Publications by authors named "Longchun Wang"

6 Publications

  • Page 1 of 1

Self-adaptive cardiac optogenetics device based on negative stretching-resistive strain sensor.

Sci Adv 2021 Nov 24;7(48):eabj4273. Epub 2021 Nov 24.

National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China.

[Figure: see text].
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http://dx.doi.org/10.1126/sciadv.abj4273DOI Listing
November 2021

Dense Packed Drivable Optrode Array for Precise Optical Stimulation and Neural Recording in Multiple-Brain Regions.

ACS Sens 2021 Nov 15;6(11):4126-4135. Epub 2021 Nov 15.

National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China.

The input-output function of neural networks is complicated due to the huge number of neurons and synapses, and some high-density implantable electrophysiology recording tools with a plane structure have been developed for neural circuit studies in recent years. However, traditional plane probes are limited by the record-only function and inability to monitor multiple-brain regions simultaneously, and the complete cognition of neural networks still has a long way away. Herein, we develop a three-dimensional (3D) high-density drivable optrode array for multiple-brain recording and precise optical stimulation simultaneously. The optrode array contains four-layer probes with 1024 microelectrodes and two thinned optical fibers assembled into a 3D-printed drivable module. The recording performance of microelectrodes is optimized by electrochemical modification, and precise implantation depth control of drivable optrodes is verified in agar. Moreover, in vivo experiments indicate neural activities from CA1 and dentate gyrus regions are monitored, and a tracking of the neuron firing for 2 weeks is achieved. The suppression of neuron firing by blue light has been realized through high-density optrodes during optogenetics experiments. With the feature of large-scale recording, optoelectronic integration, and 3D assembly, the high-density drivable optrode array possesses an important value in the research of brain diseases and neural networks.
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http://dx.doi.org/10.1021/acssensors.1c01650DOI Listing
November 2021

Fabrication and Characterization of Iridium Oxide pH Microelectrodes Based on Sputter Deposition Method.

Sensors (Basel) 2021 Jul 23;21(15). Epub 2021 Jul 23.

National Key Laboratory of Science and Technology on Micro/Nano Fabrication Laboratory, Collaborative Innovation Center of IFSA, Department of Micro/Nano-Electronics, Shanghai Jiao Tong University, Shanghai 200240, China.

pH value plays an important role in many fields such as chemistry and biology; therefore, rapid and accurate pH measurement is very important. Because of its advantages in preparation, wide test range, rapid response, and good biocompatibility, iridium oxide material has received more and more attention. In this paper, we present a method for preparing iridium oxide pH microelectrodes based on the sputter deposition method. The sputtering parameters of iridium oxide are also studied and optimized. Open-circuit potential tests show that microelectrodes exhibit near-Nernstian pH response with good linearity (about 60 mV/pH), fast response, high stability (a slight periodic fluctuation of potential change <2.5 mV in 24 h), and good reversibility in the pH range of 1.00-13.00.
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http://dx.doi.org/10.3390/s21154996DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8348779PMC
July 2021

An artefact-resist optrode with internal shielding structure for low-noise neural modulation.

J Neural Eng 2020 08 5;17(4):046024. Epub 2020 Aug 5.

National Key Laboratory of Science and Technology on Micro/Nano Fabrication Laboratory, Key Laboratory for Thin Film and Micro fabrication of the Ministry of Education, Collaborative Innovation Center of IFSA, Department of Micro/Nano-electronics, Shanghai Jiao Tong University, Shanghai, People's Republic of China.

Objective: The combination of optical manipulation of neural activities with electrophysiology recording is a promising technology for discovering mechanisms of brain disorders and mapping brain networks. However, fiber-based optrode is limited by the large size of light source and the winding of optical fiber, which hinders animal's natural movement. Meanwhile, the laser diode (LD)-based optrode restricted to the stimulation-locked artefacts will contaminate neural signal acquired from recording channels.

Approach: Here, a reformative low-noise optrode with internal grounded shielding layer is proposed to mitigate the stimulus-locked artefacts generated during LDactivation for the application of optogenetics.

Main Results: The artefact mitigation capacity of grounded shielding was verified via simulation and experiments with transient amplitude of artefacts declined from over 5 mV to approximately 200 µV in-vitro. Meanwhile, the stimulation parameters were used based on previous studies by which neurons were activated without over heating the tissue as characterized by in-vitro studies (the output optical intensity is 823 ± 38 mW mm). Furthermore, the microelectrodes were modified with Poly (3, 4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT: PSS) to increase the signal recording quality of the optrode. Finally, in-vivo optogenetics experiments were carried in the hippocampus of one mouse and the results showed our low-noise optrode was qualified to achieve high-quality neural recording (signal-to-noise ratio about 13) and specific neuron stimulation simultaneously.

Significance: These results suggest the low-noise optrodes exhibit the ability of manipulating and recording neural dynamics and they are excellent candidates for neuroscience research.
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http://dx.doi.org/10.1088/1741-2552/aba41fDOI Listing
August 2020

Flexible and stretchable opto-electric neural interface for low-noise electrocorticogram recordings and neuromodulation in vivo.

Biosens Bioelectron 2020 Apr 9;153:112009. Epub 2020 Jan 9.

National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address:

Optogenetic-based neuromodulation tools is evolving for the basic neuroscience research in animals combining optical manipulation and electrophysiological recordings. However, current opto-electric integrated devices attaching on cerebral cortex for electrocorticogram (ECoG) still exist potential damage risks for both brain tissue and electrode, due to the mechanical mismatch and brain deformation. Here, we propose a stretchable opto-electric integrated neural interface by integrating serpentine-shaped electrodes and multisite micro-LEDs onto a hyperelastic substrate, as well as a serpentine-shaped metal shielding embedded in recording electrode for low-noise signal acquisition. The delicate structure design, ultrasoft encapsulation and independent fabrication followed by assembly are beneficial to the conformality, reliability and yield. In vitro accelerated deterioration and reciprocating tensile have demonstrated good performance and high stability. In vivo optogenetic activation of focal cortical areas of awaked mouse expressing Channelrhodopsin-2 is realized with simultaneous high-quality recording. We highlight the potential use of this multifunctional neural interface for neural applications.
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http://dx.doi.org/10.1016/j.bios.2020.112009DOI Listing
April 2020

Flexible bioelectrodes with enhanced wrinkle microstructures for reliable electrochemical modification and neuromodulation in vivo.

Biosens Bioelectron 2019 Jun 17;135:181-191. Epub 2019 Apr 17.

National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address:

Limited electrode size with high electrochemical performance and reliability of modified materials are two of the main concerns for flexible neural electrodes in recent years. Here, an effective fabrication method of enhanced micro-scale wrinkles based on oil-pretreated hyperelastic substrates (PDMS and Ecoflex) is proposed for the application of microelectrode biosensors. Compared to pre-stretching or compressing methods, this approach has better advantages including compatibility with MEMS processes on wafer and easy replication. Wrinkled gold microelectrodes exhibit superior electrochemical properties than the flat one, and no crack or delamination occurs after electroplating PEDOT:PSS and platinum black on wrinkled microelectrodes. Cyclic voltammetry (CV) scanning for 2500 times is performed to investigate adhesion and stability of modified materials. For the modified microelectrodes, no significant change is observed in charge storage capacity (CSC) and impedance at 1 kHz, whereas PEDOT:PSS coated flat microelectrodes appears delamination. Ultrasonication and cycling forces are also conducted on modified microelectrodes, which demonstrates little influence on the wrinkled ones. Flexible wrinkled microelectrodes are further verified by in-vivo ECoG recordings combined with optogenetics in mice. These results highlight the importance of micro-structure in neural electrode design and tremendous application potentials in flexible electronics.
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http://dx.doi.org/10.1016/j.bios.2019.04.025DOI Listing
June 2019
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