Traditional polysomnography (PSG) systems are limited by cumbersome hardware, inefficient clinical workflows, and significant patient discomfort, hindering accurate characterization of natural sleep. Here, we present a wearable sleep-breathing monitoring system based on a printed electronic skin (E-skin) sensor that enables comfortable, high-fidelity, and home-viable respiratory assessment. The device employs a resistive eutectic gallium-indium-tin (EGaInSn) liquid-metal sensing layer screen-printed onto a flexible thermoplastic polyurethane (TPU) substrate, offering stable sensitivity over a broad dynamic range, mechanical robustness, and seamless skin conformability for long-term wear. A six-channel sensing network was implemented to capture thoracic and abdominal respiratory dynamics across diverse sleeping positions. Comprehensive clinical validation was conducted against gold-standard PSG, with respiratory events independently scored by Registered Polysomnographic Technologists (RPSGTs) under single-blind conditions. The system demonstrates high concordance with PSG in identifying obstructive and central sleep apnea, hypopnea, Cheyne–Stokes respiration, and respiratory rate abnormalities. By integrating flexible electronics and clinically aligned signal interpretation, this work advances wearable health technologies from conventional physiological monitoring toward credible diagnostic capability, providing a practical solution for continuous, accurate evaluation of sleep-related breathing disorders.

For biointegrated flexible systems that acquire and process electrophysiological signals, amplifying weak biosignals from their original low amplitudes (ranging from microvolt to millivolt) to volt-level is essential for subsequent processing. Achieving this level of amplification requires a high voltage gain (>105 or 100 decibels for microvolt signals). However, realizing such gain in flexible circuits remains highly challenging because of constrained integration scale and limits in feasible circuit topologies. Here, we report flexible amplifiers that achieve ultrahigh gain by leveraging intrinsic gain singularities induced by negative differential resistance (NDR) effect in carbon nanotube–based transistors. The NDR behavior is investigated under various factors, including contacts, gate structures, and channel lengths. Guided by insights into the correlations between NDR characteristics and device-level parameters, a device-circuit codesign approach is implemented to build a flexible amplifier achieving a record-high gain of 104 decibels among all reported flexible amplifiers, with successful demonstration of electroencephalogram signals amplification. A carbon nanotube–based flexible amplifier achieves >100-dB voltage gain, demonstrating EEG signal amplification.

Transistor-integrated flexible pressure sensors have received considerable interest in emerging fields such as humanoid robotics, prosthetics, and implantable electronics. However, existing designs for these integrated sensors often exhibit a trade-off between pressure response and operating voltage, thus significantly limiting their practical applications. In this letter, we report a unique device design of integrated pressure sensors based on deformable microstructured electrodes capacitively coupled with floating-gate carbon nanotube transistors. The microstructured electrodes can dramatically enhance the pressure-introduced electrostatic control of the transistor, enabling a substantial improvement in the transduced pressure response at low operating voltages. With this unique design, we achieve a high pressure response of $10^5$ and an ultrahigh sensitivity up to $10^4 \text kPa^\text - 1$ at a low operating voltage below 3 V, which holds great promise for the development of advanced functionalized flexible electronics.