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Trueman RP, Guillemot-Legris O, Lancashire HT, Mehta AS, Tropp J, Daso RE, Rivnay J, Tabor AB, Phillips JB, Schroeder BC. Aligned Bioelectronic Polypyrrole/Collagen Constructs for Peripheral Nerve Interfacing. ADVANCED ENGINEERING MATERIALS 2024; 26:2301488. [PMID: 39100393 PMCID: PMC11296654 DOI: 10.1002/adem.202301488] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Indexed: 08/06/2024]
Abstract
Electrical stimulation has shown promise in clinical studies to treat nerve injuries. This work is aimed to create an aligned bioelectronic construct that can be used to bridge a nerve gap, directly interfacing with the damaged nerve tissue to provide growth support. The conductive three-dimensional bioelectronic scaffolds described herein are composite materials, comprised of conductive polypyrrole (PPy) nanoparticles embedded in an aligned collagen hydrogel. The bioelectronic constructs are seeded with dorsal root ganglion derived primary rat neurons and electrically stimulated in vitro. The PPy loaded constructs support a 1.7-fold increase in neurite length in comparison to control collagen constructs. Furthermore, upon electrical stimulation of the PPy-collagen construct, a 1.8-fold increase in neurite length is shown. This work illustrates the potential of bioelectronic constructs in neural tissue engineering and lays the groundwork for the development of novel bioelectronic materials for neural interfacing applications.
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Affiliation(s)
- Ryan P. Trueman
- UCL Centre for Nerve Engineering, University College London, London WC1N 1AX, UK; Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, UK
| | - Owein Guillemot-Legris
- UCL Centre for Nerve Engineering, University College London, London WC1N 1AX, UK, Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, UK
| | - Henry T. Lancashire
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Abijeet S. Mehta
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Joshua Tropp
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Rachel E. Daso
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Alethea B. Tabor
- Department of Chemistry, University College London, London WC1H 0AJ, UK
| | - James B. Phillips
- UCL Centre for Nerve Engineering, University College London, London WC1N 1AX, UK, Department of Pharmacology, UCL School of Pharmacy, University College London, London WC1N 1AX, UK
| | - Bob C. Schroeder
- Department of Chemistry, University College London, London WC1H 0AJ, UK
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Matta R, Moreau D, O’Connor R. Printable devices for neurotechnology. Front Neurosci 2024; 18:1332827. [PMID: 38440397 PMCID: PMC10909977 DOI: 10.3389/fnins.2024.1332827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/01/2024] [Indexed: 03/06/2024] Open
Abstract
Printable electronics for neurotechnology is a rapidly emerging field that leverages various printing techniques to fabricate electronic devices, offering advantages in rapid prototyping, scalability, and cost-effectiveness. These devices have promising applications in neurobiology, enabling the recording of neuronal signals and controlled drug delivery. This review provides an overview of printing techniques, materials used in neural device fabrication, and their applications. The printing techniques discussed include inkjet, screen printing, flexographic printing, 3D printing, and more. Each method has its unique advantages and challenges, ranging from precise printing and high resolution to material compatibility and scalability. Selecting the right materials for printable devices is crucial, considering factors like biocompatibility, flexibility, electrical properties, and durability. Conductive materials such as metallic nanoparticles and conducting polymers are commonly used in neurotechnology. Dielectric materials, like polyimide and polycaprolactone, play a vital role in device fabrication. Applications of printable devices in neurotechnology encompass various neuroprobes, electrocorticography arrays, and microelectrode arrays. These devices offer flexibility, biocompatibility, and scalability, making them cost-effective and suitable for preclinical research. However, several challenges need to be addressed, including biocompatibility, precision, electrical performance, long-term stability, and regulatory hurdles. This review highlights the potential of printable electronics in advancing our understanding of the brain and treating neurological disorders while emphasizing the importance of overcoming these challenges.
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Affiliation(s)
- Rita Matta
- Mines Saint-Etienne, Centre CMP, Departement BEL, Gardanne, France
| | - David Moreau
- Mines Saint-Etienne, Centre CMP, Departement BEL, Gardanne, France
| | - Rodney O’Connor
- Mines Saint-Etienne, Centre CMP, Departement BEL, Gardanne, France
- Department of Chemical Engineering, Polytechnique Montreal, Montreal, QC, Canada
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3
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Rapier CE, Jagadeesan S, Vatine G, Ben-Yoav H. Microfluidic channel sensory system for electro-addressing cell location, determining confluency, and quantifying a general number of cells. Sci Rep 2022; 12:3248. [PMID: 35228609 PMCID: PMC8885753 DOI: 10.1038/s41598-022-07194-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 02/14/2022] [Indexed: 01/01/2023] Open
Abstract
Microfluidics is a highly useful platform for culturing, monitoring, and testing biological cells. The integration of electrodes into microfluidic channels extends the functionality, sensing, and testing capabilities of microfluidic systems. By employing an electrochemical impedance spectroscopy (EIS) technique, the non-invasive, label-free detection of the activities of cells in real-time can be achieved. To address the movement toward spatially resolving cells in cell culture, we developed a sensory system capable of electro-addressing cell location within a microfluidic channel. This simple system allows for real-time cell location, integrity monitoring (of barrier producing cells), and confluency sensing without the need for frequent optical evaluation-saving time. EIS results demonstrate that cells within microfluidic channels can be located between various pairs of electrodes at different positions along the length of the device. Impedance spectra clearly differentiates between empty, sparse, and confluent microfluidic channels. The system also senses the level of cell confluence between electrode pairs-allowing for the relative quantification of cells in different areas of the microfluidic channel. The system's electrode layout can easily be incorporated into other devices. Namely, organ-on-a-chip devices, that require the monitoring of precise cell location and confluency levels for understanding tissue function, modeling diseases, and for testing therapeutics.
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Affiliation(s)
- Crystal E Rapier
- Nanobioelectronics Laboratory (NBEL), Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Srikanth Jagadeesan
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, The Regenerative Medicine and Stem Cell (RMSC) Research Center, The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Gad Vatine
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, The Regenerative Medicine and Stem Cell (RMSC) Research Center, The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel.
| | - Hadar Ben-Yoav
- Nanobioelectronics Laboratory (NBEL), Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel.
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Dorovskikh SI, Vikulova ES, Korolkov IV, Maksimovskiy EA, Kal’nyi DB, Morozova NB. MICROSTRUCTURE OF IRIDIUM ENRICHED PtxIr(1–x) FILMS PREPARED BY CHEMICAL VAPOR DEPOSITION. J STRUCT CHEM+ 2021. [DOI: 10.1134/s0022476621090146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Hejazi M, Tong W, Ibbotson MR, Prawer S, Garrett DJ. Advances in Carbon-Based Microfiber Electrodes for Neural Interfacing. Front Neurosci 2021; 15:658703. [PMID: 33912007 PMCID: PMC8072048 DOI: 10.3389/fnins.2021.658703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Neural interfacing devices using penetrating microelectrode arrays have emerged as an important tool in both neuroscience research and medical applications. These implantable microelectrode arrays enable communication between man-made devices and the nervous system by detecting and/or evoking neuronal activities. Recent years have seen rapid development of electrodes fabricated using flexible, ultrathin carbon-based microfibers. Compared to electrodes fabricated using rigid materials and larger cross-sections, these microfiber electrodes have been shown to reduce foreign body responses after implantation, with improved signal-to-noise ratio for neural recording and enhanced resolution for neural stimulation. Here, we review recent progress of carbon-based microfiber electrodes in terms of material composition and fabrication technology. The remaining challenges and future directions for development of these arrays will also be discussed. Overall, these microfiber electrodes are expected to improve the longevity and reliability of neural interfacing devices.
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Affiliation(s)
- Maryam Hejazi
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - Wei Tong
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - David J. Garrett
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- School of Engineering, RMIT University, Melbourne, VIC, Australia
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6
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Reliability of Neural Implants-Effective Method for Cleaning and Surface Preparation of Ceramics. MICROMACHINES 2021; 12:mi12020209. [PMID: 33669493 PMCID: PMC7922903 DOI: 10.3390/mi12020209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 02/06/2023]
Abstract
Neural implants provide effective treatment and diagnosis options for diseases where pharmaceutical therapies are missing or ineffective. These active implantable medical devices (AIMDs) are designed to remain implanted and functional over decades. A key factor for achieving reliability and longevity are cleaning procedures used during manufacturing to prevent failures associated with contaminations. The Implantable Devices Group (IDG) at University College London (UCL) pioneered an approach which involved a cocktail of reagents described as “Leslie’s soup”. This process proved to be successful but no extensive evaluation of this method and the cocktail’s ingredients have been reported so far. Our study addressed this gap by a comprehensive analysis of the efficacy of this cleaning method. Surface analysis techniques complemented adhesion strengths methods to identify residues of contaminants like welding flux, solder residues or grease during typical assembly processes. Quantitative data prove the suitability of “Leslie’s soup” for cleaning of ceramic components during active implant assembly when residual ionic contaminations were removed by further treatment with isopropanol and deionised water. Solder and flux contaminations were removed without further mechanical cleaning. The adhesive strength of screen-printed metalisation layers increased from 12.50 ± 3.83 MPa without initial cleaning to 21.71 ± 1.85 MPa. We conclude that cleaning procedures during manufacturing of AIMDs, especially the understanding of applicability and limitations, is of central importance for their reliable and longevity.
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Volatile Iridium and Platinum MOCVD Precursors: Chemistry, Thermal Properties, Materials and Prospects for Their Application in Medicine. COATINGS 2021. [DOI: 10.3390/coatings11010078] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Interest in iridium and platinum has been steadily encouraged due to such unique properties as exceptional chemical inertia and corrosion resistance, high biological compatibility, and mechanical strength, which are the basis for their application in medical practice. Metal-organic chemical vapor deposition (MOCVD) is a promising method to fabricate Ir and Pt nanomaterials, multilayers, and heterostructures. Its advantages include precise control of the material composition and microstructure in deposition processes at relatively low temperatures onto non-planar substrates. The development of MOCVD processes is inextricably linked with the development of the chemistry of volatile precursors, viz., specially designed coordination and organometallic compounds. This review describes the synthesis methods of various iridium and platinum precursors, their thermal properties, and examples of the use of MOCVD, including formation of films for medical application and bimetallics. Although metal acetylacetonates are currently the most widely used precursors, the recently developed heteroligand Ir(I) and Pt(IV) complexes appear to be more promising in both synthetic and thermochemical aspects. Their main advantage is their ability to control thermal properties by modifying several types of ligands, making them tunable to deposit films onto different types of materials and to select a combination of compatible compounds for obtaining the bimetallic materials.
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8
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Eickenscheidt M, Langenmair M, Dbouk A, Nötzel D, Hanemann T, Stieglitz T. 3D-Printed Hermetic Alumina Housings. MATERIALS (BASEL, SWITZERLAND) 2021; 14:E200. [PMID: 33401644 PMCID: PMC7795362 DOI: 10.3390/ma14010200] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 01/26/2023]
Abstract
Ceramics are repeatedly investigated as packaging materials because of their gas tightness, e.g., as hermetic implantable housing. Recent advances also make it possible to print the established aluminum oxide in a Fused Filament Fabrication process, creating new possibilities for manufacturing personalized devices with complex shapes. This study was able to achieve integration of channels with a diameter of 500 µm (pre-sintered) with a nozzle size of 250 µm (layer thickness 100 µm) and even closed hemispheres were printed without support structures. During sintering, the weight-bearing feedstock shrinks by 16.7%, resulting in a relative material density of 96.6%. The well-known challenges of the technology such as surface roughness (Ra = 15-20 µm) and integrated cavities remain. However, it could be shown that the hollow structures in bulk do not represent a mechanical weak point and that the material can be gas-tight (<10-12 mbar s-1). For verification, a volume-free helium leak test device was developed and validated. Finally, platinum coatings with high adhesion examined the functionalization of the ceramic. All the prerequisites for hermetic housings with integrated metal structures are given, with a new level of complexity of ceramic shapes available.
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Affiliation(s)
- Max Eickenscheidt
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110 Freiburg, Germany; (M.L.); (A.D.); (T.S.)
| | - Michael Langenmair
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110 Freiburg, Germany; (M.L.); (A.D.); (T.S.)
| | - Ahmad Dbouk
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110 Freiburg, Germany; (M.L.); (A.D.); (T.S.)
| | - Dorit Nötzel
- Institute for Applied Materials, Karlsruhe Institute of Technology, 76344 Karlsruhe, Germany; (D.N.); (T.H.)
| | - Thomas Hanemann
- Institute for Applied Materials, Karlsruhe Institute of Technology, 76344 Karlsruhe, Germany; (D.N.); (T.H.)
- Laboratory for Materials Process Technology, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110 Freiburg, Germany
| | - Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110 Freiburg, Germany; (M.L.); (A.D.); (T.S.)
- Bernstein Center Freiburg, University of Freiburg, 79104 Freiburg, Germany
- Brain-Links Brain-Tools, University of Freiburg, 79110 Freiburg, Germany
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9
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Abend A, Steele C, Schmidt S, Frank R, Jahnke HG, Zink M. Proliferation and Cluster Analysis of Neurons and Glial Cell Organization on Nanocolumnar TiN Sub-Strates. Int J Mol Sci 2020; 21:E6249. [PMID: 32872379 PMCID: PMC7503702 DOI: 10.3390/ijms21176249] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022] Open
Abstract
Biomaterials employed for neural stimulation, as well as brain/machine interfaces, offer great perspectives to combat neurodegenerative diseases, while application of lab-on-a-chip devices such as multielectrode arrays is a promising alternative to assess neural function in vitro. For bioelectronic monitoring, nanostructured microelectrodes are required, which exhibit an increased surface area where the detection sensitivity is not reduced by the self-impedance of the electrode. In our study, we investigated the interaction of neurons (SH-SY5Y) and glial cells (U-87 MG) with nanocolumnar titanium nitride (TiN) electrode materials in comparison to TiN with larger surface grains, gold, and indium tin oxide (ITO) substrates. Glial cells showed an enhanced proliferation on TiN materials; however, these cells spread evenly distributed over all the substrate surfaces. By contrast, neurons proliferated fastest on nanocolumnar TiN and formed large cell agglomerations. We implemented a radial autocorrelation function of cellular positions combined with various clustering algorithms. These combined analyses allowed us to quantify the largest cluster on nanocolumnar TiN; however, on ITO and gold, neurons spread more homogeneously across the substrates. As SH-SY5Y cells tend to grow in clusters under physiologic conditions, our study proves nanocolumnar TiN as a potential bioactive material candidate for the application of microelectrodes in contact with neurons. To this end, the employed K-means clustering algorithm together with radial autocorrelation analysis is a valuable tool to quantify cell-surface interaction and cell organization to evaluate biomaterials' performance in vitro.
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Affiliation(s)
- Alice Abend
- Soft Matter Physics Division and Biotechnology & Biomedical Group, Peter-Debye-Institute for Soft Matter Physics, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany; (A.A.); (C.S.)
| | - Chelsie Steele
- Soft Matter Physics Division and Biotechnology & Biomedical Group, Peter-Debye-Institute for Soft Matter Physics, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany; (A.A.); (C.S.)
| | - Sabine Schmidt
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, 04103 Leipzig, Germany; (S.S.); (R.F.)
| | - Ronny Frank
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, 04103 Leipzig, Germany; (S.S.); (R.F.)
| | - Heinz-Georg Jahnke
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, 04103 Leipzig, Germany; (S.S.); (R.F.)
| | - Mareike Zink
- Soft Matter Physics Division and Biotechnology & Biomedical Group, Peter-Debye-Institute for Soft Matter Physics, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany; (A.A.); (C.S.)
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10
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Zeng Q, Zhao S, Yang H, Zhang Y, Wu T. Micro/Nano Technologies for High-Density Retinal Implant. MICROMACHINES 2019; 10:E419. [PMID: 31234507 PMCID: PMC6630275 DOI: 10.3390/mi10060419] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/14/2019] [Accepted: 06/21/2019] [Indexed: 01/10/2023]
Abstract
During the past decades, there have been leaps in the development of micro/nano retinal implant technologies, which is one of the emerging applications in neural interfaces to restore vision. However, higher feedthroughs within a limited space are needed for more complex electronic systems and precise neural modulations. Active implantable medical electronics are required to have good electrical and mechanical properties, such as being small, light, and biocompatible, and with low power consumption and minimal immunological reactions during long-term implantation. For this purpose, high-density implantable packaging and flexible microelectrode arrays (fMEAs) as well as high-performance coating materials for retinal stimulation are crucial to achieve high resolution. In this review, we mainly focus on the considerations of the high-feedthrough encapsulation of implantable biomedical components to prolong working life, and fMEAs for different implant sites to deliver electrical stimulation to targeted retinal neuron cells. In addition, the functional electrode materials to achieve superior stimulation efficiency are also reviewed. The existing challenge and future research directions of micro/nano technologies for retinal implant are briefly discussed at the end of the review.
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Affiliation(s)
- Qi Zeng
- Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China.
| | - Saisai Zhao
- Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China.
| | - Hangao Yang
- Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China.
| | - Yi Zhang
- Shenzhen CAS-Envision Medical Technology Co. Ltd., Shenzhen 518100, China.
| | - Tianzhun Wu
- Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China.
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11
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Mohapatra A, Wells C, Jennings A, Ghimire M, Mishra SR, Morshed BI. Electric Stimulus-Responsive Chitosan/MNP Composite Microbeads for a Drug Delivery System. IEEE Trans Biomed Eng 2019; 67:226-233. [PMID: 30998454 DOI: 10.1109/tbme.2019.2911579] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the last several years, conventional drug delivery systems (DDS) have evolved into DDS that are responsive to exogenous or endogenous stimuli. The objective of this paper is to present a DDS that is responsive to an electric stimulus in the form of bipolar electric pulses. The DDS structure is based on chitosan embedded with magnetic nanoparticles, and crosslinked with polyethylene glycol dimethacrylate to form microbeads. This DDS is loaded with vancomycin as the therapeutic agent of interest. Silver inter-digitated electrodes (IDE) were printed on polyimide substrates with a MEMS-based inkjet material deposition printer, and used to provide 100 Hz pulses of electric current to the DDS for 3 min. The results showed that the stimulated groups released ∼800% more vancomycin than the non-stimulated groups in the excitation duration, but followed a first-order elution profile otherwise. Another significance of our approach is that it does not need complicated or expensive fabrication processes, and can be customized according to the targeted implant site. The IDE system has also been modeled using COMSOL to study the distributed electric fields and ion migration during the stimulus. This paper demonstrates a novel and promising technique of providing stimulus to drug substrates for controllable drug delivery.
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Kundu A, Nattoo C, Fremgen S, Springer S, Ausaf T, Rajaraman S. Optimization of makerspace microfabrication techniques and materials for the realization of planar, 3D printed microelectrode arrays in under four days. RSC Adv 2019; 9:8949-8963. [PMID: 35517709 PMCID: PMC9062012 DOI: 10.1039/c8ra09116a] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 03/11/2019] [Indexed: 12/24/2022] Open
Abstract
Conventional two-dimensional microelectrode arrays (2D MEAs) in the market involve long manufacturing timeframes, have cleanroom requirements, and need to be assembled from multiple parts to obtain the final packaged device. For MEAs to be “used and tossed”, manufacturing has to be moved from the cleanroom to makerspaces. In order to enable makerspace fabricated MEAs comparable to conventional MEAs, the microfabrication processes must be optimized to have similar electrical properties along with biocompatibility and number of recording sites. This work presents a makerspace microfabricated 2D MEA having electrode densities up to a commercially popular 8 × 8 array, all fabricated under four days. Additive manufacturing-based realization of the MEA devices provides immense flexibility in terms of meeting distinct design requirements. A unique non-planar MEA having meso-scale electrodes on the top side of a chip transitioning to traces onto the bottom side through electrical vias is presented in this work. This allows for (a) monolithic integration of a culture well for devices having up to a 6 × 6 MEA array, (b) selective electroplating of the meso-scale electrodes (500 μm diameter) defined by silver ink casting followed by pulsed electroplating of gold or platinum without any masking procedure, (c) casting of a uniform and planar insulation layer via a novel process of confined precision spin coating (CPSC) of SU-8 which acts as a biocompatible insulation atop the meso-scale electrodes; and (d) selective laser micromachining to define the 50 μm × 50 μm microelectrodes. For an 8 × 8 array, the culture well and MEA chip framework are 3D printed as two separate parts and sealed together with a biocompatible epoxy as in commercially available MEAs. The fabricated MEAs have an average 1 kHz impedance of 36.8 kΩ/16 kΩ with a double layer capacitance of 400 nF cm−2/520 nF cm−2 for nano-porous platinum/nano-gold which is comparable to the state-of-art commercially available 2D MEAs. Additionally, it was found out that our 3D printing-based process compares very favorably with traditional glass MEAs in terms of design to device while representing a dramatic reduction in cost, timeline for fabrication, reduction in the number of steps and the need for sophisticated microfabrication and packaging equipment. “Makerspace microfabrication” with the use of simple tools and materials is used to demonstrate the realization of 2D microelectrode arrays (MEAs) having a density of up to 8 × 8 MEAs in under four days which are comparable to conventional MEAs.![]()
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Affiliation(s)
- Avra Kundu
- NanoScience Technology Center (NSTC)
- University of Central Florida
- Orlando
- USA
| | - Crystal Nattoo
- Department of Electrical and Computer Engineering
- University of Miami
- Coral Gables
- USA
| | - Sarah Fremgen
- NanoScience Technology Center (NSTC)
- University of Central Florida
- Orlando
- USA
| | - Sandra Springer
- NanoScience Technology Center (NSTC)
- University of Central Florida
- Orlando
- USA
| | - Tariq Ausaf
- NanoScience Technology Center (NSTC)
- University of Central Florida
- Orlando
- USA
- Department of Electrical & Computer Engineering
| | - Swaminathan Rajaraman
- NanoScience Technology Center (NSTC)
- University of Central Florida
- Orlando
- USA
- Department of Electrical & Computer Engineering
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13
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Neuroprotective role of hyperforin on aluminum maltolate-induced oxidative damage and apoptosis in PC12 cells and SH-SY5Y cells. Chem Biol Interact 2018; 299:15-26. [PMID: 30481499 DOI: 10.1016/j.cbi.2018.11.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 10/17/2018] [Accepted: 11/23/2018] [Indexed: 01/13/2023]
Abstract
Many reports demonstrated that aluminum maltolate (Almal) has potential toxicity to human and animal. Our study has demonstrated that Almal can induce oxidative damage and apoptosis in PC12 cells and SH-SY5Y Cells, two in vitro models of neuronal cells. Hyperforin (HF) is a well-known antioxidant, anti-inflammatory, anti-amyloid and anti-depressant compound extracted from Hypericum perforatum extract. Here, we investigated the neuroprotective effect of HF against Almal-induced neurotoxicity in cultured PC12 cells and SH-SY5Y cells, mainly caused by oxidative stress. In the present study, HF significantly inhibited the formation of reactive oxygen species (ROS), decreased the level of lipid peroxide and enhanced the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) compared with Almal group in PC12 cells and SH-SY5Y cells. Additionally, HF suppressed the reduction of the mitochondrial membrane potential (MMP), cytochrome c (Cyt-c) release, activation of caspase-3, and the down-regulation of Bcl-2 expression and up-regulation of Bax expression induced by Almal in PC12 cells and SH-SY5Y cells. In summary, HF protects PC12 cells and SH-SY5Y cells from damage induced by Almal through reducing oxidative stress and preventing of mitochondrial-mediated apoptosis.
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