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Jain S, John A, George CE, Johnson RP. Tyrosine-Derived Polymers as Potential Biomaterials: Synthesis Strategies, Properties, and Applications. Biomacromolecules 2023; 24:531-565. [PMID: 36702743 DOI: 10.1021/acs.biomac.2c01232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Peptide-based polymers are evolving as promising materials for various biomedical applications. Among peptide-based polymers, polytyrosine (PTyr)-based and l-tyrosine (Tyr)-derived polymers are unique, due to their excellent biocompatibility, degradability, and functional as well as engineering properties. To date, different polymerization techniques (ring-opening polymerization, enzymatic polymerization, condensation polymerization, solution-interfacial polymerization, and electropolymerization) have been used to synthesize various PTyr-based and Tyr-derived polymers. Even though the synthesis starts from Tyr, different synthesis routes yield different polymers (polypeptides, polyarylates, polyurethanes, polycarbonates, polyiminocarbonate, and polyphosphates) with unique functional characteristics, and these polymers have been successfully used for various biomedical applications in the past decades. This Review comprehensively describes the synthesis approaches, classification, and properties of various PTyr-based and Tyr-derived polymers employed in drug delivery, tissue engineering, and biosensing applications.
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Affiliation(s)
- Supriya Jain
- Polymer Nanobiomaterial Research Laboratory, Nanoscience and Microfluidics Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, Karnataka 575018, India
| | - Alona John
- Polymer Nanobiomaterial Research Laboratory, Nanoscience and Microfluidics Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, Karnataka 575018, India
| | - Christina Elizhabeth George
- Polymer Nanobiomaterial Research Laboratory, Nanoscience and Microfluidics Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, Karnataka 575018, India
| | - Renjith P Johnson
- Polymer Nanobiomaterial Research Laboratory, Nanoscience and Microfluidics Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, Karnataka 575018, India
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Augmenting Peripheral Nerve Regeneration with Adipose-Derived Stem Cells. Stem Cell Rev Rep 2022; 18:544-558. [PMID: 34417730 PMCID: PMC8858329 DOI: 10.1007/s12015-021-10236-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2021] [Indexed: 02/03/2023]
Abstract
Peripheral nerve injuries (PNIs) are common and debilitating, cause significant health care costs for society, and rely predominately on autografts, which necessitate grafting a nerve section non-locally to repair the nerve injury. One possible approach to improving treatment is bolstering endogenous regenerative mechanisms or bioengineering new nervous tissue in the peripheral nervous system. In this review, we discuss critical-sized nerve gaps and nerve regeneration in rats, and summarize the roles of adipose-derived stem cells (ADSCs) in the treatment of PNIs. Several regenerative treatment modalities for PNI are described: ADSCs differentiating into Schwann cells (SCs), ADSCs secreting growth factors to promote peripheral nerve growth, ADSCs promoting myelination growth, and ADSCs treatments with scaffolds. ADSCs' roles in regenerative treatment and features are compared to mesenchymal stem cells, and the administration routes, cell dosages, and cell fates are discussed. ADSCs secrete neurotrophic factors and exosomes and can differentiate into Schwann cell-like cells (SCLCs) that share features with naturally occurring SCs, including the ability to promote nerve regeneration in the PNS. Future clinical applications are also discussed.
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Zhou X, Du J, Qing L, Mee T, Xu X, Wang Z, Xu C, Jia X. Identification of sensory and motor nerve fascicles by immunofluorescence staining after peripheral nerve injury. J Transl Med 2021; 19:207. [PMID: 33985539 PMCID: PMC8117274 DOI: 10.1186/s12967-021-02871-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 05/03/2021] [Indexed: 11/25/2022] Open
Abstract
Background Inappropriate matching of motor and sensory fibers after nerve repair or nerve grafting can lead to failure of nerve recovery. Identification of motor and sensory fibers is important for the development of new approaches that facilitate neural regeneration and the next generation of nerve signal-controlled neuro-prosthetic limbs with sensory feedback technology. Only a few methods have been reported to differentiate sensory and motor nerve fascicles, and the reliability of these techniques is unknown. Immunofluorescence staining is one of the most commonly used methods to distinguish sensory and motor nerve fibers, however, its accuracy remains unknown. Methods In this study, we aim to determine the efficacy of popular immunofluorescence markers for motor and sensory nerve fibers. We harvested the facial (primarily motor fascicles) and sural (primarily sensory fascicles) nerves in rats, and examined the immunofluorescent staining expressions of motor markers (choline acetyltransferase (ChAT), tyrosine kinase (TrkA)), and sensory markers [neurofilament protein 200 kDa (NF-200), calcitonin gene-related peptide (CGRP) and Transient receptor potential vanillic acid subtype 1 (TRPV1)]. Three methods, including the average area percentage, the mean gray value, and the axon count, were used to quantify the positive expression of nerve markers in the immunofluorescence images. Results Our results suggest the mean gray value method is the most reliable method. The mean gray value of immunofluorescence in ChAT (63.0 ± 0.76%) and TRKA (47.6 ± 0.43%) on the motor fascicles was significantly higher than that on the sensory fascicles (ChAT: 49.2 ± 0.72%, P < 0.001; and TRKA: 29.1 ± 0.85%, P < 0.001). Additionally, the mean gray values of TRPV1 (51.5 ± 0.83%), NF-200 (61.5 ± 0.62%) and CGRP (37.7 ± 1.22%) on the motor fascicles were significantly lower than that on the sensory fascicles respectively (71.9 ± 2.32%, 69.3 ± 0.46%, and 54.3 ± 1.04%) (P < 0.001). The most accurate cutpoint occurred using CHAT/CRCP ratio, where a value of 0.855 had 100% sensitivity and 100% specificity to identify motor and sensory nerve with an area under the ROC curve of 1.000 (P < 0.001). Conclusions A combination of ChAT and CGRP is suggested to distinguish motor and sensory nerve fibers.
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Affiliation(s)
- Xijie Zhou
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children'S Hospital of Wenzhou Medical University, Wenzhou, 325027, China.,Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Jian Du
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Liming Qing
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Thomas Mee
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Xiang Xu
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Zhuoran Wang
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Cynthia Xu
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA. .,Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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4
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Yang W, Gong Y, Li W. A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants. Front Bioeng Biotechnol 2020; 8:622923. [PMID: 33585422 PMCID: PMC7873964 DOI: 10.3389/fbioe.2020.622923] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/10/2020] [Indexed: 01/28/2023] Open
Abstract
To date, a wide variety of neural tissue implants have been developed for neurophysiology recording from living tissues. An ideal neural implant should minimize the damage to the tissue and perform reliably and accurately for long periods of time. Therefore, the materials utilized to fabricate the neural recording implants become a critical factor. The materials of these devices could be classified into two broad categories: electrode materials as well as packaging and substrate materials. In this review, inorganic (metals and semiconductors), organic (conducting polymers), and carbon-based (graphene and carbon nanostructures) electrode materials are reviewed individually in terms of various neural recording devices that are reported in recent years. Properties of these materials, including electrical properties, mechanical properties, stability, biodegradability/bioresorbability, biocompatibility, and optical properties, and their critical importance to neural recording quality and device capabilities, are discussed. For the packaging and substrate materials, different material properties are desired for the chronic implantation of devices in the complex environment of the body, such as biocompatibility and moisture and gas hermeticity. This review summarizes common solid and soft packaging materials used in a variety of neural interface electrode designs, as well as their packaging performances. Besides, several biopolymers typically applied over the electrode package to reinforce the mechanical rigidity of devices during insertion, or to reduce the immune response and inflammation at the device-tissue interfaces are highlighted. Finally, a benchmark analysis of the discussed materials and an outlook of the future research trends are concluded.
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Affiliation(s)
- Weiyang Yang
- Microtechnology Lab, Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, United States
| | - Yan Gong
- Microtechnology Lab, Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, United States
| | - Wen Li
- Microtechnology Lab, Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, United States
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Du J, Chen H, Zhou K, Jia X. Quantitative Multimodal Evaluation of Passaging Human Neural Crest Stem Cells for Peripheral Nerve Regeneration. Stem Cell Rev Rep 2018; 14:92-100. [PMID: 28780695 DOI: 10.1007/s12015-017-9758-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Peripheral nerve injury is a major burden to societies worldwide, however, current therapy options (e.g. autologous nerve grafts) are unable to produce satisfactory outcomes. Many studies have shown that stem cell transplantation holds great potential for peripheral nerve repair, and human neural crest stem cells (hNCSCs), which give rise to a variety of tissues in the peripheral nervous system, are particularly promising. NCSCs are one of the best candidates for clinical translation, however, to ensure the viability and quality of NCSCs for research and clinical use, the effect of in vitro cell passaging on therapeutic effects needs be evaluated given that passaging is required to expand NCSCs to meet the demands of transplantation in preclinical research and clinical trials. To date, no study has investigated the quality of NCSCs past the 5th passage in vivo. In this study, we employed a multimodal evaluation system to investigate changes in outcomes between transplantation with 5th (p5) and 6th passage (p6) NCSCs in a 15 mm rat sciatic nerve injury and repair model. Using CatWalk gait analysis, gastrocnemius muscle index, electrophysiology, immunohistochemistry, and histomorphometric analysis, we showed that p6 NCSCs demonstrated decreased cell survival, Schwann-cell differentiation, axonal growth, and functional outcomes compared to p5 NCSCs (all p < 0.05). In conclusion, p6 NCSCs showed significantly reduced therapeutic efficacy compared to p5 NCSCs for peripheral nerve regeneration.
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Affiliation(s)
- Jian Du
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 559, Baltimore, MD, 21201, USA
| | - Huanwen Chen
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 559, Baltimore, MD, 21201, USA
| | - Kailiang Zhou
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 559, Baltimore, MD, 21201, USA.,Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 559, Baltimore, MD, 21201, USA. .,Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, 325027, China. .,Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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6
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Du J, Zhen G, Chen H, Zhang S, Qing L, Yang X, Lee G, Mao HQ, Jia X. Optimal electrical stimulation boosts stem cell therapy in nerve regeneration. Biomaterials 2018; 181:347-359. [PMID: 30098570 PMCID: PMC6201278 DOI: 10.1016/j.biomaterials.2018.07.015] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/07/2018] [Accepted: 07/10/2018] [Indexed: 12/29/2022]
Abstract
Peripheral nerve injuries often lead to incomplete recovery and contribute to significant disability to approximately 360,000 people in the USA each year. Stem cell therapy holds significant promise for peripheral nerve regeneration, but maintenance of stem cell viability and differentiation potential in vivo are still major obstacles for translation. Using a made-in-house 96-well vertical electrical stimulation (ES) platform, we investigated the effects of different stimulating pulse frequency, duration and field direction on human neural crest stem cell (NCSC) differentiation. We observed dendritic morphology with enhanced neuronal differentiation for NCSCs cultured on cathodes subject to 20 Hz, 100μs pulse at a potential gradient of 200 mV/mm. We further evaluated the effect of a novel cell-based therapy featuring optimized pulsatile ES of NCSCs for in vivo transplantation following peripheral nerve regeneration. 15 mm critical-sized sciatic nerve injuries were generated with subsequent surgical repair in sixty athymic nude rats. Injured animals were randomly assigned into five groups (N = 12 per group): blank control, ES, NCSC, NCSC + ES, and autologous nerve graft. The optimized ES was applied immediately after surgical repair for 1 h in ES and NCSC + ES groups. Recovery was assessed by behavioral (CatWalk gait analysis), wet muscle-mass, histomorphometric, and immunohistochemical analyses at either 6 or 12 weeks after surgery (N = 6 per group). Gastrocnemius muscle wet mass measurements in ES + NCSC group were comparable to autologous nerve transplantation and significantly higher than other groups (p < 0.05). Quantitative histomorphometric analysis and catwalk gait analysis showed similar improvements by ES on NCSCs (p < 0.05). A higher number of viable NCSCs was shown via immunochemical analysis, with higher Schwann cell (SC) differentiation in the NCSC + ES group compared to the NCSC group (p < 0.05). Overall, ES on NCSC transplantation significantly enhanced nerve regeneration after injury and repair, and was comparable to autograft treatment. Thus, ES can be a potent alternative to biochemical and physical cues for modulating stem cell survival and differentiation. This novel cell-based intervention presents an effective and safe approach for improved outcomes after peripheral nerve repair.
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Affiliation(s)
- Jian Du
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Gehua Zhen
- Department of Orthopaedics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Huanwen Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Shuming Zhang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Materials Science and Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Liming Qing
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Xiuli Yang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Gabsang Lee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Hai-Quan Mao
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Materials Science and Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Department of Anatomy Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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7
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Li R, Li Y, Wu Y, Zhao Y, Chen H, Yuan Y, Xu K, Zhang H, Lu Y, Wang J, Li X, Jia X, Xiao J. Heparin-Poloxamer Thermosensitive Hydrogel Loaded with bFGF and NGF Enhances Peripheral Nerve Regeneration in Diabetic Rats. Biomaterials 2018; 168:24-37. [PMID: 29609091 PMCID: PMC5935004 DOI: 10.1016/j.biomaterials.2018.03.044] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/21/2018] [Accepted: 03/24/2018] [Indexed: 12/13/2022]
Abstract
Peripheral nerve injury (PNI) is a major burden to society with limited therapeutic options, and novel biomaterials have great potential for shifting the current paradigm of treatment. With a rising prevalence of chronic illnesses such as diabetes mellitus (DM), treatment of PNI is further complicated, and only few studies have proposed therapies suitable for peripheral nerve regeneration in DM. To provide a supportive environment to restore structure and/or function of nerves in DM, we developed a novel thermo-sensitive heparin-poloxamer (HP) hydrogel co-delivered with basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) in diabetic rats with sciatic nerve crush injury. The delivery vehicle not only had a good affinity for large amounts of growth factors (GFs), but also controlled their release in a steady fashion, preventing degradation in vitro. In vivo, compared with HP hydrogel alone or direct GFs administration, GFs-HP hydrogel treatment is more effective at facilitating Schwann cell (SC) proliferation, leading to an increased expression of nerve associated structural proteins, enhanced axonal regeneration and remyelination, and improved recovery of motor function (all p < 0.05). Our mechanistic investigation also revealed that these neuroprotective and neuroregenerative effects of the GFs-HP hydrogel may be associated with activations of phosphatidylinositol 3 kinase and protein kinase B (PI3K/Akt), janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3), and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways. Our work provides a promising therapy option for peripheral nerve regeneration in patients with DM.
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Affiliation(s)
- Rui Li
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Yiyang Li
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Yanqing Wu
- The Institute of Life Sciences, Wenzhou University, Wenzhou 325035, China
| | - Yingzheng Zhao
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Huanwen Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yuan Yuan
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Ke Xu
- The Institute of Life Sciences, Wenzhou University, Wenzhou 325035, China
| | - Hongyu Zhang
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Yingfeng Lu
- Department of Peripheral Neurosurgery, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Jian Wang
- Department of Peripheral Neurosurgery, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Xiaokun Li
- The Institute of Life Sciences, Wenzhou University, Wenzhou 325035, China
| | - Xiaofeng Jia
- Department of Neurosurgery, Orthopaedics, Anatomy Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biomedical Engineering, Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Jian Xiao
- Molecular Pharmacology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China.
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8
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Chen H, Du J, Zhang Y, Barnes K, Jia X. Establishing a reliable gait evaluation method for rodent studies. J Neurosci Methods 2017; 283:92-100. [PMID: 28351803 DOI: 10.1016/j.jneumeth.2017.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/27/2017] [Accepted: 03/23/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND CatWalk is one of the most popular tools for evaluating gait recovery in preclinical research, however, there is currently no consensus on which of the many gait parameters captured by CatWalk can reliably model recovery. There are conflicting interpretations of results, along with many common but seldom reported problems such as heel walking and poor compliance. NEW METHOD We developed a systematic manual classification method that overcomes common problems such as heel walking and poor compliance. By correcting automation errors and removing inconsistent gait cycles, we isolated stretches of recordings that are more reliable for analysis. Recovery outcome was also assessed by quantitative histomorphometric analysis of myelinated axons. RESULTS While 40-60% of runs were erroneously classified without manual intervention, we corrected all errors with our new method, and showed that Stand Time, Duty Cycle, and Swing Speed are able to track significant differences over time and between experimental groups (all p<0.05). The usability of print area and intensity parameters requires further validation beyond the capabilities of CatWalk. COMPARISON WITH EXISTING METHOD(S) There is currently no strategy that addresses problems such as heel walking and poor compliance, and therefore no standard set of parameters that researchers can rely on to report their findings. CONCLUSION Manual classification is a crucial step to generate reliable CatWalk data, and Stand Time, Duty Cycle, and Swing Speed are suitable parameters for evaluating gait recovery. Static parameters such as print area and intensity should be used with extreme caution.
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Affiliation(s)
- Huanwen Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jian Du
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yifan Zhang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kevin Barnes
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Developing and Evaluating a Flexible Wireless Microcoil Array Based Integrated Interface for Epidural Cortical Stimulation. Int J Mol Sci 2017; 18:ijms18020335. [PMID: 28165427 PMCID: PMC5343870 DOI: 10.3390/ijms18020335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/26/2017] [Accepted: 01/31/2017] [Indexed: 11/30/2022] Open
Abstract
Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC) technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats’ unilateral epidural space for electrical stimulation of the primary visual cortex (V1) while the evoked responses were recorded on the contralateral V1 using a needle electrode. The wireless implantable board output stable monophasic voltage stimuli. The amplitude of the monophasic voltage output could be adjusted by controlling the voltage of the transmitter circuit within a range of 5–20 V. In acute experiment, cortico-cortical evoked potential (CCEP) response was recorded on the contralateral V1. The amplitude of N2 in CCEP was modulated by adjusting the stimulation intensity of the wireless interface. These results demonstrated that a wireless interface based on a microcoil array can offer a valuable tool for researchers to explore electrical stimulation in research and the dura mater-electrode interface can effectively transmit electrical stimulation.
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Weintraub S, Shpigel T, Harris LG, Schuster R, Lewis EC, Lewitus DY. Astaxanthin-based polymers as new antimicrobial compounds. Polym Chem 2017. [DOI: 10.1039/c7py00663b] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we describe the development of a library of polyastaxanthin, new polyester compounds with significant antimicrobial activity.
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Affiliation(s)
- S. Weintraub
- Plastics and Polymer Engineering Department
- Shenkar – Engineering Art Design
- Ramat-Gan
- Israel
| | - T. Shpigel
- Plastics and Polymer Engineering Department
- Shenkar – Engineering Art Design
- Ramat-Gan
- Israel
| | - L. G. Harris
- Microbiology and Infectious Diseases
- Institute of Life Science
- Swansea University Medical School
- Swansea
- UK
| | - R. Schuster
- Department of Clinical Biochemistry and Pharmacology
- Faculty of Health Sciences
- Ben-Gurion University of the Negev
- Beer-Sheva
- Israel
| | - E. C. Lewis
- Department of Clinical Biochemistry and Pharmacology
- Faculty of Health Sciences
- Ben-Gurion University of the Negev
- Beer-Sheva
- Israel
| | - D. Y. Lewitus
- Plastics and Polymer Engineering Department
- Shenkar – Engineering Art Design
- Ramat-Gan
- Israel
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11
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Advances and Future Applications of Augmented Peripheral Nerve Regeneration. Int J Mol Sci 2016; 17:ijms17091494. [PMID: 27618010 PMCID: PMC5037771 DOI: 10.3390/ijms17091494] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/30/2016] [Accepted: 08/30/2016] [Indexed: 02/06/2023] Open
Abstract
Peripheral nerve injuries remain a significant source of long lasting morbidity, disability, and economic costs. Much research continues to be performed in areas related to improving the surgical outcomes of peripheral nerve repair. In this review, the physiology of peripheral nerve regeneration and the multitude of efforts to improve surgical outcomes are discussed. Improvements in tissue engineering that have allowed for the use of synthetic conduits seeded with neurotrophic factors are highlighted. Selected pre-clinical and available clinical data using cell based methods such as Schwann cell, undifferentiated, and differentiated stem cell transplantation to guide and enhance peripheral nerve regeneration are presented. The limitations that still exist in the utility of neurotrophic factors and cell-based therapies are outlined. Strategies that are most promising for translation into the clinical arena are suggested.
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12
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Bowen PK, Shearier ER, Zhao S, Guillory RJ, Zhao F, Goldman J, Drelich JW. Biodegradable Metals for Cardiovascular Stents: from Clinical Concerns to Recent Zn-Alloys. Adv Healthc Mater 2016; 5:1121-40. [PMID: 27094868 PMCID: PMC4904226 DOI: 10.1002/adhm.201501019] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/01/2016] [Indexed: 12/31/2022]
Abstract
Metallic stents are used to promote revascularization and maintain patency of plaqued or damaged arteries following balloon angioplasty. To mitigate the long-term side effects associated with corrosion-resistant stents (i.e., chronic inflammation and late stage thrombosis), a new generation of so-called "bioabsorbable" stents is currently being developed. The bioabsorbable coronary stents will corrode and be absorbed by the artery after completing their task as vascular scaffolding. Research spanning the last two decades has focused on biodegradable polymeric, iron-based, and magnesium-based stent materials. The inherent mechanical and surface properties of metals make them more attractive stent material candidates than their polymeric counterparts. A third class of metallic bioabsorbable materials that are based on zinc has been introduced in the last few years. This new zinc-based class of materials demonstrates the potential for an absorbable metallic stent with the mechanical and biodegradation characteristics required for optimal stent performance. This review compares bioabsorbable materials and summarizes progress towards bioabsorbable stents. It emphasizes the current understanding of physiological and biological benefits of zinc and its biocompatibility. Finally, the review provides an outlook on challenges in designing zinc-based stents of optimal mechanical properties and biodegradation rate.
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Affiliation(s)
- Patrick K Bowen
- Department of Materials Science and Engineering, Michigan Technological University, Houghton, MI, 49931
| | - Emily R Shearier
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, 49931
| | - Shan Zhao
- Department of Materials Science and Engineering, Michigan Technological University, Houghton, MI, 49931
| | - Roger J Guillory
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, 49931
| | - Feng Zhao
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, 49931
| | - Jeremy Goldman
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, 49931
| | - Jaroslaw W Drelich
- Department of Materials Science and Engineering, Michigan Technological University, Houghton, MI, 49931
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Clements BA, Bushman J, Murthy NS, Ezra M, Pastore CM, Kohn J. Design of barrier coatings on kink-resistant peripheral nerve conduits. J Tissue Eng 2016; 7:2041731416629471. [PMID: 26977288 PMCID: PMC4765812 DOI: 10.1177/2041731416629471] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/28/2015] [Indexed: 01/17/2023] Open
Abstract
Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1) electrospinning a layer of polymer fibers onto the surface of the conduit and (2) coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery.
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Affiliation(s)
- Basak Acan Clements
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Jared Bushman
- School of Pharmacy, University of Wyoming, Laramie, WY, USA
| | - N Sanjeeva Murthy
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Mindy Ezra
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Christopher M Pastore
- Kanbar College of Design, Engineering and Commerce, Philadelphia University, Philadelphia, PA, USA
| | - Joachim Kohn
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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Johnson BN, Jia X. 3D printed nerve guidance channels: computer-aided control of geometry, physical cues, biological supplements and gradients. Neural Regen Res 2016; 11:1568-1569. [PMID: 27904481 PMCID: PMC5116829 DOI: 10.4103/1673-5374.193230] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Affiliation(s)
- Blake N Johnson
- Department of Industrial and Systems Engineering, School of Neuroscience, Virginia Tech, Blacksburg, VA, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, Orthopaedics, Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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15
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Johnson BN, Lancaster KZ, Zhen G, He J, Gupta MK, Kong YL, Engel EA, Krick KD, Ju A, Meng F, Enquist LW, Jia X, McAlpine MC. 3D Printed Anatomical Nerve Regeneration Pathways. ADVANCED FUNCTIONAL MATERIALS 2015; 25:6205-6217. [PMID: 26924958 PMCID: PMC4765385 DOI: 10.1002/adfm.201501760] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
An imaging-coupled 3D printing methodology for the design, optimization, and fabrication of a customized nerve repair technology for complex injuries is presented. The custom scaffolds are deterministically fabricated via a microextrusion printing principle which enables the simultaneous incorporation of anatomical geometries, biomimetic physical cues, and spatially controlled biochemical gradients in a one-pot 3D manufacturing approach.
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Affiliation(s)
- Blake N. Johnson
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States, Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Karen Z. Lancaster
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Gehua Zhen
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Junyun He
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Maneesh K. Gupta
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Yong Lin Kong
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Esteban A. Engel
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Kellin D. Krick
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Alex Ju
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Fanben Meng
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Lynn W. Enquist
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Xiaofeng Jia
- Department of Neurosurgery, Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States, Department of Biomedical Engineering, Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Michael C. McAlpine
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States, Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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16
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Jorfi M, Skousen JL, Weder C, Capadona JR. Progress towards biocompatible intracortical microelectrodes for neural interfacing applications. J Neural Eng 2014; 12:011001. [PMID: 25460808 DOI: 10.1088/1741-2560/12/1/011001] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To ensure long-term consistent neural recordings, next-generation intracortical microelectrodes are being developed with an increased emphasis on reducing the neuro-inflammatory response. The increased emphasis stems from the improved understanding of the multifaceted role that inflammation may play in disrupting both biologic and abiologic components of the overall neural interface circuit. To combat neuro-inflammation and improve recording quality, the field is actively progressing from traditional inorganic materials towards approaches that either minimizes the microelectrode footprint or that incorporate compliant materials, bioactive molecules, conducting polymers or nanomaterials. However, the immune-privileged cortical tissue introduces an added complexity compared to other biomedical applications that remains to be fully understood. This review provides a comprehensive reflection on the current understanding of the key failure modes that may impact intracortical microelectrode performance. In addition, a detailed overview of the current status of various materials-based approaches that have gained interest for neural interfacing applications is presented, and key challenges that remain to be overcome are discussed. Finally, we present our vision on the future directions of materials-based treatments to improve intracortical microelectrodes for neural interfacing.
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Affiliation(s)
- Mehdi Jorfi
- Adolphe Merkle Institute, University of Fribourg, Rte de l'Ancienne Papeterie, CH-1723 Marly, Switzerland
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17
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Khaled I, Elmallah S, Cheng C, Moussa WA, Mushahwar VK, Elias AL. A flexible base electrode array for intraspinal microstimulation. IEEE Trans Biomed Eng 2013; 60:2904-13. [PMID: 23744656 DOI: 10.1109/tbme.2013.2265877] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this paper, we report the development of a flexible base array of penetrating electrodes which can be used to interface with the spinal cord. A customizable and feasible fabrication protocol is described. The flexible base arrays were fabricated and implanted into surrogate cords which were elongated by 12%. The resulting strains were optically measured across the cord and compared to those associated with two types of electrodes arrays (one without a base and one with a rigid base connecting the electrodes). The deformation behavior of cords implanted with the flexible base arrays resembled the behavior of cords implanted with individual microwires that were not connected through a base. The results of the strain test were used to validate a 2-D finite element model. The validated model was used to assess the stresses induced by the electrodes of the three types of arrays on the cord, and to examine how various design parameters (thickness, base modulus, etc.,) impact the mechanical behavior of the electrode array. Rigid base arrays induced higher stresses on the cord than the flexible base arrays which in turn imposed higher stresses than the individual microwire implants. The developed flexible base array showed improvement over the rigid base array; however, its stiffness needs to be further reduced to emulate the mechanical behavior of individual microwire arrays without a base.
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18
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Clements IP, Mukhatyar VJ, Srinivasan A, Bentley JT, Andreasen DS, Bellamkonda RV. Regenerative scaffold electrodes for peripheral nerve interfacing. IEEE Trans Neural Syst Rehabil Eng 2012; 21:554-66. [PMID: 23033438 DOI: 10.1109/tnsre.2012.2217352] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Advances in neural interfacing technology are required to enable natural, thought-driven control of a prosthetic limb. Here, we describe a regenerative electrode design in which a polymer-based thin-film electrode array is integrated within a thin-film sheet of aligned nanofibers, such that axons regenerating from a transected peripheral nerve are topographically guided across the electrode recording sites. Cultures of dorsal root ganglia were used to explore design parameters leading to cellular migration and neurite extension across the nanofiber/electrode array boundary. Regenerative scaffold electrodes (RSEs) were subsequently fabricated and implanted across rat tibial nerve gaps to evaluate device recording capabilities and influence on nerve regeneration. In 20 of these animals, regeneration was compared between a conventional nerve gap model and an amputation model. Characteristic shaping of regenerated nerve morphology around the embedded electrode array was observed in both groups, and regenerated axon profile counts were similar at the eight week end point. Implanted RSEs recorded evoked neural activity in all of these cases, and also in separate implantations lasting up to five months. These results demonstrate that nanofiber-based topographic cues within a regenerative electrode can influence nerve regeneration, to the potential benefit of a peripheral nerve interface suitable for limb amputees.
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Affiliation(s)
- Isaac P Clements
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA.
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19
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Macri LK, Sheihet L, Singer AJ, Kohn J, Clark RA. Ultrafast and fast bioerodible electrospun fiber mats for topical delivery of a hydrophilic peptide. J Control Release 2012; 161:813-20. [DOI: 10.1016/j.jconrel.2012.04.035] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/17/2012] [Accepted: 04/22/2012] [Indexed: 11/16/2022]
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20
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Khan W, Muthupandian S, Farah S, Kumar N, Domb AJ. Biodegradable Polymers Derived From Amino Acids. Macromol Biosci 2011; 11:1625-36. [DOI: 10.1002/mabi.201100324] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 09/11/2011] [Indexed: 01/17/2023]
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21
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Lewitus DY, Smith KL, Shain W, Bolikal D, Kohn J. The fate of ultrafast degrading polymeric implants in the brain. Biomaterials 2011; 32:5543-50. [PMID: 21609850 DOI: 10.1016/j.biomaterials.2011.04.052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 04/20/2011] [Indexed: 12/30/2022]
Abstract
We have recently reported on an ultrafast degrading tyrosine-derived terpolymer that degrades and resorbs within hours, and is suitable for use in cortical neural prosthetic applications. Here we further characterize this polymer, and describe a new tyrosine-derived fast degrading terpolymer in which the poly(ethylene glycol) (PEG) is replaced by poly(trimethylene carbonate) (PTMC). This PTMC containing terpolymer showed similar degradation characteristics but its resorption was negligible in the same period. Thus, changes in the polymer chemistry allowed for the development of two ultrafast degrading polymers with distinct difference in resorption properties. The in vivo tissue response to both polymers used as intraparenchymal cortical devices was compared to poly(lactic-co-glycolic acid) (PLGA). Slow resorbing, indwelling implant resulted in continuous glial activation and loss of neural tissue. In contrast, the fast degrading tyrosine-derived terpolymer that is also fast resorbing, significantly reduced both the glial response in the implantation site and the neuronal exclusion zone. Such polymers allow for brain tissue recovery, thus render them suitable for neural interfacing applications.
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Affiliation(s)
- Dan Y Lewitus
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, 145 Bevier Rd., Piscataway, NJ 08854, USA.
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