A Highly Sensitive Coaxial Nanofiber Mask for Respiratory Monitoring Assisted with Machine Learning

Respiration is a critical physiological process of the body and plays an essential role in maintaining human health.Wearable piezoelectric nanofiber-based respiratory monitoring has attracted much attention due to its self-power,high linearity,noninvasiveness,and convenience.However,the limited sensitivity of conventional piezoelectric nanofibers makes it difficult to meet medical and daily respiratory monitoring requirements due to their low electromechanical conversion efficiency.Here,we present a universally applicable,highly sensitive piezoelectric nanofiber characterized by a coaxial composite structure of polyvinylidene fluoride(PVDF)and carbon nanotube(CNT),which is denoted as PS-CC.Based on elucidating the enhancement mechanism from the percolation effect,PS-CC exhibits excellent sensing performance with a high sensitivity of 3.7 V/N and a fast response time of 20 ms for electromechanical conversion.As a proof-of-concept,the nanofiber membrane is seamlessly integrated into a facial mask,facilitating accurate recognition of respiratory states.With the assistance of a one-dimensional convolutional neural network(CNN),a PS-CC-based smart mask can recognize respiratory tracts and multiple breathing patterns with a classification accuracy of up to 97.8%.Notably,this work provides an effective strategy for monitoring respiratory diseases and offers widespread utility for daily health monitoring and clinical applications.

Miniaturized retractable thin-film sensor for wearable multifunctional respiratory monitoring

As extremely important physiological indicators,respiratory signals can often reflect or predict the depth and urgency of various diseases.However,designing a wearable respiratory monitoring system with convenience,excellent durability,and high precision is still an urgent challenge.Here,we designed an easy-fabricate,lightweight,and badge reel-like retractable selfpowered sensor(RSPS)with high precision,sensitivity,and durability for continuous detection of important indicators such as respiratory rate,apnea,and respiratory ventilation.By using three groups of interdigital electrode structures with phase differences,combined with flexible printed circuit boards(FPCBs)processing technology,a miniature rotating thin-film triboelectric nanogenerator(RTF-TENG)was developed.Based on discrete sensing technology,the RSPS has a sensing resolution of 0.13 mm,sensitivity of 7 P·mm^(−1),and durability more than 1 million stretching cycles,with low hysteresis and excellent anti-environmental interference ability.Additionally,to demonstrate its wearability,real-time,and convenience of respiratory monitoring,a multifunctional wearable respiratory monitoring system(MWRMS)was designed.The MWRMS demonstrated in this study is expected to provide a new and practical strategy and technology for daily human respiratory monitoring and clinical diagnosis.

Multiple Respiratory Gas Monitoring Causes Changes of Inspired oxygen Concentration in Closed Anesthesia System

Effect of multiple respiratory gas monitoring (MRGM ) on inspiredconcentration of oxygen in circult system during closed anesthesia was studied in 5l adult patients scheduled for abdominal surgery. Required flow rate of fresh oxygen (OFR), inspired oxygen concentration (FiO2 ) and oxygen saturation of pulse oximeter (SpO2) were measured continu0usly. Patients were equally divided into three groups at randorn, group C (no MRGN used ), group M, (using MRGM with its tail gas returned to circuit system), group M2 (using MRGM without tail gas returned ). The results revealed that during 180 min of closed anesthesia, OFR required in group C and M, were about 200-230 ml/min, and in group M, it was ab0ut 400 ml/min. In group C FiO2 decreased by about 10 % after 60 min of closed anesthesia (P<0. 01, 60 min vs 0 min ) and then stayed stable at this level. In group M,, FiO2 decreased by 16% at 60 min and 34 % at 180 min and the decrease was significantly greater than that in gr0up C (P<0. 01). In group Me, FiO2 remained c0nstant during closed anesthesia, which was much high(Jr than those in group C and M,. The tail gas of Capnomac Ultima MRGM contained less oxygen than its sample gas drawn fr0m circuit system simuItaneously.

Anti-fatigue ionic gels for long-term multimodal respiratory abnormality monitoring

Wearable electronics integrated with stretchable sensors are considered a promising and non-invasive strategy to monitor respiratory status for health assessment.However,long-term and stable monitoring of respiratory abnormality is still a grand challenge.Here,we report a facile one-step thermal stretching strategy to fabricate an anti-fatigue ionic gel(AIG)sensor with high fatigue threshold(0=1130 J m^(–2)),high stability(>20,000 cycles),high linear sensitivity,and recyclability.A multimodal wearable respiratory monitoring system(WRMS)developed with AIG sensors can continuously measure respiratory abnormality(single-sensor mode)and compliance(multi-sensor mode)by monitoring the movement of the ribcage and abdomen in a long-term manner.For single-sensor mode,the respiratory frequency(Fr),respiratory energy(Er),and inspire/expire time(I/E ratio)can be extracted to evaluate the respiratory status during sitting,sporting,and sleeping.Further,the multi-sensors mode is developed to evaluate patientventilator asynchrony through validated clinical criteria by monitoring the incongruous movement of the chest and abdomen,which shows great potential for both daily home care and clinical applications.

Water Molecule-Triggered Anisotropic Deformation of Carbon Nitride Nanoribbons Enabling Contactless Respiratory Inspection

The exploitation of the interaction between nanostructured matter and small molecules,such as H_(2)O at interfaces via dynamic hydrogen bonding,is essentially the key for smart,responsive nanodevices but remains challenging.Herein,the authors report that the carbon nitride nanoribbons(CNNRs)with an anisotropic intraplanar and interplanar molecular arrangement underwent a deformation by H_(2)O triggering.Both experiments of bulk samples and single nanoribbons disclosed that the reversible formation of a hydrogen-bonded H_(2)O adsorption layer was the source of the CNNRs deformation,reminiscent of the hydration-triggered twist of natural bean pods in seeding.Nonetheless,CNNRs had a more balanced H_(2)O affinity,enabling a superior response and recovery time.By coupling with carbon nanotubes,the authors also converted the deformation of CNNRs into more straightforward electrical readouts with record-fast response time.Further applied to capture fluctuations in humidity in real-time respiration,a higher detection sensitivity was obtained in a contactless mode,which compared favorably with the clinical breath-testing station.Given the carbon nitride family with various C/N ratios,surface properties,and topography,this finding that CNNRs are an outstanding H_(2)O transducer would significantly pave the way for the H_(2)O-triggered smart devices in broad prospective applications.

Superhydrophobic MXene‑Based Fabric with Electromagnetic Interference Shielding and Thermal Management Ability for Flexible Sensors

Smart fabrics have made remarkable progress in the field of wearable electronics because of their unique structure,flexibility and breathability,which are highly desirable with integrated multifunctionality.Here,a superhydrophobic smart fabric has been fabricated by decorating conductive MXene on nylon fabric modified by polydopamine(PDA),followed by spraying hydrophobic materials(SiO_(2) and FOTS).The hydrophobic layer not only provides the fabric with superhydrophobicity,but also protects MXene from oxidation.Highly conductive MXene-wrapped fibers endow the fabric with adjustable conductivity and many satisfactory functions.Commendably,the smart fabric possesses sensing performances of ultralow detection limit(0.2%strain),fast response time(60 ms),short recovery time(90 ms),and outstanding sensing stability(5000 cycles).These sensing performances allow the smart fabric to accurately detect body respiratory signals in the running state,exercise state and sleep state,thus keeping track of respiratory health information.Moreover,the smart fabric also exhibits outstanding EMI shielding effectiveness(66.5 dB)in the X-band,satisfactory photothermal performance(68.6℃at 100 mW/cm2),and excellent electrothermal conversion capability(up to 102.3℃at 8 V).Therefore,the smart fabric is extremely promising for applications in EMI shielding,thermal management,and respiratory monitoring,and is an ideal candidate for smart clothing and as a medical diagnostic tool.

Recent progress of diversiform humidity sensors based on versatile nanomaterials and their prospective applications

Humidity sensors are of significance in various fields,such as environmental and food quality monitoring,industrial processing,wearable and flexible electronics,and human health care.High-performance humidity sensors with high sensitivity,rapid response time,and good stability are of paramount importance in humidity sensing.In this paper,diversiform humidity sensors with different sensing mechanisms are summarized,including resistive,impedance,capacitive,quartz crystal microbalance(QCM),surface acoustic wave(SAW),field-effect transistor(FET),and optical fiber humidity sensors.Versatile nanomaterials such as graphene,transition-metal chalcogenide,MXenes,black phosphorus(BP),boron nitride(BN),polymers,and nanofibers were promising building-blocks for constructing humidity sensors.The latest progress in the wearable and flexible humidity sensors,and self-powered humidity sensors was summarized.The diversiform applications of the humidity sensors with great prospects were demonstrated in various fields in terms of human respiratory monitoring,skin dryness diagnosing,fingertip approaching,and non-contact switch.Moreover,the challenges and prospects of nanomaterials-based humidity sensors were discussed.

Ultra-thin CoAl layered double hydroxide nanosheets for the construction of highly sensitive and selective QCM humidity sensor

To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics of CoAl LDH were investigated by transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectric spectroscopy(XPS),Brunauer–Emmett–Telle(BET),atomic force microscopy(AFM)and zeta potential.Due to their large specific surface area and abundant hydroxyl groups,CoAl LDH nanosheets exhibit good humidity sensing performance.In a range of 11.3%and 97.6%relative humidity(RH),the sensor behaved an ultrahigh sensitivity(127.8 Hz/%RH),fast response(9.1 s)and recovery time(3.1 s),low hysteresis(3.1%RH),good linearity(R^(2)=0.9993),stability and selectivity.Besides,the sensor can recover the initial response frequency after being wetted by deionized water,revealing superior self-recovery ability under high humidity.Based on in-situ Fourier transform infrared spectroscopy(FT-IR),the adsorption mechanism of CoAl LDH toward water molecules was explored.The QCM sensor can distinguish different respiratory states of people and wetting degree of fingers,as well as monitor the humidity in vegetable packaging,suggesting excellent properties and a promising application in humidity sensing.