Many individuals suffer from stroke,osteoarthritis,or accidental hand injuries,making hand rehabilitation greatly significant.The current hand rehabilitation therapy requires repetitive task-oriented hand exercises,re...Many individuals suffer from stroke,osteoarthritis,or accidental hand injuries,making hand rehabilitation greatly significant.The current hand rehabilitation therapy requires repetitive task-oriented hand exercises,relying on exoskeleton mechanical gloves integrated with different sensors and actuators.However,these conventional mechanical gloves require wearing heavy mechanical components that need weightbearing and increase hand burden.Additionally,these devices are usually structurally complex,complicated to operate,and require specialized medical institutions.Here,a Virtual Reality(VR)hand rehabilitation system is developed by integrating deep-learning-assisted electromyography(EMG)recognition and VR human-machine interfaces(HMIs).By applying a wetadhesive,self-healable,and conductive ionic hydrogel electrode array assisted by deep learning,the system can realize 14 Jebsen hand rehabilitation gestures recognition with an accuracy of 97.9%.The recognized gestures further communicate with the VR platform for real-time interaction in a virtual scenario to accomplish VR hand rehabilitation.Compared with present hand rehabilitation devices,the proposed system enables patients to perform immersive hand exercises in real-life scenarios without the need for hand-worn weights,and offers rehabilitation training without time and location limitations.This system could bring great breakthroughs for the development of a load-free hand rehabilitation system available in home-based therapy.展开更多
Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this e...Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this end,in vitro platforms are needed to test therapies directed at salivary(fluid-secreting)cells.However,since these are highly differentiated secretory cells,the maintenance of their differentiated state while expanding in numbers is challenging.In this study,the efficiency of three reversible thermo-ionically crosslinked gels:(1)alginate–gelatin(AG),(2)collagen-containing AG(AGC),and(3)hyaluronic acid-containing AG(AGHA),to recapitulate a native-like environment for human salivary gland(SG)cell expansion and 3D spheroid formation was compared.Although all gels were of mechanical properties comparable to human SG tissue(~11 kPa)and promoted the formation of 3D spheroids,AGHA gels produced larger(>100 cells/spheroid),viable(>93%),proliferative,and well-organized 3D SG spheroids while spatially and temporally maintaining the high expression of key SG proteins(aquaporin-5,NKCC1,ZO-1,α-amylase)for 14 days in culture.Moreover,the spheroids responded to agonist-induced stimulation by increasingα-amylase secretory granules.Here,we propose alternative lowcost,reproducible,and reversible AG-based 3D hydrogels that allow the facile and rapid retrieval of intact,highly viable 3D-SG spheroids.展开更多
Screen sensors are the most commonly used human-machine interfaces in our everyday life,which have been extensively applied in personal electronics like cellphones.Touchless screen sensors are attracting growing inter...Screen sensors are the most commonly used human-machine interfaces in our everyday life,which have been extensively applied in personal electronics like cellphones.Touchless screen sensors are attracting growing interest due to their distinct advantages of high interaction freedom,comfortability,and hand hygiene.However,the material compositions of current touchless screen sensors are rigid and fragile,hardly meeting the needs of wearable and stretchable on-skin electronics development.Additionally,these touchless screen sensors are also restricted by high power consumption,limited gesture types of recognition,and the requirement of light conditions.Here,we report a stretchable on-skin touchless screen sensor(OTSS)enabled by an ionic hydrogel-based triboelectric nanogenerator(TENG).Compared with current touchless screen sensors,the OTSS is stretchable,self-powered,and competent to recognize diverse gestures by making use of charges naturally carried on fingers without the need of sufficient light conditions.An on-skin noncontact screen operating system is further demonstrated on the basis of the OTSS,which could unlock a cellphone interface in touchless operation mode on the human skin.This work for the first time introduces the on-skin touchless concept to screen sensors and offers a direction to develop new-generation screen sensors for future cellphones and personal electronics.展开更多
Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly（Nisopropylacr...Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly（Nisopropylacrylamide）/graphene oxide（PNIPAM/GO） nanocomposite hydrogels with stimuli-responsive bending behaviors are prepared through a simple one-step method by using molds made of a Teflon plate and a glass plate. Residual oxygen in the air bubbles on the Teflon plate surface affects the polymerization and hence the cross-linking density, leading to the different swelling/deswelling rates of the two sides of the gels. Therefore, the hydrogels exhibit bending/unbending behaviors upon heating/cooling in water. The incorporation of GO nanosheets dramatically enhances the mechanical properties of Janus hydrogels. Meanwhile, the photo-responsive property of the GO nanosheets also imparts the hydrogels with remotecontrollable deformation under IR irradiation. The application of the Janus PNIPAM/GO hydrogels as thermo-responsive grippers is demonstrated.展开更多
Ionic hydrogels,owing to the advantages of stretchability,conductivity and transparency,have attracted more attention for developing new soft sensors and artificial skins.Existing works on ionic-hydrogel based sensors...Ionic hydrogels,owing to the advantages of stretchability,conductivity and transparency,have attracted more attention for developing new soft sensors and artificial skins.Existing works on ionic-hydrogel based sensors mostly focus on material synthesis,structure design and functional integration,while few studies investigate the characterization of their sensing performances.In this paper,we present a method to characterize the performance(e.g.,sensitivity,linearity and repeatability)of a kind of ionic-hydrogel based strain sensors by varying the testing frequencies and the sensors’geometry(e.g.,length-width(L/W)ratio).To this end,we first develop an experimental testing platform and fabricate a series of strain sensors made of the polyacrylamide(PAAm)hydrogel containing ionic conductive medium.We establish an equivalent electrical model to represent the ionic-hydrogel based strain sensors,indicating the influence of the testing frequencies and L/W ratio of the ionic hydrogels on their sensing performances.These theoretical predictions are in agreement with results obtained through experimental measurements.We further demonstrate that(1)the sensitivity of the strain sensors,characterized by the gauge factor(GF),increases with the rise of testing frequencies but tends to be stable over the frequency of 5 kHz;(2)the sensitivity GF has a nonlinear relation with the L/W ratio of the strain sensors,but with a certain maximum value under the same testing frequency when the L/W ratio equals to 4.80.We verify the above experimental observations with two commonly used electrolytes,including lithium chloride and sodium chloride.With the optimum testing frequency and L/W ratio,we finally conduct various experiments to demonstrate the low hysteresis and good repeatability of our ionic-hydrogel based strain sensors.This work provides an approach to characterize the performance of the ionic-hydrogel based strain sensors,which may be an important step forward in further applications of ionic hydrogels in soft robotics.展开更多
基金supported by the Scientific and Technological Project in Henan Province(No.242102231002)China Postdoctoral Science Foundation(No.2022M712852).
文摘Many individuals suffer from stroke,osteoarthritis,or accidental hand injuries,making hand rehabilitation greatly significant.The current hand rehabilitation therapy requires repetitive task-oriented hand exercises,relying on exoskeleton mechanical gloves integrated with different sensors and actuators.However,these conventional mechanical gloves require wearing heavy mechanical components that need weightbearing and increase hand burden.Additionally,these devices are usually structurally complex,complicated to operate,and require specialized medical institutions.Here,a Virtual Reality(VR)hand rehabilitation system is developed by integrating deep-learning-assisted electromyography(EMG)recognition and VR human-machine interfaces(HMIs).By applying a wetadhesive,self-healable,and conductive ionic hydrogel electrode array assisted by deep learning,the system can realize 14 Jebsen hand rehabilitation gestures recognition with an accuracy of 97.9%.The recognized gestures further communicate with the VR platform for real-time interaction in a virtual scenario to accomplish VR hand rehabilitation.Compared with present hand rehabilitation devices,the proposed system enables patients to perform immersive hand exercises in real-life scenarios without the need for hand-worn weights,and offers rehabilitation training without time and location limitations.This system could bring great breakthroughs for the development of a load-free hand rehabilitation system available in home-based therapy.
基金support from Fonds de Recherche du Québec Santé(FRQS,grant no.281271)support from FRQS doctoral award #304367funding from CFI,Rheolution Inc.,and Investissement Québec.
文摘Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this end,in vitro platforms are needed to test therapies directed at salivary(fluid-secreting)cells.However,since these are highly differentiated secretory cells,the maintenance of their differentiated state while expanding in numbers is challenging.In this study,the efficiency of three reversible thermo-ionically crosslinked gels:(1)alginate–gelatin(AG),(2)collagen-containing AG(AGC),and(3)hyaluronic acid-containing AG(AGHA),to recapitulate a native-like environment for human salivary gland(SG)cell expansion and 3D spheroid formation was compared.Although all gels were of mechanical properties comparable to human SG tissue(~11 kPa)and promoted the formation of 3D spheroids,AGHA gels produced larger(>100 cells/spheroid),viable(>93%),proliferative,and well-organized 3D SG spheroids while spatially and temporally maintaining the high expression of key SG proteins(aquaporin-5,NKCC1,ZO-1,α-amylase)for 14 days in culture.Moreover,the spheroids responded to agonist-induced stimulation by increasingα-amylase secretory granules.Here,we propose alternative lowcost,reproducible,and reversible AG-based 3D hydrogels that allow the facile and rapid retrieval of intact,highly viable 3D-SG spheroids.
基金supported by the National Natural Science Foundation of China(Nos.62074137,52303112)the Foundation for Outstanding Young Teachers in Universities of Henan Province(No.2021GGJS014)the China Postdoctoral Science Foundation(Nos.2022TQ0281,2023M733213).
文摘Screen sensors are the most commonly used human-machine interfaces in our everyday life,which have been extensively applied in personal electronics like cellphones.Touchless screen sensors are attracting growing interest due to their distinct advantages of high interaction freedom,comfortability,and hand hygiene.However,the material compositions of current touchless screen sensors are rigid and fragile,hardly meeting the needs of wearable and stretchable on-skin electronics development.Additionally,these touchless screen sensors are also restricted by high power consumption,limited gesture types of recognition,and the requirement of light conditions.Here,we report a stretchable on-skin touchless screen sensor(OTSS)enabled by an ionic hydrogel-based triboelectric nanogenerator(TENG).Compared with current touchless screen sensors,the OTSS is stretchable,self-powered,and competent to recognize diverse gestures by making use of charges naturally carried on fingers without the need of sufficient light conditions.An on-skin noncontact screen operating system is further demonstrated on the basis of the OTSS,which could unlock a cellphone interface in touchless operation mode on the human skin.This work for the first time introduces the on-skin touchless concept to screen sensors and offers a direction to develop new-generation screen sensors for future cellphones and personal electronics.
基金financially supported by the National Natural Science Foundation of China(No.21274013)
文摘Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly（Nisopropylacrylamide）/graphene oxide（PNIPAM/GO） nanocomposite hydrogels with stimuli-responsive bending behaviors are prepared through a simple one-step method by using molds made of a Teflon plate and a glass plate. Residual oxygen in the air bubbles on the Teflon plate surface affects the polymerization and hence the cross-linking density, leading to the different swelling/deswelling rates of the two sides of the gels. Therefore, the hydrogels exhibit bending/unbending behaviors upon heating/cooling in water. The incorporation of GO nanosheets dramatically enhances the mechanical properties of Janus hydrogels. Meanwhile, the photo-responsive property of the GO nanosheets also imparts the hydrogels with remotecontrollable deformation under IR irradiation. The application of the Janus PNIPAM/GO hydrogels as thermo-responsive grippers is demonstrated.
基金supported by the National Natural Science Foundation of China(Grant Nos.9184820451622506 and 91948302)the Shanghai Jiao Tong University Scientific and Technological Innovation Funds。
文摘Ionic hydrogels,owing to the advantages of stretchability,conductivity and transparency,have attracted more attention for developing new soft sensors and artificial skins.Existing works on ionic-hydrogel based sensors mostly focus on material synthesis,structure design and functional integration,while few studies investigate the characterization of their sensing performances.In this paper,we present a method to characterize the performance(e.g.,sensitivity,linearity and repeatability)of a kind of ionic-hydrogel based strain sensors by varying the testing frequencies and the sensors’geometry(e.g.,length-width(L/W)ratio).To this end,we first develop an experimental testing platform and fabricate a series of strain sensors made of the polyacrylamide(PAAm)hydrogel containing ionic conductive medium.We establish an equivalent electrical model to represent the ionic-hydrogel based strain sensors,indicating the influence of the testing frequencies and L/W ratio of the ionic hydrogels on their sensing performances.These theoretical predictions are in agreement with results obtained through experimental measurements.We further demonstrate that(1)the sensitivity of the strain sensors,characterized by the gauge factor(GF),increases with the rise of testing frequencies but tends to be stable over the frequency of 5 kHz;(2)the sensitivity GF has a nonlinear relation with the L/W ratio of the strain sensors,but with a certain maximum value under the same testing frequency when the L/W ratio equals to 4.80.We verify the above experimental observations with two commonly used electrolytes,including lithium chloride and sodium chloride.With the optimum testing frequency and L/W ratio,we finally conduct various experiments to demonstrate the low hysteresis and good repeatability of our ionic-hydrogel based strain sensors.This work provides an approach to characterize the performance of the ionic-hydrogel based strain sensors,which may be an important step forward in further applications of ionic hydrogels in soft robotics.
