Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stab...Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.展开更多
Accurate quantification of exercise interventions and changes in muscle function is essential for personalized health management.Electrical impedance myography(EIM)technology offers an innovative,noninvasive,painless,...Accurate quantification of exercise interventions and changes in muscle function is essential for personalized health management.Electrical impedance myography(EIM)technology offers an innovative,noninvasive,painless,and easy-to-perform solution for muscle health monitoring.However,current EIM platforms face a number of limitations,including large device size,wired connections,and instability of the electrode-skin interface,which limit their applicability for monitoring mus-cle movement.In this study,a miniature wireless EIM platform with a user-friendly smartphone app is proposed and devel-oped.The miniature,wireless,multi-frequency(20 kHz-1 MHz)EIM platform is equipped with flexible microneedle array elec-trodes(MAE).The advantages of MAEs over conventional electrodes were demonstrated by physical field modeling simula-tions and skin-electrode contact impedance comparison tests.The smartphone APP was developed to wirelessly operate the EIM platform,and to transmit and process real-time muscle impedance data.To validate its effectiveness,a seven-day adaptive fatigue training study was conducted,which demonstrated that the EIM platform was able to detect muscle adaptations and serve as a reliable indicator of fatigue.This study presents an innovative approach to applying EIM technology to muscle health monitoring and exercise testing,thereby advancing the development of personalized health management and athletic performance assessment.展开更多
Microneedle array(MNA)electrodes are an effective solution to achieve high-quality surface biopotential recording without the coordination of conductive gel and are thus very suitable for long-term wearable applicatio...Microneedle array(MNA)electrodes are an effective solution to achieve high-quality surface biopotential recording without the coordination of conductive gel and are thus very suitable for long-term wearable applications.Existing schemes are limited by flexibility,biosafety,and manufacturing costs,which create large barriers for wider applications.Here,we present a novel flexible MNA electrode that can simultaneously achieve flexibility of the substrate to fit a curved body surface,robustness of microneedles to penetrate the skin without fracture,and a simplified process to allow mass production.The compatibility with wearable wireless systems and the short preparation time of the electrodes significantly improves the comfort and convenience of electrophysiological recording.The normalized electrode–skin contact impedance reaches 0.98 kΩcm^(2)at 1 kHz and 1.50 kΩcm^(2)at 10 Hz,a record low value compared to previous reports and approximately 1/250 of the standard electrodes.The morphology,biosafety,and electrical/mechanical properties are fully characterized,and wearable recordings with a high signal-to-noise ratio and low motion artifacts are realized.The first reported clinical study of microneedle electrodes for surface electrophysiological monitoring was conducted in tens of healthy and sleep-disordered subjects with 44 nights of recording(over 8 h per night),providing substantial evidence that the electrodes can be leveraged to substitute for clinical standard electrodes.展开更多
Monitoring multiplexed biochemical markers is beneficial for the comprehensive evaluation of diabetes-associated complications.Techniques for multiplexed analyses in interstitial fluids have often been restricted by t...Monitoring multiplexed biochemical markers is beneficial for the comprehensive evaluation of diabetes-associated complications.Techniques for multiplexed analyses in interstitial fluids have often been restricted by the difficulties of electrode materials in accurately detecting chemicals in complex subcutaneous spaces.In particular,the signal stability of enzyme-based sensing electrodes often inevitably decreases due to enzyme degradation or interference in vivo.In this study,we developed a self-calibrating multiplexed microneedle(MN)electrode array(SC-MMNEA)capable of continuous,real-time monitoring of multiple types of bioanalytes(glucose,cholesterol,uric acid,lactate,reactive oxygen species[ROSs],Na+,K+,Ca2+,and pH)in the subcutaneous space.Each type of analyte was detected by a discrete MN electrode assembled in an integrated array with single-MN resolution.Moreover,this device utilized an MN-delivery-mediated self-calibration technique to address the inherent problem of decreased accuracy of implantable electrodes caused by long-term tissue variation and enzyme degradation,and this technique might increase the reliability of the MN sensors.Our results indicated that SC-MMNEA could provide real-time monitoring of multiplexed analyte concentrations in a rat model with good accuracy,especially after self-calibration.SC-MMNEA has the advantages of in situ and minimally invasive monitoring of physiological states and the potential to promote wearable devices for long-term monitoring of chemical species in vivo.展开更多
Ionogels have enabled flexible electronic devices for wide-ranging innovative applications in wearable electronics,soft robotics,and intelligent systems.Ionogels for flexible electronics need to essentially tolerate s...Ionogels have enabled flexible electronic devices for wide-ranging innovative applications in wearable electronics,soft robotics,and intelligent systems.Ionogels for flexible electronics need to essentially tolerate stress,temperature,humidity,and solvents that may cause their electrical conductivity,structural stability,processing compatibility and sensibility failure.Herein,we developed a novel in-situ photopolymerization protocol to fabricate intrinsically conductive,self-gated ionogels via ion-restriction dual effects.Highly sensitive and intelligent safety sensors with tunable stretchability,robust chemical stability,favorable printability,and complete recyclability,are programmed from defined microneedle arrays printed by the intrinsically conductive ionogel.Ultrahigh elasticity(~794%elongation),high compression tolerance(~90%deformation),improved mechanical strength(tensile and compressive strength of~2.0 MPa and~16.3 MPa,respectively)and remark-able transparency(>91.1%transmittance),as well as high-temperature sensitivity(-2.07%℃^(-1))and a wide working range(-40 to200℃)can be achieved.In particular,the intrinsic sensing mechanisms of ion-restriction dual effects are unlocked based on DFT calculations and MD simulations,and operando temperature-dependent FTIR,and Raman technolo-gies.Moreover,the real-time intelligent monitoring systems toward physical signals and precise temperature based on the microneedle array-structures sensors are also presented and demonstrate great potential applications for extreme environ-ments,e.g.,fire,deep-sea or aerospace.展开更多
This paper describes a theoretical estimation of the geometry of negative epoxy-resist microneedles prepared via inclined/rotated ultraviolet(UV)lithography based on spatially controlled UV exposure doses.In compariso...This paper describes a theoretical estimation of the geometry of negative epoxy-resist microneedles prepared via inclined/rotated ultraviolet(UV)lithography based on spatially controlled UV exposure doses.In comparison with other methods based on UV lithography,the present method can create microneedle structures with high scalability.When negative photoresist is exposed to inclined/rotated UV through circular mask patterns,a three-dimensional,needle-shaped distribution of the exposure dose forms in the irradiated region.Controlling the inclination angles and the exposure dose modifies the photo-polymerized portion of the photoresist,thus allowing the variation of the heights and contours of microneedles formed by using the same mask patterns.In an experimental study,the dimensions of the fabricated needles agreed well with the theoretical predictions for varying inclination angles and exposure doses.These results demonstrate that our theoretical approach can provide a simple route for fabricating microneedles with on-demand geometry.The fabricated microneedles can be used as solid microneedles or as a mold master for dissolving microneedles,thus simplifying the microneedle fabrication process.We envision that this method can improve fabrication accuracy and reduce fabrication cost and time,thereby facilitating the practical applications of microneedle-based drug delivery technology.展开更多
基金supported in part by the National Natural Science Foundation of China(Grant No.62104056)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21F010010)+4 种基金the National Natural Science Foundation of China(Grant Nos.62141409 and 62204204)the National Key R&D Program of China(Grant No.2022ZD0208602)the Zhejiang Provincial Key Research&Development Fund(Grant Nos.2019C04003 and 2021C01041)the Shanghai Sailing Program(Grant No.21YF1451000)the Key Research and Development Program of Shaanxi(Grant No.2022GY-001).
文摘Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.
文摘Accurate quantification of exercise interventions and changes in muscle function is essential for personalized health management.Electrical impedance myography(EIM)technology offers an innovative,noninvasive,painless,and easy-to-perform solution for muscle health monitoring.However,current EIM platforms face a number of limitations,including large device size,wired connections,and instability of the electrode-skin interface,which limit their applicability for monitoring mus-cle movement.In this study,a miniature wireless EIM platform with a user-friendly smartphone app is proposed and devel-oped.The miniature,wireless,multi-frequency(20 kHz-1 MHz)EIM platform is equipped with flexible microneedle array elec-trodes(MAE).The advantages of MAEs over conventional electrodes were demonstrated by physical field modeling simula-tions and skin-electrode contact impedance comparison tests.The smartphone APP was developed to wirelessly operate the EIM platform,and to transmit and process real-time muscle impedance data.To validate its effectiveness,a seven-day adaptive fatigue training study was conducted,which demonstrated that the EIM platform was able to detect muscle adaptations and serve as a reliable indicator of fatigue.This study presents an innovative approach to applying EIM technology to muscle health monitoring and exercise testing,thereby advancing the development of personalized health management and athletic performance assessment.
基金supported by the China Capital Health Research and Development of Special (No. 2018-14111)the National Natural Science Foundation of China (grant No. 62004007 and No. 82027805)the China Postdoctoral Science Foundation Grant (No. 2021M700258)
文摘Microneedle array(MNA)electrodes are an effective solution to achieve high-quality surface biopotential recording without the coordination of conductive gel and are thus very suitable for long-term wearable applications.Existing schemes are limited by flexibility,biosafety,and manufacturing costs,which create large barriers for wider applications.Here,we present a novel flexible MNA electrode that can simultaneously achieve flexibility of the substrate to fit a curved body surface,robustness of microneedles to penetrate the skin without fracture,and a simplified process to allow mass production.The compatibility with wearable wireless systems and the short preparation time of the electrodes significantly improves the comfort and convenience of electrophysiological recording.The normalized electrode–skin contact impedance reaches 0.98 kΩcm^(2)at 1 kHz and 1.50 kΩcm^(2)at 10 Hz,a record low value compared to previous reports and approximately 1/250 of the standard electrodes.The morphology,biosafety,and electrical/mechanical properties are fully characterized,and wearable recordings with a high signal-to-noise ratio and low motion artifacts are realized.The first reported clinical study of microneedle electrodes for surface electrophysiological monitoring was conducted in tens of healthy and sleep-disordered subjects with 44 nights of recording(over 8 h per night),providing substantial evidence that the electrodes can be leveraged to substitute for clinical standard electrodes.
基金support from the National Natural Sci-ence Foundation of China(grant nos.T2225010,32171399,and 32171456)Guangdong Basic and Applied Basic Research Foundation(grant no.2023A1515011267)+1 种基金Science and Technalogy Program of Guangzhou,China(grant nos.2024B03J0121 and 2024B03J1284)the Independent Fund of the State Key Laboratory of Optoelectronic Ma-terials and Technologies(Sun YatSen University)under grant no.
文摘Monitoring multiplexed biochemical markers is beneficial for the comprehensive evaluation of diabetes-associated complications.Techniques for multiplexed analyses in interstitial fluids have often been restricted by the difficulties of electrode materials in accurately detecting chemicals in complex subcutaneous spaces.In particular,the signal stability of enzyme-based sensing electrodes often inevitably decreases due to enzyme degradation or interference in vivo.In this study,we developed a self-calibrating multiplexed microneedle(MN)electrode array(SC-MMNEA)capable of continuous,real-time monitoring of multiple types of bioanalytes(glucose,cholesterol,uric acid,lactate,reactive oxygen species[ROSs],Na+,K+,Ca2+,and pH)in the subcutaneous space.Each type of analyte was detected by a discrete MN electrode assembled in an integrated array with single-MN resolution.Moreover,this device utilized an MN-delivery-mediated self-calibration technique to address the inherent problem of decreased accuracy of implantable electrodes caused by long-term tissue variation and enzyme degradation,and this technique might increase the reliability of the MN sensors.Our results indicated that SC-MMNEA could provide real-time monitoring of multiplexed analyte concentrations in a rat model with good accuracy,especially after self-calibration.SC-MMNEA has the advantages of in situ and minimally invasive monitoring of physiological states and the potential to promote wearable devices for long-term monitoring of chemical species in vivo.
基金supported by the National Key R&D Program of China(2020YFA0709900)the National Natural Science Foundation of China(22175167)the National Key R&D Program of the MOST of China(Grant No.2022YFA1602601).
文摘Ionogels have enabled flexible electronic devices for wide-ranging innovative applications in wearable electronics,soft robotics,and intelligent systems.Ionogels for flexible electronics need to essentially tolerate stress,temperature,humidity,and solvents that may cause their electrical conductivity,structural stability,processing compatibility and sensibility failure.Herein,we developed a novel in-situ photopolymerization protocol to fabricate intrinsically conductive,self-gated ionogels via ion-restriction dual effects.Highly sensitive and intelligent safety sensors with tunable stretchability,robust chemical stability,favorable printability,and complete recyclability,are programmed from defined microneedle arrays printed by the intrinsically conductive ionogel.Ultrahigh elasticity(~794%elongation),high compression tolerance(~90%deformation),improved mechanical strength(tensile and compressive strength of~2.0 MPa and~16.3 MPa,respectively)and remark-able transparency(>91.1%transmittance),as well as high-temperature sensitivity(-2.07%℃^(-1))and a wide working range(-40 to200℃)can be achieved.In particular,the intrinsic sensing mechanisms of ion-restriction dual effects are unlocked based on DFT calculations and MD simulations,and operando temperature-dependent FTIR,and Raman technolo-gies.Moreover,the real-time intelligent monitoring systems toward physical signals and precise temperature based on the microneedle array-structures sensors are also presented and demonstrate great potential applications for extreme environ-ments,e.g.,fire,deep-sea or aerospace.
基金This work was partially supported by Japan Science Technology Agency,Izumi Science and Technology Foundation,the Tateisi Science and Technology Foundation,and the Mazda Foundation
文摘This paper describes a theoretical estimation of the geometry of negative epoxy-resist microneedles prepared via inclined/rotated ultraviolet(UV)lithography based on spatially controlled UV exposure doses.In comparison with other methods based on UV lithography,the present method can create microneedle structures with high scalability.When negative photoresist is exposed to inclined/rotated UV through circular mask patterns,a three-dimensional,needle-shaped distribution of the exposure dose forms in the irradiated region.Controlling the inclination angles and the exposure dose modifies the photo-polymerized portion of the photoresist,thus allowing the variation of the heights and contours of microneedles formed by using the same mask patterns.In an experimental study,the dimensions of the fabricated needles agreed well with the theoretical predictions for varying inclination angles and exposure doses.These results demonstrate that our theoretical approach can provide a simple route for fabricating microneedles with on-demand geometry.The fabricated microneedles can be used as solid microneedles or as a mold master for dissolving microneedles,thus simplifying the microneedle fabrication process.We envision that this method can improve fabrication accuracy and reduce fabrication cost and time,thereby facilitating the practical applications of microneedle-based drug delivery technology.
