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Wei H, Chen Z, Hu Y, Cao W, Ma X, Zhang C, Gao X, Qian X, Zhao Y, Chai R. Topographically Conductive Butterfly Wing Substrates for Directed Spiral Ganglion Neuron Growth. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2102062. [PMID: 34411420 DOI: 10.1002/smll.202102062] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Spiral ganglion neuron (SGN) degeneration can lead to severe hearing loss, and the directional regeneration of SGNs has shown great potential for improving the efficacy of auditory therapy. Here, a novel 3D conductive microstructure with surface topologies is presented by integrating superaligned carbon-nanotube sheets (SA-CNTs) onto Morpho Menelaus butterfly wings for SGN culture. The parallel groove-like topological structures of M. Menelaus wings induce the cultured cells to grow along the direction of its ridges. The excellent conductivity of SA-CNTs significantly improves the efficiency of cellular information conduction. When integrating the SA-CNTs with M. Menelaus wings, the SA-CNTs are aligned in parallel with the M. Menelaus ridges, which further strengthens the consistency of the surface topography in the composite substrate. The SA-CNTs integrated onto butterfly wings provide powerful physical signals and regulate the behavior of SGNs, including cell survival, adhesion, neurite outgrowth, and synapse formation. These features indicate the possibility of directed regeneration after auditory nerve injury.
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Affiliation(s)
- Hao Wei
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline, Nanjing, 210008, China
| | - Zhuoyue Chen
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Yangnan Hu
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Wei Cao
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, 230601, China
| | - XiaoFeng Ma
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline, Nanjing, 210008, China
| | - Chen Zhang
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, 100069, China
| | - Xia Gao
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline, Nanjing, 210008, China
| | - Xiaoyun Qian
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline, Nanjing, 210008, China
| | - Yuanjin Zhao
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline, Nanjing, 210008, China
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Renjie Chai
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline, Nanjing, 210008, China
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, 100069, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China
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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.
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Photopolymerized Microfeatures Guide Adult Spiral Ganglion and Dorsal Root Ganglion Neurite Growth. Otol Neurotol 2018; 39:119-126. [PMID: 29227456 DOI: 10.1097/mao.0000000000001622] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
HYPOTHESIS Microtopographical patterns generated by photopolymerization of methacrylate polymer systems will direct growth of neurites from adult neurons, including spiral ganglion neurons (SGNs). BACKGROUND Cochlear implants (CIs) provide hearing perception to patients with severe to profound hearing loss. However, their ability to encode complex auditory stimuli is limited due, in part, to poor spatial resolution caused by spread of the electrical currents in the inner ear. Directing the regrowth of SGN peripheral processes towards stimulating electrodes could help reduce current spread and improve spatial resolution provided by the CI. Previous work has demonstrated that micro- and nano-scale patterned surfaces precisely guide the growth of neurites from a variety of neonatal neurons including SGNs. Here, we sought to determine the extent to which adult neurons likewise respond to these topographical surface features. METHODS Photopolymerization was used to fabricate methacrylate polymer substrates with micropatterned surfaces of varying amplitudes and periodicities. Dissociated adult dorsal root ganglion neurons (DRGNs) and SGNs were cultured on these surfaces and the alignment of the neurite processes to the micropatterns was determined. RESULTS Neurites from both adult DRGNs and SGNs significantly aligned to the patterned surfaces similar to their neonatal counterparts. Further DRGN and SGN neurite alignment increased as the amplitude of the microfeatures increased. Decreased pattern periodicity also improved neurite alignment. CONCLUSION Microscale surface topographic features direct the growth of adult SGN neurites. Topographical features could prove useful for guiding growth of SGN peripheral axons towards a CI electrode array.
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Albisetti E, Carroll KM, Lu X, Curtis JE, Petti D, Bertacco R, Riedo E. Thermochemical scanning probe lithography of protein gradients at the nanoscale. NANOTECHNOLOGY 2016; 27:315302. [PMID: 27344982 DOI: 10.1088/0957-4484/27/31/315302] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Patterning nanoscale protein gradients is crucial for studying a variety of cellular processes in vitro. Despite the recent development in nano-fabrication technology, combining nanometric resolution and fine control of protein concentrations is still an open challenge. Here, we demonstrate the use of thermochemical scanning probe lithography (tc-SPL) for defining micro- and nano-sized patterns with precisely controlled protein concentration. First, tc-SPL is performed by scanning a heatable atomic force microscopy tip on a polymeric substrate, for locally exposing reactive amino groups on the surface, then the substrate is functionalized with streptavidin and laminin proteins. We show, by fluorescence microscopy on the patterned gradients, that it is possible to precisely tune the concentration of the immobilized proteins by varying the patterning parameters during tc-SPL. This paves the way to the use of tc-SPL for defining protein gradients at the nanoscale, to be used as chemical cues e.g. for studying and regulating cellular processes in vitro.
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Affiliation(s)
- E Albisetti
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy. School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Tuft BW, Zhang L, Xu L, Hangartner A, Leigh B, Hansen MR, Guymon CA. Material stiffness effects on neurite alignment to photopolymerized micropatterns. Biomacromolecules 2014; 15:3717-27. [PMID: 25211120 PMCID: PMC4195519 DOI: 10.1021/bm501019s] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ability to direct neurite growth into a close proximity of stimulating elements of a neural prosthesis, such as a retinal or cochlear implant (CI), may enhance device performance and overcome current spatial signal resolution barriers. In this work, spiral ganglion neurons (SGNs), which are the target neurons to be stimulated by CIs, were cultured on photopolymerized micropatterns with varied matrix stiffnesses to determine the effect of rigidity on neurite alignment to physical cues. Micropatterns were generated on methacrylate thin film surfaces in a simple, rapid photopolymerization step by photomasking the prepolymer formulation with parallel line-space gratings. Two methacrylate series, a nonpolar HMA-co-HDDMA series and a polar PEGDMA-co-EGDMA series, with significantly different surface wetting properties were evaluated. Equivalent pattern periodicity was maintained across each methacrylate series based on photomask band spacing, and the feature amplitude was tuned to a depth of 2 μm amplitude for all compositions using the temporal control afforded by the UV curing methodology. The surface morphology was characterized by scanning electron microscopy and white light interferometry. All micropatterned films adsorb similar amounts of laminin from solution, and no significant difference in SGN survival was observed when the substrate compositions were compared. SGN neurite alignment significantly increases with increasing material modulus for both methacrylate series. Interestingly, SGN neurites respond to material stiffness cues that are orders of magnitude higher (GPa) than what is typically ascribed to neural environments (kPa). The ability to understand neurite response to engineered physical cues and mechanical properties such as matrix stiffness will allow the development of advanced biomaterials that direct de novo neurite growth to address the spatial signal resolution limitations of current neural prosthetics.
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Affiliation(s)
- Bradley W Tuft
- Department of Chemical and Biochemical Engineering, University of Iowa , Iowa City, Iowa 52242, United States
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Tuft BW, Xu L, White SP, Seline AE, Erwood AM, Hansen MR, Guymon CA. Neural pathfinding on uni- and multidirectional photopolymerized micropatterns. ACS APPLIED MATERIALS & INTERFACES 2014; 6:11265-76. [PMID: 24911660 PMCID: PMC4215840 DOI: 10.1021/am501622a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 06/09/2014] [Indexed: 05/22/2023]
Abstract
Overcoming signal resolution barriers of neural prostheses, such as the commercially available cochlear impant (CI) or the developing retinal implant, will likely require spatial control of regenerative neural elements. To rationally design materials that direct nerve growth, it is first necessary to determine pathfinding behavior of de novo neurite growth from prosthesis-relevant cells such as spiral ganglion neurons (SGNs) in the inner ear. Accordingly, in this work, repeating 90° turns were fabricated as multidirectional micropatterns to determine SGN neurite turning capability and pathfinding. Unidirectional micropatterns and unpatterned substrates are used as comparisons. Spiral ganglion Schwann cell alignment (SGSC) is also examined on each surface type. Micropatterns are fabricated using the spatial reaction control inherent to photopolymerization with photomasks that have either parallel line spacing gratings for unidirectional patterns or repeating 90° angle steps for multidirectional patterns. Feature depth is controlled by modulating UV exposure time by shuttering the light source at given time increments. Substrate topography is characterized by white light interferometry and scanning electron microscopy (SEM). Both pattern types exhibit features that are 25 μm in width and 7.4 ± 0.7 μm in depth. SGN neurites orient randomly on unpatterned photopolymer controls, align and consistently track unidirectional patterns, and are substantially influenced by, but do not consistently track, multidirectional turning cues. Neurite lengths are 20% shorter on multidirectional substrates compared to unidirectional patterns while neurite branching and microfeature crossing events are significantly higher. For both pattern types, the majority of the neurite length is located in depressed surface features. Developing methods to understand neural pathfinding and to guide de novo neurite growth to specific stimulatory elements will enable design of innovative biomaterials that improve functional outcomes of devices that interface with the nervous system.
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Affiliation(s)
- Bradley W. Tuft
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242,
United States, United States
| | - Linjing Xu
- Department
of Otolaryngology, University of Iowa Hospitals
and Clinics, Iowa City, Iowa 52242, United States, United States
| | - Scott P. White
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242,
United States, United States
| | - Alison E. Seline
- Department
of Otolaryngology, University of Iowa Hospitals
and Clinics, Iowa City, Iowa 52242, United States, United States
| | - Andrew M. Erwood
- Department
of Otolaryngology, University of Iowa Hospitals
and Clinics, Iowa City, Iowa 52242, United States, United States
| | - Marlan R. Hansen
- Department
of Otolaryngology, University of Iowa Hospitals
and Clinics, Iowa City, Iowa 52242, United States, United States
| | - C. Allan Guymon
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242,
United States, United States
- Tel.:(319)335-5015
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7
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Abstract
The precise wiring of the nervous system relies on processes by which axons navigate in a complex environment and are guided by a concerted action of attractive and repulsive factors to reach their target. Investigating these guidance processes depends critically on our ability to control in space and time the microenvironment of neurons. The implementation of microfabrication techniques in cell biology now enables a precise control of the extracellular physical and chemical environment of cultured cells. However, microtechnology is only beginning to be applied in the field of axon guidance due to specific requirements of neuronal cultures. Here we review microdevices specifically designed to study axonal guidance and compare them with the conventional assays used to probe gradient sensing in cell biology. We also discuss how innovative microdevice-based approaches will enable the investigation of important systems-level questions on the gradient sensing properties of nerve cells, such as the sensitivity and robustness in the detection of directional signals or the combinatorial response to multiple cues.
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Edwards D, Stancescu M, Molnar P, Hickman JJ. Two cell circuits of oriented adult hippocampal neurons on self-assembled monolayers for use in the study of neuronal communication in a defined system. ACS Chem Neurosci 2013; 4:1174-82. [PMID: 23611164 PMCID: PMC3750684 DOI: 10.1021/cn300206k] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 04/23/2013] [Indexed: 11/29/2022] Open
Abstract
In this study, we demonstrate the directed formation of small circuits of electrically active, synaptically connected neurons derived from the hippocampus of adult rats through the use of engineered chemically modified culture surfaces that orient the polarity of the neuronal processes. Although synaptogenesis, synaptic communication, synaptic plasticity, and brain disease pathophysiology can be studied using brain slice or dissociated embryonic neuronal culture systems, the complex elements found in neuronal synapses makes specific studies difficult in these random cultures. The study of synaptic transmission in mature adult neurons and factors affecting synaptic transmission are generally studied in organotypic cultures, in brain slices, or in vivo. However, engineered neuronal networks would allow these studies to be performed instead on simple functional neuronal circuits derived from adult brain tissue. Photolithographic patterned self-assembled monolayers (SAMs) were used to create the two-cell "bidirectional polarity" circuit patterns. This pattern consisted of a cell permissive SAM, N-1[3-(trimethoxysilyl)propyl] diethylenetriamine (DETA), and was composed of two 25 μm somal adhesion sites connected with 5 μm lines acting as surface cues for guided axonal and dendritic regeneration. Surrounding the DETA pattern was a background of a non-cell-permissive poly(ethylene glycol) (PEG) SAM. Adult hippocampal neurons were first cultured on coverslips coated with DETA monolayers and were later passaged onto the PEG-DETA bidirectional polarity patterns in serum-free medium. These neurons followed surface cues, attaching and regenerating only along the DETA substrate to form small engineered neuronal circuits. These circuits were stable for more than 21 days in vitro (DIV), during which synaptic connectivity was evaluated using basic electrophysiological methods.
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Affiliation(s)
- Darin Edwards
- Nanoscience Technology
Center, University of Central Florida,
12424 United States
Research Parkway, Suite 400, Orlando, Florida 32826, United States
- Biomedical Sciences, University of Central Florida, 6900 Lake Nona Boulevard,
Orlando, Florida 32827, United States
| | - Maria Stancescu
- Nanoscience Technology
Center, University of Central Florida,
12424 United States
Research Parkway, Suite 400, Orlando, Florida 32826, United States
| | - Peter Molnar
- Nanoscience Technology
Center, University of Central Florida,
12424 United States
Research Parkway, Suite 400, Orlando, Florida 32826, United States
- Department of Zoology, University of West Hungary, Szombathely H-9700, Hungary
| | - James J. Hickman
- Nanoscience Technology
Center, University of Central Florida,
12424 United States
Research Parkway, Suite 400, Orlando, Florida 32826, United States
- Biomedical Sciences, University of Central Florida, 6900 Lake Nona Boulevard,
Orlando, Florida 32827, United States
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Cheng N, Cao X. Neuron-like PC12 cell patterning on a photoactive self-assembled monolayer. J Biomed Mater Res A 2013; 101:3066-75. [DOI: 10.1002/jbm.a.34615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 01/18/2013] [Accepted: 01/22/2013] [Indexed: 12/19/2022]
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10
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Photopolymerized microfeatures for directed spiral ganglion neurite and Schwann cell growth. Biomaterials 2012; 34:42-54. [PMID: 23069708 DOI: 10.1016/j.biomaterials.2012.09.053] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/23/2012] [Indexed: 12/15/2022]
Abstract
Cochlear implants (CIs) provide auditory perception to individuals with severe hearing impairment. However, their ability to encode complex auditory stimuli is limited due, in part, to poor spatial resolution caused by electrical current spread in the inner ear. Directing nerve cell processes towards target electrodes may reduce the problematic current spread and improve stimulatory specificity. In this work, photopolymerization was used to fabricate micro- and nano-patterned methacrylate polymers to probe the extent of spiral ganglion neuron (SGN) neurite and Schwann cell (SGSC) contact guidance based on variations in substrate topographical cues. Micropatterned substrates are formed in a rapid, single-step reaction by selectively blocking light with photomasks which have parallel line-space gratings with periodicities of 10-100 μm. Channel amplitudes of 250 nm-10 μm are generated by modulating UV exposure time, light intensity, and photoinitiator concentration. Gradual transitions are observed between ridges and grooves using scanning electron and atomic force microscopy. The transitions stand in contrast to vertical features generated via etching lithographic techniques. Alignment of neural elements increases significantly with increasing feature amplitude and constant periodicity, as well as with decreasing periodicity and constant amplitude. SGN neurite alignment strongly correlates (r = 0.93) with maximum feature slope. Multiple neuronal and glial types orient to the patterns with varying degrees of alignment. This work presents a method to fabricate gradually-sloping micropatterns for cellular contact guidance studies and demonstrates spatial control of inner ear neural elements in response to micro- and nano-scale surface topography.
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Lee TH, Pan H, Kim IS, Kim JK, Cho TH, Oh JH, Yoon YB, Lee JH, Hwang SJ, Kim SJ. Functional regeneration of a severed peripheral nerve with a 7-mm gap in rats through the use of an implantable electrical stimulator and a conduit electrode with collagen coating. Neuromodulation 2012; 13:299-304; discussion 305. [PMID: 21992887 DOI: 10.1111/j.1525-1403.2010.00296.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This paper examined the efficacy of an implantable electrical stimulator in rats for the functional regeneration of peripheral nerves. MATERIALS AND METHODS The implantable electrical stimulator was fabricated on a polyimide-based conduit with an integrated electrode, a stimulation chip, and a battery; 3 mg/mL of collagen gel was coated onto the conduit surface and electrical stimulation (20 µ A, 100 µ s, and 100 Hz biphasic current) was continuously applied between the nerve stumps for four weeks. The stimulator was tested on a severed sciatic nerve with a 7-mm gap in rats. The effects of both the electrical stimulation and the collagen application were examined. RESULTS Functionality was evaluated through walk track assessments and by recording the action potential of the regenerated nerve. Immunohistochemical staining of the regenerated nerve was done using peripheral myelin protein 22. CONCLUSION The results suggest that the functional recovery of a severed peripheral nerve by the proposed implantable electrical stimulator was achieved through electrical current stimulation along the use of a collagen coating on the conduit surface.
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Affiliation(s)
- Tae Hyung Lee
- School of Electrical Engineering and Computer Science, Seoul National University, Seoul, Korea
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12
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Elele E, Shen Y, Susarla R, Khusid B, Keyvan G, Michniak-Kohn B. Electrodeless Electrohydrodynamic Drop-on-Demand Encapsulation of Drugs into Porous Polymer Films for Fabrication of Personalized Dosage Units. J Pharm Sci 2012; 101:2523-33. [DOI: 10.1002/jps.23165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 03/26/2012] [Accepted: 04/04/2012] [Indexed: 11/11/2022]
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Weng B, Liu X, Higgins MJ, Shepherd R, Wallace G. Fabrication and characterization of cytocompatible polypyrrole films inkjet printed from nanoformulations cytocompatible, inkjet-printed polypyrrole films. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:3434-3438. [PMID: 21972116 DOI: 10.1002/smll.201101491] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Indexed: 05/31/2023]
Abstract
Inkjet printed polypyrrole (PPy) films with good uniformity and conductivity are fabricated from a stable, printable PPy nanodispersion, and the cytocompatability of these platforms is demonstrated using PC12 cells. This novel approach to fabricating PPy electrodes and films for tissue engineering and cell stimulation is particularly useful where microstructures are required.
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Affiliation(s)
- Bo Weng
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
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Yamazoe H. Fabrication of protein micropatterns using a functional substrate with convertible protein-adsorption surface properties. J Biomed Mater Res A 2011; 100:362-9. [DOI: 10.1002/jbm.a.33279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 09/01/2011] [Accepted: 09/14/2011] [Indexed: 11/08/2022]
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15
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Clarke JC, Tuft BW, Clinger JD, Levine R, Figueroa LS, Guymon CA, Hansen MR. Micropatterned methacrylate polymers direct spiral ganglion neurite and Schwann cell growth. Hear Res 2011; 278:96-105. [PMID: 21616131 DOI: 10.1016/j.heares.2011.05.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 04/27/2011] [Accepted: 05/03/2011] [Indexed: 01/17/2023]
Abstract
Significant advances in the functional outcomes achieved with cochlear implantation will likely require tissue-engineering approaches to improve the neural prosthesis interface. One strategy is to direct spiral ganglion neuron (SGN) axon growth in a highly organized fashion to approximate or contact stimulating electrodes. Here we assessed the ability of micropatterns induced by photopolymerization in methacrylate (MA) polymer systems to direct cultured neonatal rat SGN neurite growth and alignment of SG Schwann cells (SGSCs). SGN survival and neurite length were comparable among various polymer compositions. Remarkably, there was no significant difference in SGN survival or neurite length between laminin and non-laminin coated MA polymer substrates, suggesting high biocompatibility with SG tissue. Micropatterning with photopolymerization generated microchannels with a ridge periodicity of 50 μm and channel depths of 0.6-1.0 μm. SGN neurites grew within the grooves of the microchannels. These topographies strongly induced alignment of dissociated SGN neurites and SGSCs to parallel the pattern. By contrast, fibroblasts failed to align with the micropattern suggesting cell specific responses to topographical cues. SGN neurites extending from explants turned to parallel the pattern as they encountered the microchannels. The extent of turning was significantly correlated with angle at which the neurite initially encountered the pattern. These results indicate that SGN neurites respond to microtopographical features and that these features can be used to direct neurite growth in a highly organized fashion.
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Affiliation(s)
- Joseph C Clarke
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, 2PFP, 200 Hawkins Dr., Iowa City, IA 52242, USA
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Kanje M, Johansson F. Nanomodified surfaces and neurite outgrowth. BRAIN MACHINE INTERFACES: IMPLICATIONS FOR SCIENCE, CLINICAL PRACTICE AND SOCIETY 2011; 194:253-62. [DOI: 10.1016/b978-0-444-53815-4.00002-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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17
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Cell guidance by magnetic nanowires. Exp Cell Res 2010; 316:688-94. [DOI: 10.1016/j.yexcr.2009.12.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 11/12/2009] [Accepted: 12/16/2009] [Indexed: 11/20/2022]
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18
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Ghibaudo M, Trichet L, Le Digabel J, Richert A, Hersen P, Ladoux B. Substrate topography induces a crossover from 2D to 3D behavior in fibroblast migration. Biophys J 2009; 97:357-68. [PMID: 19580774 PMCID: PMC2711370 DOI: 10.1016/j.bpj.2009.04.024] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 04/07/2009] [Accepted: 04/15/2009] [Indexed: 12/11/2022] Open
Abstract
In a three-dimensional environment, cells migrate through complex topographical features. Using microstructured substrates, we investigate the role of substrate topography in cell adhesion and migration. To do so, fibroblasts are plated on chemically identical substrates composed of microfabricated pillars. When the dimensions of the pillars (i.e., the diameter, length, and spacing) are varied, migrating cells encounter alternating flat and rough surfaces that depend on the spacing between the pillars. Consequently, we show that substrate topography affects cell shape and migration by modifying cell-to-substrate interactions. Cells on micropillar substrates exhibit more elongated and branched shapes with fewer actin stress fibers compared with cells on flat surfaces. By analyzing the migration paths in various environments, we observe different mechanisms of cell migration, including a persistent type of migration, that depend on the organization of the topographical features. These responses can be attributed to a spatial reorganization of the actin cytoskeleton due to physical constraints and a preferential formation of focal adhesions on the micropillars, with an increased lifetime compared to that observed on flat surfaces. By changing myosin II activity, we show that actomyosin contractility is essential in the cellular response to micron-scale topographic signals. Finally, the analysis of cell movements at the frontier between flat and micropillar substrates shows that cell transmigration through the micropillar substrates depends on the spacing between the pillars.
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Affiliation(s)
| | | | | | | | | | - Benoît Ladoux
- Laboratoire Matière et Systèmes Complexes (MSC), Université Paris Diderot and Centre National de la Recherche Scientifique, Unite Mixte de Recherche 7057, Paris, France
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Hällström W, Prinz CN, Suyatin D, Samuelson L, Montelius L, Kanje M. Rectifying and sorting of regenerating axons by free-standing nanowire patterns: a highway for nerve fibers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:4343-4346. [PMID: 19296620 DOI: 10.1021/la900436e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present an EBL-defined nanowire pattern that can sort axons coming from different directions on a substrate. The pattern defines tracks for left-bound traffic and right-bound traffic, which opens up new possibilities for designing neural networks on a chip.
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Affiliation(s)
- Waldemar Hällström
- Division of Solid State Physics, Department of Cell and Organism Biology, Lund University, Lund, Sweden
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20
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Nanomaterials for Neural Interfaces: Emerging New Function and Potential Applications. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/978-0-387-09459-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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21
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22
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Prinz C, Hällström W, Mårtensson T, Samuelson L, Montelius L, Kanje M. Axonal guidance on patterned free-standing nanowire surfaces. NANOTECHNOLOGY 2008; 19:345101. [PMID: 21730638 DOI: 10.1088/0957-4484/19/34/345101] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We demonstrate high-fidelity guidance of axons using rows of nanowires. The axons are prevented from crossing the rows, making it possible to guide and sort a large number of axons as opposed to when chemical patterns are used. Focal adhesion forms at the nanowires establishing a possible site of information transfer between the surface and the cells. Rows of gallium phosphide (GaP) nanowires were epitaxially grown on GaP(111) substrates in patterns defined by electron beam lithography.
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23
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Tzvetkova-Chevolleau T, Stéphanou A, Fuard D, Ohayon J, Schiavone P, Tracqui P. The motility of normal and cancer cells in response to the combined influence of the substrate rigidity and anisotropic microstructure. Biomaterials 2008; 29:1541-51. [DOI: 10.1016/j.biomaterials.2007.12.016] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 12/11/2007] [Indexed: 01/25/2023]
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Taylor M, Urquhart AJ, Zelzer M, Davies MC, Alexander MR. Picoliter water contact angle measurement on polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:6875-8. [PMID: 17503858 DOI: 10.1021/la070100j] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Water contact angle measurement is the most common method for determining a material's wettability, and the sessile drop approach is the most frequently used. However, the method is generally limited to macroscopic measurements because the base diameter of the droplet is usually greater than 1 mm. Here we report for the first time on a dosing system to dispense smaller individual droplets with control of the position and investigate whether water contact angles determined from picoliter volume water droplets are comparable with those obtained from the conventional microliter volume water droplets. This investigation was conducted on a group of commonly used polymers. To demonstrate the higher spatial resolution of wettability that can be achieved using picoliter volume water droplets, the wettability of a radial plasma polymer gradient was mapped using a 250 microm interval grid.
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Affiliation(s)
- Michael Taylor
- Laboratory of Biophysics and Surface Analysis, Department of Pharmaceutical Sciences, University of Nottingham, University Park, Nottingham, U.K
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