In this paper,a polyimide-based flexible device that integrates 16 micro-LEDs and 16 IrO_(x)-modified microelectrodes for synchronous photostimulation and neural signal recording is presented.The 4×4 micro-LEDs(d...In this paper,a polyimide-based flexible device that integrates 16 micro-LEDs and 16 IrO_(x)-modified microelectrodes for synchronous photostimulation and neural signal recording is presented.The 4×4 micro-LEDs(dimensions of 220×270×50μm^(3),700μm pitch)are fixed in the SU-8 fence structure on a polyimide substrate and connected to the leads via a wire-bonding method.The recording electrodes share a similar fabrication process on the polyimide with 16 microelectrode sites(200μm in diameter and 700μm in pitch)modified by iridium oxide(IrO_(x)).These two subparts can be aligned with alignment holes and glued back-to-back by epoxy,which ensures that the light from the LEDs passes through the corresponding holes that are evenly distributed around the recording sites.The long-term electrical and optical stabilities of the device are verified using a soaking test for 3 months,and the thermal property is specifically studied with different duty cycles,voltages,and frequencies.Additionally,the electrochemical results prove the reliability of the IrO_(x)-modified microelectrodes after repeated pressing or friction.To evaluate the tradeoff between flexibility and strength,two microelectrode arrays with thicknesses of 5 and 10μm are evaluated through simulation and experiment.The proposed device can be a useful mapping optogenetics tool for neuroscience studies in small(rats and mice)and large animal subjects and ultimately in nonhuman primates.展开更多
Implantable brain–computer interface(BCI)devices are an effective tool to decipher fundamental brain mechanisms and treat neural diseases.However,traditional neural implants with rigid or bulky cross-sections cause t...Implantable brain–computer interface(BCI)devices are an effective tool to decipher fundamental brain mechanisms and treat neural diseases.However,traditional neural implants with rigid or bulky cross-sections cause trauma and decrease the quality of the neuronal signal.Here,we propose a MEMS-fabricated flexible interface device for BCI applications.The microdevice with a thin film substrate can be readily reduced to submicron scale for low-invasive implantation.An elaborate silicon shuttle with an improved structure is designed to reliably implant the flexible device into brain tissue.The flexible substrate is temporarily bonded to the silicon shuttle by polyethylene glycol.On the flexible substrate,eight electrodes with different diameters are distributed evenly for local field potential and neural spike recording,both of which are modified by Pt-black to enhance the charge storage capacity and reduce the impedance.The mechanical and electrochemical characteristics of this interface were investigated in vitro.In vivo,the small cross-section of the device promises reduced trauma,and the neuronal signals can still be recorded one month after implantation,demonstrating the promise of this kind of flexible BCI device as a low-invasive tool for brain–computer communication.展开更多
The delicate serpentine structures are widely used in high-performance stretchable electronics over the past decade.The metal interconnects encapsulated in biocompatible polymer Parylene-C film is a superior choice fo...The delicate serpentine structures are widely used in high-performance stretchable electronics over the past decade.The metal interconnects encapsulated in biocompatible polymer Parylene-C film is a superior choice for long-term implantation in vivo,especially as neural interface to acquire electrophysiological signals or apply electrical stimulation.To avoid the physical contact damages from the neural tissues such as the brain or peripheral nerves,serpentine interconnects are utilized as stretchable electrodes and usually bonded to the soft elastomer substrate.The adhesion strength between the serpentine interconnects and the elastomer substrate becomes a considerable issue to ensure reliability and structural integrity.In this paper,the stretchable Parylene-C electrodes can be transfer printed onto arbitrary elastomer substrates by a thin layer of silicone rubber adhesive with low modulus for electrocorticogram(ECoG)recording.Mechanical simulation of serpentine structures consisting of same periodic arcs and different straight segments is investigated by uniaxial stretching.Then,the elastic stretchability of serpentine electrodes is further studied by simulation and experiments.After 5000 repetitive stretching cycles,the electrochemical impedance of microelectrodes remains in steady states.These results prove that the silicone rubber adhesive facilitates the interfacial bonding in the structure of stretchable electrodes as the compliant and reliable neural interface.展开更多
基金This work was partially funded by the National Key R&D Program of China under grant 2017YFB1002501the National Natural Science Foundation of China(No.51475307 and 61728402)+3 种基金the Research Program of Shanghai Science and Technology Committee(17JC1402800 and 15JC1400103)the Program of Shanghai Academic/Technology Research Leader(18XD1401900)ZBYY-MOE Joint Funding(6141A02022604)the China Scholarship Council(201606230100).
文摘In this paper,a polyimide-based flexible device that integrates 16 micro-LEDs and 16 IrO_(x)-modified microelectrodes for synchronous photostimulation and neural signal recording is presented.The 4×4 micro-LEDs(dimensions of 220×270×50μm^(3),700μm pitch)are fixed in the SU-8 fence structure on a polyimide substrate and connected to the leads via a wire-bonding method.The recording electrodes share a similar fabrication process on the polyimide with 16 microelectrode sites(200μm in diameter and 700μm in pitch)modified by iridium oxide(IrO_(x)).These two subparts can be aligned with alignment holes and glued back-to-back by epoxy,which ensures that the light from the LEDs passes through the corresponding holes that are evenly distributed around the recording sites.The long-term electrical and optical stabilities of the device are verified using a soaking test for 3 months,and the thermal property is specifically studied with different duty cycles,voltages,and frequencies.Additionally,the electrochemical results prove the reliability of the IrO_(x)-modified microelectrodes after repeated pressing or friction.To evaluate the tradeoff between flexibility and strength,two microelectrode arrays with thicknesses of 5 and 10μm are evaluated through simulation and experiment.The proposed device can be a useful mapping optogenetics tool for neuroscience studies in small(rats and mice)and large animal subjects and ultimately in nonhuman primates.
基金supported by the National Key R&D Program of China under grant 2020YFB1313502the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA25040100,XDA25040200,and XDA25040300)+4 种基金the National Natural Science Foundation of China(No.42127807-03)the Project supported by Shanghai Municipal Science and Technology Major Project(2021SHZDZX)the SJTU Trans-med Award(Nos.2019015,21X010301627)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(Nos.SL2020ZD205,SL2020MS017,SL2103)Scientific Research Fund of Second Institute of Oceanography,MNR(No.SL2020ZD205).
文摘Implantable brain–computer interface(BCI)devices are an effective tool to decipher fundamental brain mechanisms and treat neural diseases.However,traditional neural implants with rigid or bulky cross-sections cause trauma and decrease the quality of the neuronal signal.Here,we propose a MEMS-fabricated flexible interface device for BCI applications.The microdevice with a thin film substrate can be readily reduced to submicron scale for low-invasive implantation.An elaborate silicon shuttle with an improved structure is designed to reliably implant the flexible device into brain tissue.The flexible substrate is temporarily bonded to the silicon shuttle by polyethylene glycol.On the flexible substrate,eight electrodes with different diameters are distributed evenly for local field potential and neural spike recording,both of which are modified by Pt-black to enhance the charge storage capacity and reduce the impedance.The mechanical and electrochemical characteristics of this interface were investigated in vitro.In vivo,the small cross-section of the device promises reduced trauma,and the neuronal signals can still be recorded one month after implantation,demonstrating the promise of this kind of flexible BCI device as a low-invasive tool for brain–computer communication.
基金supported by the National Key R&D Program of China under grant 2017YFB1002501the National Natural Science Foundation of China(No.61728402,No.31600781 and 31972929)+2 种基金Research Program of Shanghai Science and Technology Committee(17JC1402800,17JC1400202 and 19ZR1475000)Program of Shanghai Academic/Technology Research Leader(18XD1401900)Interdisciplinary Program of Shanghai Jiao Tong University(YG2016MS06).
文摘The delicate serpentine structures are widely used in high-performance stretchable electronics over the past decade.The metal interconnects encapsulated in biocompatible polymer Parylene-C film is a superior choice for long-term implantation in vivo,especially as neural interface to acquire electrophysiological signals or apply electrical stimulation.To avoid the physical contact damages from the neural tissues such as the brain or peripheral nerves,serpentine interconnects are utilized as stretchable electrodes and usually bonded to the soft elastomer substrate.The adhesion strength between the serpentine interconnects and the elastomer substrate becomes a considerable issue to ensure reliability and structural integrity.In this paper,the stretchable Parylene-C electrodes can be transfer printed onto arbitrary elastomer substrates by a thin layer of silicone rubber adhesive with low modulus for electrocorticogram(ECoG)recording.Mechanical simulation of serpentine structures consisting of same periodic arcs and different straight segments is investigated by uniaxial stretching.Then,the elastic stretchability of serpentine electrodes is further studied by simulation and experiments.After 5000 repetitive stretching cycles,the electrochemical impedance of microelectrodes remains in steady states.These results prove that the silicone rubber adhesive facilitates the interfacial bonding in the structure of stretchable electrodes as the compliant and reliable neural interface.
