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Ramesh V, Johny J, Jakobi J, Stuckert R, Rehbock C, Barcikowski S. Platinum-Iridium Alloy Nanoparticle Coatings Produced by Electrophoretic Deposition Reduce Impedance in 3D Neural Electrodes. Chemphyschem 2024; 25:e202300623. [PMID: 38842467 DOI: 10.1002/cphc.202300623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 05/14/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024]
Abstract
Platinum-based neural electrodes, frequently alloyed with Ir or W, are routinely used to treat neurological disorders. However, their performance is impaired by an increase in impedance that compromises long-term implant functionality. Though there are multiple coating techniques available to address this issue, electrode, and base material often exhibit a compositional mismatch, which impairs mechanical stability and may lead to toxicological side effects. In this work, we coated Pt wire electrodes with ligand-free electrostatically stabilized colloidal Pt90Ir10, Pt90W10, and Pt50W50 alloy nanoparticles (NPs) matching electrode compositions using electrophoretic deposition (EPD) with direct-current (DC) and pulsed-DC fields in aqueous medium. The generated alloy NPs exhibit a solid solution structure as evidenced by HR-TEM-EDX and XRD, though additional WOx phases were identified in the Pt50W50 samples. Consequently, coating efficiency was also impaired in the presence of high W mass fractions in the alloy NPs. Characterization of the NP coatings by cyclic voltammetry and impedance spectroscopy yielded a significant reduction of the impedance in the Pt90Ir10 sample in comparison to the control coated with Pt NPs. The electrochemical surface area (ECSA) of the PtW alloy coatings, on the other hand, was significantly reduced.
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Affiliation(s)
- Vaijayanthi Ramesh
- Technical Chemistry I, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141, Essen, Germany
| | - Jacob Johny
- Technical Chemistry I, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141, Essen, Germany
| | - Jurij Jakobi
- Technical Chemistry I, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141, Essen, Germany
| | - Robert Stuckert
- Technical Chemistry I, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141, Essen, Germany
| | - Christoph Rehbock
- Technical Chemistry I, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141, Essen, Germany
| | - Stephan Barcikowski
- Technical Chemistry I, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141, Essen, Germany
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Li L, Jiang C, Li L. A Comparative Study on the Effect of Substrate Structure on Electrochemical Performance and Stability of Electrodeposited Platinum and Iridium Oxide Coatings for Neural Electrodes. MICROMACHINES 2023; 15:70. [PMID: 38258189 PMCID: PMC10821385 DOI: 10.3390/mi15010070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/20/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024]
Abstract
Implantable electrodes are crucial for stimulation safety and recording quality of neuronal activity. To enhance their electrochemical performance, electrodeposited nanostructured platinum (nanoPt) and iridium oxide (IrOx) have been proposed due to their advantages of in situ deposition and ease of processing. However, their unstable adhesion has been a challenge in practical applications. This study investigated the electrochemical performance and stability of nanoPt and IrOx coatings on hierarchical platinum-iridium (Pt-Ir) substrates prepared by femtosecond laser, compared with the coatings on smooth Pt-Ir substrates. Ultrasonic testing, agarose gel testing, and cyclic voltammetry (CV) testing were used to evaluate the coatings' stability. Results showed that the hierarchical Pt-Ir substrate significantly enhanced the charge-storage capacity of electrodes with both coatings to more than 330 mC/cm2, which was over 75 times that of the smooth Pt-Ir electrode. The hierarchical substrate could also reduce the cracking of nanoPt coatings after ultrasonic, agarose gel and CV testing. Although some shedding was observed in the IrOx coating on the hierarchical substrate after one hour of sonication, it showed good stability in the agarose gel and CV tests. Stable nanoPt and IrOx coatings may not only improve the electrochemical performance but also benefit the function of neurobiochemical detection.
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Affiliation(s)
- Linze Li
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China
| | - Changqing Jiang
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing 100084, China
| | - Luming Li
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing 100084, China
- IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
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Puglia MK, Bowen PK. Cyclic Voltammetry Study of Noble Metals and Their Alloys for Use in Implantable Electrodes. ACS OMEGA 2022; 7:34200-34212. [PMID: 36188288 PMCID: PMC9520554 DOI: 10.1021/acsomega.2c03563] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Innovation in the application and miniaturization of implantable electrodes has caused a spike in new electrode material research; however, few robust studies are available that compare different metal electrodes in biologically relevant media. Herein, cyclic voltammetry has been employed to compare platinum, palladium, and gold-based electrodes' potentiometric scans and their corresponding charge storage capacities (CSCs). Ten different noble metals and alloys in these families were tested under pseudophysiological conditions in phosphate-buffered saline (pH 7.4) at 37 °C. Charge storage capacity values (mC/cm2) were calculated for the oxide reduction, hydrogen adsorption, hydrogen desorption, and oxide formation peaks. Five scan rates spanning 2 orders of magnitude (10, 50, 100, 500, and 1000 mV/s) in both sparged and aerated environments were evaluated. Materials have been ranked by their charge storage capacities, reversibility, and trends discussed. Palladium-based alloys outperformed platinum-based alloys in the sparged condition and were ranked equally as high in the aerated condition. The Paliney 1100 (Pd-Re) alloy gave the highest observed calculated CSC value of 0.64 ± 0.02 mC/cm2 in the aerated condition, demonstrating 73 ± 5% reversibility. Trends between metal electrode families elicited in this study can afford valuable insight into future engineering of high performing implantable electrode materials.
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Li L, Jiang C, Duan W, Wang Z, Zhang F, He C, Long T, Li L. Electrochemical and biological performance of hierarchical platinum-iridium electrodes structured by a femtosecond laser. MICROSYSTEMS & NANOENGINEERING 2022; 8:96. [PMID: 36065436 PMCID: PMC9440118 DOI: 10.1038/s41378-022-00433-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/20/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Neural electrode interfaces are essential to the stimulation safety and recording quality of various bioelectronic therapies. The recently proposed hierarchical platinum-iridium (Pt-Ir) electrodes produced by femtosecond lasers have exhibited superior electrochemical performance in vitro, but their in vivo performance is still unclear. In this study, we explored the electrochemical performance, biological response, and tissue adhesion of hierarchical Pt-Ir electrodes by implantation in adult rat brains for 1, 8, and 16 weeks. Regular smooth Pt-Ir electrodes were used as a control. The results showed that the electrochemical performance of both electrodes decreased and leveled off during implantation. However, after 16 weeks, the charge storage capacity of hierarchical electrodes stabilized at ~16.8 mC/cm2, which was 15 times that of the smooth control electrodes (1.1 mC/cm2). Moreover, the highly structured electrodes had lower impedance amplitude and cutoff frequency values. The similar histological response to smooth electrodes indicated good biocompatibility of the hierarchically structured Pt-Ir electrodes. Given their superior in vivo performance, the femtosecond laser-treated Pt-Ir electrode showed great potential for neuromodulation applications.
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Affiliation(s)
- Linze Li
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou, 350108 China
| | - Changqing Jiang
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
| | - Wanru Duan
- Department of Neurosurgery, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, 100053 China
- Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, 100053 China
| | - Zhiyan Wang
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
| | - Feng Zhang
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
| | - Changgeng He
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
| | - Tiangang Long
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
| | - Luming Li
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, 100084 China
- Precision Medicine & Healthcare Research Center, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, 518071 China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, 100084 China
- Institute of Epilepsy, Beijing Institute for Brain Disorders, Beijing, 100093 China
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Xiong J, Zhang B, Balilonda A, Yang S, Li K, Zhang Q, Li Y, Wang H, Hou C. Graphene-based implantable neural electrodes for insect flight control. J Mater Chem B 2022; 10:4632-4639. [PMID: 35648073 DOI: 10.1039/d2tb00906d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Implantable neural electrodes have been widely used to investigate the function of the brain and treat neurological disorders. Due to their advantages of size and preparation, fibrous neural electrodes have been widely applied, but conventional metal wire electrodes have many shortcomings that are impossible to overcome. Here, we present a modified graphene-based fiber electrode, which retains the excellent electrical properties of the graphene fiber (GF) electrode and enhances the charge storage capacity (CSC) from the initial 7.97 mC cm-2 to 504.04 mC cm-2. The modified electrodes were further investigated via in vivo experiments, and the results show that the modified graphene fibers controlled insect flight with a minimum voltage close to that of silver wire electrodes, and no irreversible chemical reaction occurred during the electrical stimulation process, which could achieve the stimulation effect while ensuring the safety of the tissues around the electrodes.
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Affiliation(s)
- Jian Xiong
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
| | - Bin Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
| | - Andrew Balilonda
- Research Centre for Smart Wearable Technology, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, P. R. China
| | - Shengyuan Yang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
| | - Kerui Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
| | - Qinghong Zhang
- Engineering Research Center of Advanced Glasses Manufacturing Technology, College of Materials Science and Engineering, Donghua University, 201620, P. R. China
| | - Yaogang Li
- Engineering Research Center of Advanced Glasses Manufacturing Technology, College of Materials Science and Engineering, Donghua University, 201620, P. R. China
| | - Hongzhi Wang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
| | - Chengyi Hou
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
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Zhou N, Ma L. Smart bioelectronics and biomedical devices. Biodes Manuf 2022; 5:1-5. [PMID: 35043079 PMCID: PMC8759059 DOI: 10.1007/s42242-021-00179-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 12/26/2022]
Affiliation(s)
- Nanjia Zhou
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024 China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024 China
| | - Liang Ma
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, 310058 China
- School of Mechanical Engineering, Zhejiang University, Hangzhou, 310058 China
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