises to revolutionize telemedicine, mobile health, and human-machine interactions.

In parallel, smart contact lenses are transforming ocular health management and disease monitoring. Smart contact lenses can diagnose and manage ophthalmic, metabolic, and neurological diseases by tracking biomarkers in the eye. The integration of sensors and wireless communication within these lenses enables continuous health monitoring, offering a noninvasive, comfortable solution for patients. Challenges include improving user acceptance and integrating with existing healthcare systems, but the potential impact on eye care is significant.

Wireless, battery-free implantable organ interfaces represent another groundbreaking advancement. These devices use soft materials, miniaturized electronics, and sensors to create systems that match the mechanical properties of target organs. Eliminating electrochemical power storage, they provide high-fidelity physiological readings and enable precise organ control. This innovation supports personalized digital medicine and new therapeutic paradigms, promising more effective and less invasive medical interventions.

State-of-the-Art Sensors

Innovations in wearable sensor technology are driving significant advancements in how we monitor and interact with our bodies. For example, wearable electrochemical glucose sensors have transformed diabetes management by providing real-time tracking of glucose levels. Since the 1960s, these sensors have evolved significantly, now utilizing alternative body fluids to offer pain-free, noninvasive, or minimally invasive monitoring. This review highlights the mechanisms of electrochemical glucose sensing, the progression of these sensors over time, and the development of multiplexed wearable sensors for optimal diabetes management. The commercial landscape is expanding with continuous glucose monitors and emerging technologies aimed at personalized diabetes management, potentially leading to an autonomous closed-loop artificial pancreas.

Wearable sweat sensors are also making strides in personalized health monitoring by leveraging advances in flexible electronics, materials science, and electrochemistry. These sensors continuously and noninvasively monitor health indicators through sweat, addressing challenges such as sweat extraction, sensing capabilities, and device comfort. By improving these aspects and understanding the clinical value of sweat analytes, these sensors can empower precision medicine. Design considerations for prolonged sweat extraction, efficient powering, and system-level development are crucial for their success in health monitoring.

Haptic human–machine interfaces (HHMIs) are enhancing how we interact with machines and robots by combining tactile sensation with haptic feedback. Recent advancements in soft sensors and actuators have improved the accuracy, softness, and reliability of these interfaces. Material and structural innovations enable effective sensing and feedback properties, essential for applications in the metaverse, robotics, and interactive devices. HHMIs are set to provide immersive experiences and more intuitive control, transforming various industries and everyday life.

Explore More Expert Insights on Wearable Technology

These innovations promise to revolutionize healthcare, enhance human-machine interactions, and provide new levels of user comfort and functionality. To read about these exciting developments in greater detail and discover more cutting-edge research in the field, be sure to read the full Virtual Thematic Issue in Chemical Reviews.

Chemical Reviews Journal Cover
Virtual Thematic Issue

Wearable Devices

This Virtual Thematic Issue brings together leaders in the field of diverse backgrounds to discuss recent advancements, trends, and future directions for wearable devices.

Want the latest stories delivered to your inbox each month?