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Greco JA, Wagner NL, Jensen RJ, Lawrence DB, Ranaghan MJ, Sandberg MN, Sandberg DJ, Birge RR. Activation of retinal ganglion cells using a biomimetic artificial retina. J Neural Eng 2021; 18. [PMID: 34768254 DOI: 10.1088/1741-2552/ac395c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 11/12/2021] [Indexed: 11/12/2022]
Abstract
Objective.Biomimetic protein-based artificial retinas offer a new paradigm for restoring vision for patients blinded by retinal degeneration. Artificial retinas, comprised of an ion-permeable membrane and alternating layers of bacteriorhodopsin (BR) and a polycation binder, are assembled using layer-by-layer electrostatic adsorption. Upon light absorption, the oriented BR layers generate a unidirectional proton gradient. The main objective of this investigation is to demonstrate the ability of the ion-mediated subretinal artificial retina to activate retinal ganglion cells (RGCs) of degenerated retinal tissue.Approach. Ex vivoextracellular recording experiments with P23H line 1 rats are used to measure the response of RGCs following selective stimulation of our artificial retina using a pulsed light source. Single-unit recording is used to evaluate the efficiency and latency of activation, while a multielectrode array (MEA) is used to assess the spatial sensitivity of the artificial retina films.Main results.The activation efficiency of the artificial retina increases with increased incident light intensity and demonstrates an activation latency of ∼150 ms. The results suggest that the implant is most efficient with 200 BR layers and can stimulate the retina using light intensities comparable to indoor ambient light. Results from using an MEA show that activation is limited to the targeted receptive field.Significance.The results of this study establish potential effectiveness of using an ion-mediated artificial retina to restore vision for those with degenerative retinal diseases, including retinitis pigmentosa.
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Affiliation(s)
- Jordan A Greco
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, United States of America
| | - Nicole L Wagner
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, United States of America.,Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269, United States of America
| | - Ralph J Jensen
- VA Boston Healthcare System, 150 South Huntington Avenue, Boston, MA 02130, United States of America
| | - Daniel B Lawrence
- University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, CT 06032, United States of America
| | - Matthew J Ranaghan
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269, United States of America
| | - Megan N Sandberg
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, United States of America
| | - Daniel J Sandberg
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, United States of America
| | - Robert R Birge
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, United States of America.,Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269, United States of America
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Rohiwal SS, Ellederová Z, Ardan T, Klima J. Advancement in Nanostructure-Based Tissue-Engineered Biomaterials for Retinal Degenerative Diseases. Biomedicines 2021; 9:biomedicines9081005. [PMID: 34440209 PMCID: PMC8393745 DOI: 10.3390/biomedicines9081005] [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] [Received: 07/08/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/20/2022] Open
Abstract
The review intends to overview a wide range of nanostructured natural, synthetic and biological membrane implants for tissue engineering to help in retinal degenerative diseases. Herein, we discuss the transplantation strategies and the new development of material in combination with cells such as induced pluripotent stem cells (iPSC), mature retinal cells, adult stem cells, retinal progenitors, fetal retinal cells, or retinal pigment epithelial (RPE) sheets, etc. to be delivered into the subretinal space. Retinitis pigmentosa and age-related macular degeneration (AMD) are the most common retinal diseases resulting in vision impairment or blindness by permanent loss in photoreceptor cells. Currently, there are no therapies that can repair permanent vision loss, and the available treatments can only delay the advancement of retinal degeneration. The delivery of cell-based nanostructure scaffolds has been presented to enrich cell survival and direct cell differentiation in a range of retinal degenerative models. In this review, we sum up the research findings on different types of nanostructure scaffolds/substrate or material-based implants, with or without cells, used to deliver into the subretinal space for retinal diseases. Though, clinical and pre-clinical trials are still needed for these transplants to be used as a clinical treatment method for retinal degeneration.
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Leigh BL, Truong K, Bartholomew R, Ramirez M, Hansen MR, Allan Guymon C. Tuning Surface and Topographical Features to Investigate Competitive Guidance of Spiral Ganglion Neurons. ACS APPLIED MATERIALS & INTERFACES 2017; 9:31488-31496. [PMID: 28841276 PMCID: PMC6341486 DOI: 10.1021/acsami.7b09258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Cochlear Implants (CIs) suffer from limited tonal resolution due, in large part, to spatial separation between stimulating electrode arrays and primary neural receptors. In this work, a combination of physical and chemical micropatterns, formed on acrylate polymers, are used to direct the growth of primary spiral ganglion neurons (SGNs), the inner ear neurons. Utilizing the inherent temporal and spatial control of photopolymerization, physical microgrooves are fabricated using a photomask in a single step process. Biochemical patterns are generated by adsorbing laminin, a cell adhesion protein, to acrylate polymer surfaces followed by irradiation through a photomask with UV light to deactivate protein in exposed areas and generate parallel biochemical patterns. Laminin deactivation was shown increase as a function of UV light exposure while remaining adsorbed to the polymer surface. SGN neurites show alignment to both biochemical and physical patterns when evaluated individually. Competing biochemical and physical patterns were also examined. The relative guiding strength of physical cues was varied by independently changing both the amplitude and the band spacing of the microgrooves, with higher amplitudes and shorter band spacing providing cues that more effective guide neurite growth. SGN neurites aligned to laminin patterns with lower physical pattern amplitude and thus weaker physical cues. Alignment of SGNs shifted toward the physical pattern with higher amplitude and lower periodicity patterns which represent stronger cues. These results demonstrate the ability of photopolymerized microfeatures to modulate alignment of inner ear neurites even in the presence of conflicting physical and biochemical cues laying the groundwork for next generation cochlear implants and neural prosthetic devices.
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Affiliation(s)
- Braden L. Leigh
- Departments of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Kristy Truong
- Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
| | - Reid Bartholomew
- Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
| | - Mark Ramirez
- Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
| | - Marlan R. Hansen
- Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, USA
- Neurosurgery, University of Iowa, Iowa City, IA 52242, USA
| | - C. Allan Guymon
- Departments of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242, USA
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Ulkoski D, Meister A, Busse K, Kressler J, Scholz C. Synthesis and structure formation of block copolymers of poly(ethylene glycol) with homopolymers and copolymers of l-glutamic acid γ-benzyl ester and l-leucine in water. Colloid Polym Sci 2015. [DOI: 10.1007/s00396-015-3632-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Obeid R, Armstrong T, Peng X, Busse K, Kressler J, Scholz C. The behavior of poly(amino acids) containing
l
‐cysteine and their block copolymers with poly(ethylene glycol) on gold surfaces. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pola.26997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Rodolphe Obeid
- Department of ChemistryUniversity of Alabama in HuntsvilleHuntsville Alabama35899
| | - Tracy Armstrong
- Department of ChemistryUniversity of Alabama in HuntsvilleHuntsville Alabama35899
| | - Xiaoju Peng
- Department of ChemistryMartin Luther University of Halle‐WittenbergD‐06099Halle (Saale) Germany
| | - Karsten Busse
- Department of ChemistryMartin Luther University of Halle‐WittenbergD‐06099Halle (Saale) Germany
| | - Jörg Kressler
- Department of ChemistryMartin Luther University of Halle‐WittenbergD‐06099Halle (Saale) Germany
| | - Carmen Scholz
- Department of ChemistryUniversity of Alabama in HuntsvilleHuntsville Alabama35899
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Kompella UB, Amrite AC, Pacha Ravi R, Durazo SA. Nanomedicines for back of the eye drug delivery, gene delivery, and imaging. Prog Retin Eye Res 2013; 36:172-98. [PMID: 23603534 DOI: 10.1016/j.preteyeres.2013.04.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 03/28/2013] [Accepted: 04/04/2013] [Indexed: 01/25/2023]
Abstract
Treatment and management of diseases of the posterior segment of the eye such as diabetic retinopathy, retinoblastoma, retinitis pigmentosa, and choroidal neovascularization is a challenging task due to the anatomy and physiology of ocular barriers. For instance, traditional routes of drug delivery for therapeutic treatment are hindered by poor intraocular penetration and/or rapid ocular elimination. One possible approach to improve ocular therapy is to employ nanotechnology. Nanomedicines, products of nanotechnology, having at least one dimension in the nanoscale include nanoparticles, micelles, nanotubes, and dendrimers, with and without targeting ligands. Nanomedicines are making a significant impact in the fields of ocular drug delivery, gene delivery, and imaging, the focus of this review. Key applications of nanotechnology discussed in this review include a) bioadhesive nanomedicines; b) functionalized nanomedicines that enhance target recognition and/or cell entry; c) nanomedicines capable of controlled release of the payload; d) nanomedicines capable of enhancing gene transfection and duration of transfection; f) nanomedicines responsive to stimuli including light, heat, ultrasound, electrical signals, pH, and oxidative stress; g) diversely sized and colored nanoparticles for imaging, and h) nanowires for retinal prostheses. Additionally, nanofabricated delivery systems including implants, films, microparticles, and nanoparticles are described. Although the above nanomedicines may be administered by various routes including topical, intravitreal, intravenous, transscleral, suprachoroidal, and subretinal routes, each nanomedicine should be tailored for the disease, drug, and site of administration. In addition to the nature of materials used in nanomedicine design, depending on the site of nanomedicine administration, clearance and toxicity are expected to differ.
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Affiliation(s)
- Uday B Kompella
- Nanomedicine and Drug Delivery Laboratory, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
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Amanat N, James NL, McKenzie DR. Welding methods for joining thermoplastic polymers for the hermetic enclosure of medical devices. Med Eng Phys 2010; 32:690-9. [DOI: 10.1016/j.medengphy.2010.04.011] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 02/18/2010] [Accepted: 04/12/2010] [Indexed: 12/01/2022]
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Bayram C, Denkbaş EB, Kiliçay E, Hazer B, Çakmak HB, Noda I. Preparation and Characterization of Triamcinolone Acetonide-loaded Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) Microspheres. J BIOACT COMPAT POL 2008. [DOI: 10.1177/0883911508092790] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Triamcinolone acetonide loaded in poly(3-hydroxybutyrate-co-3 hydroxyhexanoate) (PHBHx) microspheres were prepared to treat cystoid macular oedema (CMO) and acute posterior segment inflammation associated with uveitis. The PHBHx microspheres were prepared by solvent evaporation technique using methylene chloride as the solvent and aqueous poly(vinyl alcohol) emulsifier as the dispersion medium. The PHBHx microspheres obtained were well formed with narrow size distribution; the average size prepared ranged from 40—200 μm depending on the formulation used. The stirring rate of the dispersion medium, emulsifier concentration, and polymer/solvent ratio parameters were varied to determine their effect on the size and size distribution of the PHBHx microspheres. Increasing the stirring rate and emulsifier concentration decreased the size and the size distribution of the microspheres, while increasing the polymer/solvent ratio caused the opposite effect. The polymer/drug ratio was the most effective parameter for controlling drug loading and release properties. More than 90% of the loaded drug was released within the first 24 h; after that, the release rate was slower for all formulations.
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Affiliation(s)
- Cem Bayram
- Hacettepe University, Chemistry Department, Biochemistry Division Beytepe, Ankara, Turkey
| | - Emir Baki Denkbaş
- Hacettepe University, Chemistry Department, Biochemistry Division Beytepe, Ankara, Turkey,
| | - Ebru Kiliçay
- Karaelmas University, Chemistry Department, Physical Chemistry Division, Zonguldak, Turkey
| | - Baki Hazer
- Karaelmas University, Chemistry Department, Physical Chemistry Division, Zonguldak, Turkey
| | - Hasan Basri Çakmak
- Ministry of Health, Atatürk Training Hospital, Ophthalmology Clinics, Ankara, Turkey
| | - Isao Noda
- The Procter and Gamble Company,West Chester, Ohio, USA
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