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Wellens J, Deschaume O, Putzeys T, Eyley S, Thielemans W, Verhaert N, Bartic C. Sulfobetaine-based ultrathin coatings as effective antifouling layers for implantable neuroprosthetic devices. Biosens Bioelectron 2023; 226:115121. [PMID: 36774733 DOI: 10.1016/j.bios.2023.115121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 02/05/2023]
Abstract
Foreign body response (FBR), inflammation, and fibrotic encapsulation of neural implants remain major problems affecting the impedance of the electrode-tissue interface and altering the device performance. Adhesion of proteins and cells (e.g., pro-inflammatory macrophages, and fibroblasts) triggers the FBR cascade and can be diminished by applying antifouling coatings onto the implanted devices. In this paper, we report the deposition and characterization of a thin (±6 nm) sulfobetaine-based coating onto microfabricated platinum electrodes and cochlear implant (CI) electrode arrays. We found that this coating has stable cell and protein-repellent properties, for at least 31 days in vitro, not affected by electrical stimulation protocols. Additionally, its effect on the electrochemical properties relevant to stimulation (i.e., impedance, charge injection capacity) was negligible. When applied to clinical CI electrode arrays, the film was successful at inhibiting fibroblast adhesion on both the silicone packaging and the platinum/iridium electrodes. In vitro, in fibroblast cultures, coated CI electrode arrays maintained impedance values up to five times lower compared to non-coated devices. Our studies demonstrate that such thin sulfobetaine containing layers are stable and prevent protein and cell adhesion in vitro and are compatible for use on CI electrode arrays. Future in vivo studies should be conducted to investigate its ability to mitigate biofouling, fibrosis, and the resulting impedance changes upon long-term implantation in vivo.
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Affiliation(s)
- Jolan Wellens
- Laboratory for Soft Matter and Biophysics, Dept. Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
| | - Olivier Deschaume
- Laboratory for Soft Matter and Biophysics, Dept. Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
| | - Tristan Putzeys
- Laboratory for Soft Matter and Biophysics, Dept. Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium; Experimental Oto-rhino-laryngology Research Group, Dept. Neuroscience, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Samuel Eyley
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, Campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500, Kortrijk, Belgium
| | - Wim Thielemans
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, Campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500, Kortrijk, Belgium
| | - Nicolas Verhaert
- Experimental Oto-rhino-laryngology Research Group, Dept. Neuroscience, KU Leuven, Herestraat 49, 3000, Leuven, Belgium; Department of Otorhinolaryngology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Carmen Bartic
- Laboratory for Soft Matter and Biophysics, Dept. Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium.
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Rahman MT, Chari DA, Ishiyama G, Lopez I, Quesnel AM, Ishiyama A, Nadol JB, Hansen MR. Cochlear implants: Causes, effects and mitigation strategies for the foreign body response and inflammation. Hear Res 2022; 422:108536. [PMID: 35709579 PMCID: PMC9684357 DOI: 10.1016/j.heares.2022.108536] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 04/20/2022] [Accepted: 05/23/2022] [Indexed: 12/15/2022]
Abstract
Cochlear implants provide effective auditory rehabilitation for patients with severe to profound sensorineural hearing loss. Recent advances in cochlear implant technology and surgical approaches have enabled a greater number of patients to benefit from this technology, including those with significant residual low frequency acoustic hearing. Nearly all cochleae implanted with a cochlear implant electrode array develop an inflammatory and fibrotic response. This tissue reaction can have deleterious consequences for implant function, residual acoustic hearing, and the development of the next generation of cochlear prosthetics. This article reviews the current understanding of the inflammatory/foreign body response (FBR) after cochlear implant surgery, its impact on clinical outcome, and therapeutic strategies to mitigate this response. Findings from both in human subjects and animal models across a variety of species are highlighted. Electrode array design, surgical techniques, implant materials, and the degree and type of electrical stimulation are some critical factors that affect the FBR and inflammation. Modification of these factors and various anti-inflammatory pharmacological interventions have been shown to mitigate the inflammatory/FBR response. Ongoing and future approaches that seek to limit surgical trauma and curb the FBR to the implanted biomaterials of the electrode array are discussed. A better understanding of the anatomical, cellular and molecular basis of the inflammatory/FBR response after cochlear implantation has the potential to improve the outcome of current cochlear implants and also facilitate the development of the next generation of neural prostheses.
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Affiliation(s)
- Muhammad T Rahman
- Department of Otolaryngology-Head & Neck Surgery, University of Iowa, Iowa City, IA, USA
| | - Divya A Chari
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Gail Ishiyama
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Ivan Lopez
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Alicia M Quesnel
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Akira Ishiyama
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Joseph B Nadol
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Marlan R Hansen
- Department of Otolaryngology-Head & Neck Surgery, University of Iowa, Iowa City, IA, USA.
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Brant JA, Adewole DO, Vitale F, Cullen DK. Bioengineering applications for hearing restoration: emerging biologically inspired and biointegrated designs. Curr Opin Biotechnol 2021; 72:131-138. [PMID: 34826683 DOI: 10.1016/j.copbio.2021.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 10/29/2021] [Accepted: 11/08/2021] [Indexed: 12/21/2022]
Abstract
Cochlear implantation has become the standard of care for hearing loss not amenable to amplification by bypassing the structures of the cochlea and stimulating the spiral ganglion neurons directly. Since the first single channel electrodes were implanted, significant advancements have been made: multi-channel arrays are now standard, they are softer to avoid damage to the cochlea and pre-curved to better position the electrode array adjacent to the nerve, and surgical and stimulation techniques have helped to conform to the anatomy and physiology of the cochlea. However, even with these advances the experience does not approach that of normal hearing. In order to make significant advances in performance, the next generation of implants will require novel interface technology. Advances in regenerative techniques, optogenetics, piezoelectric materials, and bioengineered living scaffolds hold the promise for the next generation of implantable hearing devices, and hope for the restoration of natural hearing.
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Affiliation(s)
- Jason A Brant
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA; Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 240 S. 33rd St., 301 Hayden Hall, Philadelphia, PA 19104, USA
| | - Dayo O Adewole
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA; Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 240 S. 33rd St., 301 Hayden Hall, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied, Science, University of Pennsylvania, 220 S 33rd St., Philadelphia, PA 19104, USA; Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA 19104, USA; Center for Neuroengineering & Therapeutics, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA
| | - Flavia Vitale
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 240 S. 33rd St., 301 Hayden Hall, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied, Science, University of Pennsylvania, 220 S 33rd St., Philadelphia, PA 19104, USA; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA; Department of Physical Medicine & Rehabilitation, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA; Center for Neuroengineering & Therapeutics, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA
| | - Daniel K Cullen
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 240 S. 33rd St., 301 Hayden Hall, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied, Science, University of Pennsylvania, 220 S 33rd St., Philadelphia, PA 19104, USA; Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA 19104, USA; Center for Neuroengineering & Therapeutics, University of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA.
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Comparison of Six Different Silicones In Vitro for Application as Glaucoma Drainage Device. MATERIALS 2018; 11:ma11030341. [PMID: 29495462 PMCID: PMC5872920 DOI: 10.3390/ma11030341] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/30/2018] [Accepted: 02/24/2018] [Indexed: 12/28/2022]
Abstract
Silicones are widely used in medical applications. In ophthalmology, glaucoma drainage devices are utilized if conservative therapies are not applicable or have failed. Long-term success of these devices is limited by failure to control intraocular pressure due to fibrous encapsulation. Therefore, different medical approved silicones were tested in vitro for cell adhesion, cell proliferation and viability of human Sclera (hSF) and human Tenon fibroblasts (hTF). The silicones were analysed also depending on the sample preparation according to the manufacturer's instructions. The surface quality was characterized with environmental scanning electron microscope (ESEM) and water contact angle measurements. All silicones showed homogeneous smooth and hydrophobic surfaces. Cell adhesion was significantly reduced on all silicones compared to the negative control. Proliferation index and cell viability were not influenced much. For development of a new glaucoma drainage device, the silicones Silbione LSR 4330 and Silbione LSR 4350, in this study, with low cell counts for hTF and low proliferation indices for hSF, and silicone Silastic MDX4-4210, with low cell counts for hSF and low proliferation indices for hTF, have shown the best results in vitro. Due to the high cell adhesion shown on Silicone LSR 40, 40,026, this material is unsuitable.
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