Guihua Xiao1, Yilin Song1, Song Zhang1, Lili Yang1, Shengwei Xu1, Yu Zhang1, Huiren Xu1, Fei Gao1, Ziyue Li1, Xinxia Cai2. 1. State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 10090, China. 2. State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 10090, China. Electronic address: xxcai@mail.ie.ac.cn.
Abstract
BACKGROUND: Hippocampus is a critical part of brain tissue involved in many cognitive neural activities. They are controlled by various neurotransmitters such as glutamate (Glu), and affected by electrophysiology. NEW METHOD: Herein, we fabricated a 16-site (25μm in diameter) microelectrode array (MEA) biosensor applied in dual-mode tests including Glu and neural spike measurements. METHODS: All the 16 recording sites were electrodeposited with platinum nanoparticles (PtNPs) and 8 sites were used for electrical recording. Glutamate oxidase enzyme (Gluox) and 1,3-Phenylenediamine (mPD) layer were specially modified on the other 8 sites for Glu recording. The dual-mode MEA was implanted from cortex to hippocampus of anesthetized rat to record Glu content and firing rate. RESULTS: The electrical sites showed much lower impedance. The Glu sites showed much higher sensitivity(7.807 pA/μM), and ideal selectivity to the major molecules in brain. The post calibration sensitivity (3.935 pA/μM) maintained on a positive level. Different Glu content peaks including cortex (18.32μM) and hippocampal CA1 (4.39μM), CA3 (10.16μM), dentate gyrus (DG, two layers: 5.36μM and 10.34μM) have detected. The corresponded firing rate was recorded, too. COMPARISON WITH EXISTING METHODS: This modification showed much lower impedance and much higher sensitivity. We obtained more neuron activities simultaneously by dual-mode recording. The covariation of Glu and neural spike signals was discovered in the specific hippocampus sub-region. CONCLUSIONS: The covariation between Glu and firing rate changes were synchronous, and effected by regions. The dual-mode signals were useful to find the neurology disease mechanism.
BACKGROUND: Hippocampus is a critical part of brain tissue involved in many cognitive neural activities. They are controlled by various neurotransmitters such as glutamate (Glu), and affected by electrophysiology. NEW METHOD: Herein, we fabricated a 16-site (25μm in diameter) microelectrode array (MEA) biosensor applied in dual-mode tests including Glu and neural spike measurements. METHODS: All the 16 recording sites were electrodeposited with platinum nanoparticles (PtNPs) and 8 sites were used for electrical recording. Glutamate oxidase enzyme (Gluox) and 1,3-Phenylenediamine (mPD) layer were specially modified on the other 8 sites for Glu recording. The dual-mode MEA was implanted from cortex to hippocampus of anesthetized rat to record Glu content and firing rate. RESULTS: The electrical sites showed much lower impedance. The Glu sites showed much higher sensitivity(7.807 pA/μM), and ideal selectivity to the major molecules in brain. The post calibration sensitivity (3.935 pA/μM) maintained on a positive level. Different Glu content peaks including cortex (18.32μM) and hippocampal CA1 (4.39μM), CA3 (10.16μM), dentate gyrus (DG, two layers: 5.36μM and 10.34μM) have detected. The corresponded firing rate was recorded, too. COMPARISON WITH EXISTING METHODS: This modification showed much lower impedance and much higher sensitivity. We obtained more neuron activities simultaneously by dual-mode recording. The covariation of Glu and neural spike signals was discovered in the specific hippocampus sub-region. CONCLUSIONS: The covariation between Glu and firing rate changes were synchronous, and effected by regions. The dual-mode signals were useful to find the neurology disease mechanism.