1
|
Horne R, Ben-Shlomo N, Jensen M, Ellerman M, Escudero C, Hua R, Bennion D, Guymon CA, Hansen MR. Reducing the foreign body response on human cochlear implants and their materials in vivo with photografted zwitterionic hydrogel coatings. Acta Biomater 2023; 166:212-223. [PMID: 37187301 PMCID: PMC10330692 DOI: 10.1016/j.actbio.2023.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/27/2023] [Accepted: 05/04/2023] [Indexed: 05/17/2023]
Abstract
The foreign body response to implanted materials often complicates the functionality of sensitive biomedical devices. For cochlear implants, this response can reduce device performance, battery life and preservation of residual acoustic hearing. As a permanent and passive solution to the foreign body response, this work investigates ultra-low-fouling poly(carboxybetaine methacrylate) (pCBMA) thin film hydrogels that are simultaneously photo-grafted and photo-polymerized onto polydimethylsiloxane (PDMS). The cellular anti-fouling properties of these coatings are robustly maintained even after six-months subcutaneous incubation and over a broad range of cross-linker compositions. On pCBMA-coated PDMS sheets implanted subcutaneously, capsule thickness and inflammation are reduced significantly in comparison to uncoated PDMS or coatings of polymerized poly(ethylene glycol dimethacrylate) (pPEGDMA). Further, capsule thickness is reduced over a wide range of pCBMA cross-linker compositions. On cochlear implant electrode arrays implanted subcutaneously for one year, the coating bridges over the exposed platinum electrodes and dramatically reduces the capsule thickness over the entire implant. Coated cochlear implant electrode arrays could therefore lead to persistent improved performance and reduced risk of residual hearing loss. More generally, the in vivo anti-fibrotic properties of pCBMA coatings also demonstrate potential to mitigate the fibrotic response on a variety of sensing/stimulating implants. STATEMENT OF SIGNIFICANCE: This article presents, for the first time, evidence of the in vivo anti-fibrotic effect of zwitterionic hydrogel thin films photografted to polydimethylsiloxane (PDMS) and human cochlear implant arrays. The hydrogel coating shows no evidence of degradation or loss of function after long-term implantation. The coating process enables full coverage of the electrode array. The coating reduces fibrotic capsule thickness 50-70% over a broad range of cross-link densities for implantations from six weeks to one year.
Collapse
Affiliation(s)
- Ryan Horne
- University of Iowa Carver College of Medicine, United States of America; University of Iowa Department of Chemical and Biochemical Engineering, United States of America
| | - Nir Ben-Shlomo
- University of Iowa Hospitals and Clinics Department of Otolaryngology, United States of America
| | - Megan Jensen
- University of Iowa Hospitals and Clinics Department of Otolaryngology, United States of America
| | - Morgan Ellerman
- University of Iowa Department of Chemical and Biochemical Engineering, United States of America
| | - Caleb Escudero
- University of Iowa Carver College of Medicine, United States of America
| | - Rong Hua
- University of Iowa Hospitals and Clinics Department of Otolaryngology, United States of America
| | - Douglas Bennion
- University of Iowa Hospitals and Clinics Department of Otolaryngology, United States of America
| | - C Allan Guymon
- University of Iowa Department of Chemical and Biochemical Engineering, United States of America
| | - Marlan R Hansen
- University of Iowa Hospitals and Clinics Department of Otolaryngology, United States of America.
| |
Collapse
|
2
|
Dual Drug Delivery in Cochlear Implants: In Vivo Study of Dexamethasone Combined with Diclofenac or Immunophilin Inhibitor MM284 in Guinea Pigs. Pharmaceutics 2023; 15:pharmaceutics15030726. [PMID: 36986587 PMCID: PMC10058822 DOI: 10.3390/pharmaceutics15030726] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 02/24/2023] Open
Abstract
Cochlear implants are well established to treat severe hearing impairments. Despite many different approaches to reduce the formation of connective tissue after electrode insertion and to keep electrical impedances low, results are not yet satisfying. Therefore, the aim of the current study was to combine the incorporation of 5% dexamethasone in the silicone body of the electrode array with an additional polymeric coating releasing diclofenac or the immunophilin inhibitor MM284, some anti-inflammatory substances not yet tested in the inner ear. Guinea pigs were implanted for four weeks and hearing thresholds were determined before implantation and after the observation time. Impedances were monitored over time and, finally, connective tissue and the survival of spiral ganglion neurons (SGNs) were quantified. Impedances increased in all groups to a similar extent but this increase was delayed in the groups with an additional release of diclofenac or MM284. Using Poly-L-lactide (PLLA)-coated electrodes, the damage caused during insertion was much higher than without the coating. Only in these groups, connective tissue could extend to the apex of the cochlea. Despite this, numbers of SGNs were only reduced in PLLA and PLLA plus diclofenac groups. Even though the polymeric coating was not flexible enough, MM284 seems to especially have potential for further evaluation in connection with cochlear implantation.
Collapse
|
3
|
Recent Advances in Cochlear Implant Electrode Array Design Parameters. MICROMACHINES 2022; 13:mi13071081. [PMID: 35888898 PMCID: PMC9323156 DOI: 10.3390/mi13071081] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 02/04/2023]
Abstract
Cochlear implants are neural implant devices that aim to restore hearing in patients with severe sensorineural hearing impairment. Here, the main goal is to successfully place the electrode array in the cochlea to stimulate the auditory nerves through bypassing damaged hair cells. Several electrode and electrode array parameters affect the success of this technique, but, undoubtedly, the most important one is related to electrodes, which are used for nerve stimulation. In this paper, we provide a comprehensive resource on the electrodes currently being used in cochlear implant devices. Electrode materials, shape, and the effect of spacing between electrodes on the stimulation, stiffness, and flexibility of electrode-carrying arrays are discussed. The use of sensors and the electrical, mechanical, and electrochemical properties of electrode arrays are examined. A large library of preferred electrodes is reviewed, and recent progress in electrode design parameters is analyzed. Finally, the limitations and challenges of the current technology are discussed along with a proposal of future directions in the field.
Collapse
|
4
|
Luo Y, Chen A, Xu M, Chen D, Tang J, Ma D, Zhang H. Preparation, characterization, and in vitro/ vivo evaluation of dexamethasone/poly(ε-caprolactone)-based electrode coatings for cochlear implants. Drug Deliv 2021; 28:1673-1684. [PMID: 34347538 PMCID: PMC8344245 DOI: 10.1080/10717544.2021.1960927] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
With dexamethasone as the model drug and polycaprolactone (PCL) as the carrier material, a drug delivery coating for cochlear electrodes was prepared, to control cochlear fibrosis caused by cochlear implantation. A dexamethasone/poly (ε-caprolactone)-based electrode coating was prepared using the impregnation coating method. Preparation parameters were optimized, yielding 1 impregnation instance, impregnation time of 10 s, and PCL concentration of 10%. The coating was characterized in vitro using scanning electron microscopy, a universal machine, high-performance liquid chromatography, and CCK-8. The surface was porous and uniformly thick (average thickness, 48.67 µm)—with good flexibility, long-term slow drug release, and optimal drug concentration—and was biologically safe. The experimental results show that PCL is an ideal controlled-release material for dexamethasone as a drug carrier coating for cochlear implants.
Collapse
Affiliation(s)
- Yanjing Luo
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Anning Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Muqing Xu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Dongxiu Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| | - Jie Tang
- Hearing Research Center, Southern Medical University, Guangzhou, China.,Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China
| | - Dong Ma
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, China
| | - Hongzheng Zhang
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Hearing Research Center, Southern Medical University, Guangzhou, China
| |
Collapse
|
5
|
Interaction of micropatterned topographical and biochemical cues to direct neurite growth from spiral ganglion neurons. Hear Res 2021; 409:108315. [PMID: 34343850 DOI: 10.1016/j.heares.2021.108315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/07/2021] [Accepted: 07/12/2021] [Indexed: 01/01/2023]
Abstract
Functional outcomes with neural prosthetic devices, such as cochlear implants, are limited in part due to physical separation between the stimulating elements and the neurons they stimulate. One strategy to close this gap aims to precisely guide neurite regeneration to position the neurites in closer proximity to electrode arrays. Here, we explore the ability of micropatterned biochemical and topographic guidance cues, singly and in combination, to direct the growth of spiral ganglion neuron (SGN) neurites, the neurons targeted by cochlear implants. Photopolymerization of methacrylate monomers was used to form unidirectional topographical features of ridges and grooves in addition to multidirectional patterns with 90o angle turns. Microcontact printing was also used to create similar uni- and multi-directional patterns of peptides on polymer surfaces. Biochemical cues included peptides that facilitate (laminin, LN) or repel (EphA4-Fc) neurite growth. On flat surfaces, SGN neurites preferentially grew on LN-coated stripes and avoided EphA4-Fc-coated stripes. LN or EphA4-Fc was selectively adsorbed onto the ridges or grooves to test the neurite response to a combination of topographical and biochemical cues. Coating the ridges with EphA4-Fc and grooves with LN lead to enhanced SGN alignment to topographical patterns. Conversely, EphA4-Fc coating on the grooves or LN coating on the ridges tended to disrupt alignment to topographical patterns. SGN neurites respond to combinations of topographical and biochemical cues and surface patterning that leverages both cues enhance guided neurite growth.
Collapse
|
6
|
Quarterman JC, Geary SM, Salem AK. Evolution of drug-eluting biomedical implants for sustained drug delivery. Eur J Pharm Biopharm 2020; 159:21-35. [PMID: 33338604 DOI: 10.1016/j.ejpb.2020.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/19/2020] [Accepted: 12/08/2020] [Indexed: 02/06/2023]
Abstract
In the field of drug delivery, the most commonly used treatments have traditionally been systemically delivered using oral or intravenous administration. The problems associated with this type of delivery is that the drug concentration is controlled by first pass metabolism, and therefore may not always remain within the therapeutic window. Implantable drug delivery systems (IDDSs) are an excellent alternative to traditional delivery because they offer the ability to precisely control the drug release, deliver drugs locally to the target tissue, and avoid the toxic side effects often experienced with systemic administration. Since the creation of the first FDA-approved IDDS in 1990, there has been a surge in research devoted to fabricating and testing novel IDDS formulations. The versatility of these systems is evident when looking at the various biomedical applications that utilize IDDSs. This review provides an overview of the history of IDDSs, with examples of the different types of IDDS formulations, as well as looking at current and future biomedical applications for such systems. Though there are still obstacles that need to be overcome, ever-emerging new technologies are making the manufacturing of IDDSs a rewarding therapeutic endeavor with potential for further improvements.
Collapse
Affiliation(s)
- Juliana C Quarterman
- University of Iowa College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, 180 S. Grand Avenue, Iowa City, IA 52242, United States
| | - Sean M Geary
- University of Iowa College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, 180 S. Grand Avenue, Iowa City, IA 52242, United States
| | - Aliasger K Salem
- University of Iowa College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, 180 S. Grand Avenue, Iowa City, IA 52242, United States.
| |
Collapse
|
7
|
Hügl S, Scheper V, Gepp MM, Lenarz T, Rau TS, Schwieger J. Coating stability and insertion forces of an alginate-cell-based drug delivery implant system for the inner ear. J Mech Behav Biomed Mater 2019; 97:90-98. [DOI: 10.1016/j.jmbbm.2019.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/01/2019] [Accepted: 05/03/2019] [Indexed: 12/20/2022]
|
8
|
Griffo A, Liu Y, Mahlberg R, Alakomi HL, Johansson LS, Milani R. Design and Testing of a Bending-Resistant Transparent Nanocoating for Optoacoustic Cochlear Implants. ChemistryOpen 2019; 8:1100-1108. [PMID: 31406657 PMCID: PMC6682933 DOI: 10.1002/open.201900172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Indexed: 12/25/2022] Open
Abstract
A nanosized coating was designed to reduce fouling on the surface of a new type of cochlear implant relying on optoacoustic stimulation. This kind of device imposes novel design principles for antifouling coatings, such as optical transparency and resistance to significant constant bending. To reach this goal we deposited on poly(dimethylsiloxane) a PEO-based layer with negligible thickness compared to the curvature radius of the cochlea. Its antifouling performance was monitored upon storage by quartz crystal microbalance, and its resistance upon bending was tested by fluorescence microscopy under geometrical constraints similar to those of implantation. The coating displayed excellent antifouling features and good stability, and proved suitable for further testing in real-environment conditions.
Collapse
Affiliation(s)
- Alessandra Griffo
- VTT Technical Research Centre of Finland Ltd. P.O. Box 1000 FI-02044VTT Espoo Finland.,Department of Bioproducts and Biosystems Aalto University P.O. Box 16100 FI-00076Aalto Espoo Finland
| | - Yingying Liu
- VTT Technical Research Centre of Finland Ltd. P.O. Box 1000 FI-02044VTT Espoo Finland
| | - Riitta Mahlberg
- VTT Technical Research Centre of Finland Ltd. P.O. Box 1000 FI-02044VTT Espoo Finland
| | - Hanna-L Alakomi
- VTT Technical Research Centre of Finland Ltd. P.O. Box 1000 FI-02044VTT Espoo Finland
| | - Leena-S Johansson
- Department of Bioproducts and Biosystems Aalto University P.O. Box 16100 FI-00076Aalto Espoo Finland
| | - Roberto Milani
- VTT Technical Research Centre of Finland Ltd. P.O. Box 1000 FI-02044VTT Espoo Finland
| |
Collapse
|
9
|
Bas E, Anwar MR, Goncalves S, Dinh CT, Bracho OR, Chiossone JA, Van De Water TR. Laminin-coated electrodes improve cochlear implant function and post-insertion neuronal survival. Neuroscience 2019; 410:97-107. [PMID: 31059743 DOI: 10.1016/j.neuroscience.2019.04.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 04/17/2019] [Accepted: 04/24/2019] [Indexed: 12/20/2022]
Abstract
The benefits of Cochlear implant (CI) technology depend among other factors on the proximity of the electrode array to the spiral ganglion neurons. Laminin, a component of the extracellular matrix, regulates Schwann cell proliferation and survival as well as reorganization of actin fibers within their cytoskeleton, which is necessary for myelination of peripheral axons. In this study we explore the effectiveness of laminin-coated electrodes in promoting neuritic outgrowth from auditory neurons towards the electrode array and the ability to reduce acoustic and electric auditory brainstem response (i.e. aABR and eABR) thresholds. In vitro: Schwann cells and neurites are attracted towards laminin-coated surfaces with longer neuritic processes in laminin-coated dishes compared to uncoated dishes. In vivo: Animals implanted with laminin-coated electrodes experience significant decreases in eABR and aABR thresholds at selected frequencies compared to the results from the uncoated electrodes group. At 1 month post implantation there were a greater number of spiral ganglion neurons and neuritic processes projecting into the scala tympani of animals implanted with laminin-coated electrodes compared to animals with uncoated electrodes. These data suggest that Schwann cells are attracted towards laminin-coated electrodes and promote neuritic outgrowth/ guidance and promote the survival of spiral ganglion neurons following electrode insertion trauma.
Collapse
Affiliation(s)
- Esperanza Bas
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America.
| | - Mir R Anwar
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Stefania Goncalves
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Christine T Dinh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Olena R Bracho
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Juan A Chiossone
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Thomas R Van De Water
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States of America
| |
Collapse
|
10
|
Yang GG, Hao L, Cao Q, Zhang H, Yang J, Ji LN, Mao ZW. Three-in-One Self-Assembled Nanocarrier for Dual-Drug Delivery, Two-Photon Imaging, and Chemo-Photodynamic Synergistic Therapy. ACS APPLIED MATERIALS & INTERFACES 2018; 10:28301-28313. [PMID: 30063824 DOI: 10.1021/acsami.8b07270] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We herein present a three-in-one nanoplatform (named Fu/LD@RuCD) for dual-drug delivery, two-photon imaging, and chemo-photodynamic synergistic therapy, enabled by simple self-assembly between adamantine-functionalized ruthenium complexes ([Ru(phen-ad)3](PF6)2, Ru) and natural cyclodextrin (β-CD) monomers. By host-guest chemistry, nanocarrier RuCD 70-90 nm in diameter is fabricated through a very simple mixing step in water at room temperature, in which the octahedral configuration of Ru complex provides a rigid skeleton and the hydrogen bonding of secondary hydroxyl groups formed between two adjacent β-CD monomers displays a bridging role allowing for three-dimensional architectures. The dual-drug-loaded nanoparticle Fu/LD@RuCD (Fu: 5-fluorouracil; LD: lonidamine) effectively penetrates into cancer cells in 8 h and selectively accumulates in lysosomes, in which dual-drug release is promoted by the mildly acidic environment. Under visible light irradiation, nanocarrier RuCD exhibits excellent photodynamic therapy capability by producing sufficient reactive oxygen species and damaging lysosomes, accordingly 5-fluorouracil and lonidamine can escape from lysosomes and reach their sites of action, resulting in mitochondria dysfunction and cancer cell apoptosis. Simultaneously, the excellent photophysical properties of the nanocarrier enable the facile track of drug delivery under one-photon and two-photon excitation. Moreover, in vivo anticancer investigations show that Fu/LD@RuCD can effectively inhibit the tumor growth without systemic side effects by chemo-photodynamic synergistic therapy, and the therapeutic effect is better than the free anticancer drugs and the sole therapeutic modality.
Collapse
Affiliation(s)
- Gang-Gang Yang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Liang Hao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Qian Cao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Hang Zhang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Jing Yang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Liang-Nian Ji
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| | - Zong-Wan Mao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , P. R. China
| |
Collapse
|
11
|
Xu M, Ma D, Chen D, Cai J, He Q, Shu F, Tang J, Zhang H. Preparation, characterization and application research of a sustained dexamethasone releasing electrode coating for cochlear implantation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 90:16-26. [PMID: 29853079 DOI: 10.1016/j.msec.2018.04.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 03/24/2018] [Accepted: 04/15/2018] [Indexed: 10/17/2022]
Abstract
Cochlear inflammatory response after cochlear implantation (CI) is an important mechanism for implantation trauma and hearing loss. The hearing loss was also caused by damage to auditory hair cells (HCs), whereas ion homeostasis within the cochlea can ensure survival of HCs. In our study, pure hyaluronic acid (HA) was crosslinked with 1, 4-butanediol diglycidyl ether (BDDE) and the successful preparation of the cross-linked hydrogel (CHA) was confirmed by rheological characteristics and FTIR spectra. Artificial perilymph (APL) was prepared to simulate the ion homeostasis microenvironment within scala tympani of human cochlear, and served as the major component of artificial perilymph soaked CHA (APL-CHA). The conductivity experiment indicated that APL-CHA is more suitable to the requirements of the electrical conductivity in scala tympani. The electrode coating process found that the extrusion coating method have advantages of controllable adhesive capacity of APL-CHA, uniform coating thickness and smooth surface as compared to common method. Due to CI surgery application requirement, optimization of coating process was selected as follows: extrusion coating method, degree of 3.6 vol%, pinhole diameter of 32G (110 μm), pressure of 200 ± 15.81 Psi. Controlled dexamethasone 21-phosphate sodium salt (DSP) release of 20 days could be demonstrated using the hydrogel filled reservoir via a validated HPLC method. The morphological structure of CHA showed different sizes of porous structure among APL-CHA provided structural basis for drug delivery. L929 fibroblasts culture and Spiral Ganglion Neuron Explants culture results revealed that APL-CHA possesses fine biological compatibility. APL-CHA shows a promising application in CI surgery and has great potential in preventing hearing loss with well simulation of ion homeostasis within the cochlear, local DSP delivery for target anti-inflammatory, approximate conductivity within the scala tympani and optimization of electrode coating process.
Collapse
Affiliation(s)
- Muqing Xu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Dong Ma
- Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou 510632, China
| | - Dongxiu Chen
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Jieqing Cai
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Qiaofang He
- Operating Room of Anesthesiology Department, Zhujiang Hospital of Southern Medical University, Guangzhou 510282, China
| | - Fan Shu
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Jie Tang
- Department of Physiology, School of Basic Medical Sciences, Institute of Mental Health, Southern Medical University, Guangzhou, 510515, China
| | - Hongzheng Zhang
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China.
| |
Collapse
|
12
|
Mäder K, Lehner E, Liebau A, Plontke SK. Controlled drug release to the inner ear: Concepts, materials, mechanisms, and performance. Hear Res 2018; 368:49-66. [PMID: 29576310 DOI: 10.1016/j.heares.2018.03.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/21/2018] [Accepted: 03/06/2018] [Indexed: 12/01/2022]
Abstract
Progress in drug delivery to the ear has been achieved over the last few years. This review illustrates the main mechanisms of controlled drug release and the resulting geometry- and size-dependent release kinetics. The potency, physicochemical properties, and stability of the drug molecules are key parameters for designing the most suitable drug delivery system. The most important drug delivery systems for the inner ear include solid foams, hydrogels, and different nanoscale drug delivery systems (e.g., nanoparticles, liposomes, lipid nanocapsules, polymersomes). Their main characteristics (i.e., general structure and materials) are discussed, with special attention given to underlining the link between the physicochemical properties (e.g., surface areas, glass transition temperature, microviscosity, size, and shape) and release kinetics. An appropriate characterization of the drug, the excipients used, and the formulated drug delivery systems is necessary to achieve a deeper understanding of the release process and decrease variability originating from the drug delivery system. This task cannot be solved by otologists alone. The interdisciplinary cooperation between otology/neurotology, pharmaceutics, physics, and other disciplines will result in improved drug delivery systems for the inner ear.
Collapse
Affiliation(s)
- Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120 Halle (Saale), Germany.
| | - Eric Lehner
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120 Halle (Saale), Germany
| | - Arne Liebau
- Department of Otorhinolaryngology, Head & Neck Surgery, Martin Luther University Halle-Wittenberg, University Medicine Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
| | - Stefan K Plontke
- Department of Otorhinolaryngology, Head & Neck Surgery, Martin Luther University Halle-Wittenberg, University Medicine Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
| |
Collapse
|
13
|
Dencker F, Dreyer L, Müller D, Zernetsch H, Paasche G, Sindelar R, Glasmacher B. A silicone fiber coating as approach for the reduction of fibroblast growth on implant electrodes. J Biomed Mater Res B Appl Biomater 2016; 105:2574-2580. [PMID: 27701814 DOI: 10.1002/jbm.b.33798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 08/19/2016] [Accepted: 09/12/2016] [Indexed: 11/11/2022]
Abstract
In cochlear implant (CI) patients, an increase in electrode impedance due to fibrotic encapsulation is frequently observed. Several attempts have been proposed to reduce fibroblast growth at the electrode contacts, but none proved to be satisfactory so far. Here, a silicone fiber coating of the electrode contacts is presented that provides a complex micro-scale surface topography and increases hydrophobicity to inhibit fibroblast growth and adhesion. A silicone fiber electrospinning process was developed to create a thin and porous fiber mesh. Fiber coatings were applied on graphite specimen holders, glass cover slips and CI electrode contacts. For characterization of the coating's pore distribution, water contact angle and electrical impedance were analyzed. Cytotoxicity and in vitro fibroblast growth were evaluated to assess biological efficacy of the coatings. It could be shown that the silicone fiber mesh itself had only minor influence on electrode impedance. A uniform, hydrophobic fiber coating could be achieved that decreased fibroblast growth without showing toxic effects. Finally, CI electrode contacts were successfully coated in order to present this promising approach for a long-term improvement of CI electrodes. We are one of the first groups that could successfully adapt the electrospinning technique on the utilization of silicone. Silicone was chosen because of its high hydrophobicity, chemical stability and excellent biocompatibility and as it is one of the biomaterials already used in CIs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2574-2580, 2017.
Collapse
Affiliation(s)
- Folke Dencker
- Department of Material Science, Faculty II, University of Applied Sciences and Arts Hannover, Germany.,Institute of Micro Production Technology, Leibniz Universität Hannover, Germany
| | - Lutz Dreyer
- Institute for Multiphase Processes, Leibniz Universität Hannover, Germany
| | - Dietrich Müller
- Department of Material Science, Faculty II, University of Applied Sciences and Arts Hannover, Germany
| | - Holger Zernetsch
- Institute for Multiphase Processes, Leibniz Universität Hannover, Germany
| | - Gerrit Paasche
- Department of Otolaryngology, Hannover Medical School, Germany.,Cluster of Excellence "Hearing4all", Hannover Medical School, Germany
| | - Ralf Sindelar
- Department of Material Science, Faculty II, University of Applied Sciences and Arts Hannover, Germany
| | - Birgit Glasmacher
- Institute for Multiphase Processes, Leibniz Universität Hannover, Germany
| |
Collapse
|
14
|
Mau R, Oldorf P, Peters R, Seitz H. Adjusting inkjet printhead parameters to deposit drugs into micro-sized reservoirs. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2016. [DOI: 10.1515/cdbme-2016-0086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractDrug delivery systems (DDS) ensure that therapeutically effective drug concentrations are delivered locally to the target site. For that reason, it is common to coat implants with a degradable polymer which contains drugs. However, the use of polymers as a drug carrier has been associated with adverse side effects. For that reason, several technologies have been developed to design polymer-free DDS. In literature it has been shown that micro-sized reservoirs can be applied as drug reservoirs. Inkjet techniques are capable of depositing drugs into these reservoirs. In this study, two different geometries of micro-sized reservoirs have been laden with a drug (ASA) using a drop-on-demand inkjet printhead. Correlations between the characteristics of the drug solution, the operating parameters of the printhead and the geometric parameters of the reservoir are shown. It is indicated that wettability of the surface play a key role for drug deposition into micro-sized reservoirs.
Collapse
Affiliation(s)
- Robert Mau
- 1University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, 18059 Rostock, Germany
| | - Paul Oldorf
- 2Schweißtechnische Lehr- und Versuchsanstalt Mecklenburg-Vorpommern GmbH, Alter Hafen Süd 4, 18069 Rostock, Germany
| | - Rigo Peters
- 2Schweißtechnische Lehr- und Versuchsanstalt Mecklenburg-Vorpommern GmbH, Alter Hafen Süd 4, 18069 Rostock, Germany
| | - Hermann Seitz
- 1University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, 18059 Rostock, Germany
| |
Collapse
|
15
|
Kumar S, Maiti P. Controlled biodegradation of polymers using nanoparticles and its application. RSC Adv 2016. [DOI: 10.1039/c6ra08641a] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Controlled biodegradation mechanism has been revealed using different nanoparticles which eventually regulate pH of media.
Collapse
Affiliation(s)
- Sunil Kumar
- School of Materials Science and Technology
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi 221 005
- India
| | - Pralay Maiti
- School of Materials Science and Technology
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi 221 005
- India
| |
Collapse
|
16
|
Recent advances in local drug delivery to the inner ear. Int J Pharm 2015; 494:83-101. [PMID: 26260230 DOI: 10.1016/j.ijpharm.2015.08.015] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/31/2015] [Accepted: 08/05/2015] [Indexed: 12/14/2022]
Abstract
Inner ear diseases are not adequately treated by systemic drug administration mainly because of the blood-perilymph barrier that reduces exchanges between plasma and inner ear fluids. Local drug delivery methods including intratympanic and intracochlear administrations are currently developed to treat inner ear disorders more efficiently. Intratympanic administration is minimally invasive but relies on diffusion through middle ear barriers for drug entry into the cochlea, whereas intracochlear administration offers direct access to the colchlea but is rather invasive. A wide range of drug delivery systems or devices were evaluated in research and clinic over the last decade for inner ear applications. In this review, different strategies including medical devices, hydrogels and nanoparticulate systems for intratympanic administration, and cochlear implant coating or advanced medical devices for intracoclear administration were explored with special attention to in vivo studies. This review highlights the promising systems for future clinical applications as well as the current hurdles that remain to be overcome for efficient inner ear therapy.
Collapse
|
17
|
Glueckert R, Pritz CO, Roy S, Dudas J, Schrott-Fischer A. Nanoparticle mediated drug delivery of rolipram to tyrosine kinase B positive cells in the inner ear with targeting peptides and agonistic antibodies. Front Aging Neurosci 2015; 7:71. [PMID: 26042029 PMCID: PMC4436893 DOI: 10.3389/fnagi.2015.00071] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/20/2015] [Indexed: 12/22/2022] Open
Abstract
Aim: Systemic pharmacotherapies have limitation due to blood-labyrinth barrier, so local delivery via the round window membrane opens a path for effective treatment. Multifunctional nanoparticle (NP)-mediated cell specific drug delivery may enhance efficacy and reduce side effects. Different NPs with ligands to target TrkB receptor were tested. Distribution, uptake mechanisms, trafficking, and bioefficacy of drug release of rolipram loaded NPs were evaluated. Methods: We tested lipid based nanocapsules (LNCs), Quantum Dot, silica NPs with surface modification by peptides mimicking TrkB or TrkB activating antibodies. Bioefficacy of drug release was tested with rolipram loaded LNCs to prevent cisplatin-induced apoptosis. We established different cell culture models with SH-SY-5Y and inner ear derived cell lines and used neonatal and adult mouse explants. Uptake and trafficking was evaluated with FACS and confocal as well as transmission electron microscopy. Results: Plain NPs show some selectivity in uptake related to the in vitro system properties, carrier material, and NP size. Some peptide ligands provide enhanced targeted uptake to neuronal cells but failed to show this in cell cultures. Agonistic antibodies linked to silica NPs showed TrkB activation and enhanced binding to inner ear derived cells. Rolipram loaded LNCs proved as effective carriers to prevent cisplatin-induced apoptosis. Discussion: Most NPs with targeting ligands showed limited effects to enhance uptake. NP aggregation and unspecific binding may change uptake mechanisms and impair endocytosis by an overload of NPs. This may affect survival signaling. NPs with antibodies activate survival signaling and show effective binding to TrkB positive cells but needs further optimization for specific internalization. Bioefficiacy of rolipram release confirms LNCs as encouraging vectors for drug delivery of lipophilic agents to the inner ear with ideal release characteristics independent of endocytosis.
Collapse
Affiliation(s)
- Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck Innsbruck, Austria ; University Clinics of Innsbruck, Tiroler Landeskrankenanstalten GmbH-TILAK Innsbruck, Austria
| | - Christian O Pritz
- Department of Otolaryngology, Medical University of Innsbruck Innsbruck, Austria ; Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem Jerusalem, Israel
| | - Soumen Roy
- Department of Otolaryngology, Medical University of Innsbruck Innsbruck, Austria
| | - Jozsef Dudas
- Department of Otolaryngology, Medical University of Innsbruck Innsbruck, Austria
| | | |
Collapse
|