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Yang M, Cai X, Wang C, Li P, Chen S, Liu C, Wang Y, Qian K, Dong Q, Xue F, Chu C, Bai J, Liu Q, Ni X. Humidity-Responsive Amorphous Calcium-Magnesium Pyrophosphate/Cassava Starch Scaffold for Enhanced Neurovascular Bone Regeneration. ACS APPLIED MATERIALS & INTERFACES 2024; 16:35964-35984. [PMID: 38968558 DOI: 10.1021/acsami.4c03204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/07/2024]
Abstract
Developing a neurovascular bone repair scaffold with an appropriate mechanical strength remains a challenge. Calcium phosphate (CaP) is similar to human bone, but its scaffolds are inherently brittle and inactive, which require recombination with active ions and polymers for bioactivity and suitable strength. This work discussed the synthesis of amorphous magnesium-calcium pyrophosphate (AMCP) and the subsequent development of a humidity-responsive AMCP/cassava starch (CS) scaffold. The scaffold demonstrated enhanced mechanical properties by strengthening the intermolecular hydrogen bonds and ionic bonds between AMCP and CS during the gelatinization and freeze-thawing processes. The release of active ions was rapid initially and stabilized into a long-term stable release after 3 days, which is well-matched with new bone growth. The release of pyrophosphate ions endowed the scaffold with antibacterial properties. At the cellular level, the released active ions simultaneously promoted the proliferation and mineralization of osteoblasts, the proliferation and migration of endothelial cells, and the proliferation of Schwann cells. At the animal level, the scaffold was demonstrated to promote vascular growth and peripheral nerve regeneration in a rat skull defect experiment, ultimately resulting in the significant and rapid repair of bone defects. The construction of the AMCP/CS scaffold offers practical suggestions and references for neurovascular bone repair.
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Affiliation(s)
- Mengmeng Yang
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
- Jiangsu Key Laboratory for Advanced Metallic Materials, Nanjing 211189, Jiangsu, China
- Institute of Biomedical Devices (Suzhou), Southeast University, Suzhou 215163, China
| | - Xiang Cai
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
- Jiangsu Key Laboratory for Advanced Metallic Materials, Nanjing 211189, Jiangsu, China
| | - Cheng Wang
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
| | - Pengyin Li
- Center of Medical Physics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou 213003, Jiangsu, China
| | - Shaoqing Chen
- Center of Medical Physics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou 213003, Jiangsu, China
| | - Chun Liu
- Center of Medical Physics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou 213003, Jiangsu, China
| | - Yao Wang
- Department of Emergency, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Kun Qian
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
| | - Qiangsheng Dong
- School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Feng Xue
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
- Jiangsu Key Laboratory for Advanced Metallic Materials, Nanjing 211189, Jiangsu, China
- Institute of Biomedical Devices (Suzhou), Southeast University, Suzhou 215163, China
| | - Chenglin Chu
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
- Jiangsu Key Laboratory for Advanced Metallic Materials, Nanjing 211189, Jiangsu, China
| | - Jing Bai
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
- Jiangsu Key Laboratory for Advanced Metallic Materials, Nanjing 211189, Jiangsu, China
- Institute of Biomedical Devices (Suzhou), Southeast University, Suzhou 215163, China
- Jiangsu Key Laboratory for Light Metal Alloys, Nanjing 211212, China
| | - Qizhan Liu
- School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China
- Center for Global Health, The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Xinye Ni
- Center of Medical Physics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou 213003, Jiangsu, China
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Pardakhty A, Ranjbar M, Yahyapour M. Eco-friendly synthesis of the Li/Al in nonionic surfactant-based vesicles (niosomes) modified with graphene oxide quantum dot nanostructures for controlled released of chlorpheniramine maleate. LUMINESCENCE 2021; 36:1638-1647. [PMID: 34142436 DOI: 10.1002/bio.4105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/07/2021] [Accepted: 06/13/2021] [Indexed: 11/07/2022]
Abstract
The aim of the present work was the preparation of Li/Al nanoparticles (NPs) functionalized with graphene oxide quantum dots (GOQDs) for the controlled release of chlorpheniramine maleate (CPAM). The role of lemon and egg white extracts as oxidation agents were investigated for the morphology and particle size of the products. GOQDs were synthesized using green, environmentally friendly, and cost-effective precursors. This work demonstrates that Li/Al NPs functionalized with graphene oxide as a nanolayer structure can be used as efficient nanocarriers for loading and delivery of CPAM as water-insoluble aromatic drugs The final products were identified with X-ray diffraction, scanning electron microscopy, atomic force microscopy, ultraviolet-visible spectroscopy, dynamic light scattering, thermogravimetric analysis, and transmission electron microscopy nitrogen adsorption [i.e. Brunauer-Emmett-Teller (BET) surface area analysis] techniques. The calibration curve for Li/Al nanoparticles functionalized with GOQDs for controlled released of CPAM was calculated as y = 0.0137x + 0.0103 with R2 = 0.9995. The data found through BET and Barrett-Joyner-Halenda analysis using the adsorption/desorption isotherm method demonstrated by total pore volumes and dead volume were calculated respectively as 0.162 nm2 , 0.0439 cm3 g-1 . The mean pore diameter was calculated as 20.33 nm using BET isotherm data.
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Affiliation(s)
- Abbas Pardakhty
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mehdi Ranjbar
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.,Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Moghadeseh Yahyapour
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
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Unbehau R, Luthringer-Feyerabend BJC, Willumeit-Römer R. The impact of brain cell metabolism and extracellular matrix on magnesium degradation. Acta Biomater 2020; 116:426-437. [PMID: 32890748 DOI: 10.1016/j.actbio.2020.08.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/13/2020] [Accepted: 08/28/2020] [Indexed: 01/09/2023]
Abstract
Due to its degradability, magnesium holds potential for the application as a base material for local treatment systems. Particularly for the therapy of severe brain-related diseases, local approaches are advantageous. To confirm the suitability of magnesium as a material for neural implants, information on the interaction of brain cells with magnesium is essential. Initial steps of such an evaluation need to include not only cytocompatibility tests but also the analysis of the in vitro material degradation to predict in vivo material performance. Considering the sensitivity and functional importance of neural tissue, an in-depth understanding of the processes involved is of particular relevance. Here, we investigate the influence of four different brain cell types and fibroblasts on magnesium degradation in direct material contact. Our findings indicate cell type as well as cell density-dependent degradation behavior. Metabolic activity (lactate content) appears to be crucial for degradation promotion. Extracellular matrix composition, distribution, and matrix/cell ratios are analyzed to elucidate the cell-material interactions further. Statement of Significance Thanks to their degradability, magnesium (Mg)-based materials could be promising biomaterials for local ion or even drug delivery strategies for the treatment of severe brain-related diseases. To confirm the suitability of Mg as a neural implant material, information on the interaction of brain cells with Mg is essential. Initial steps of such an evaluation need to include cytocompatibility tests and the analysis of the in vitro material degradation to predict in vivo material performance. The present study provides data on the influence of different brain cell types on Mg degradation in direct material contact. Our findings indicate cell type and cell density-dependent degradation behavior, and elucidate the role of cell metabolites and extracellular matrix molecules in the underlying degradation mechanisms.
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Affiliation(s)
- Reneé Unbehau
- Institute of Materials Research, Division for Metallic Biomaterials, Helmholtz-Zentrum Geesthacht (HZG), Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Bérengère J C Luthringer-Feyerabend
- Institute of Materials Research, Division for Metallic Biomaterials, Helmholtz-Zentrum Geesthacht (HZG), Max-Planck-Str. 1, 21502 Geesthacht, Germany.
| | - Regine Willumeit-Römer
- Institute of Materials Research, Division for Metallic Biomaterials, Helmholtz-Zentrum Geesthacht (HZG), Max-Planck-Str. 1, 21502 Geesthacht, Germany
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Badman RP, Moore SL, Killian JL, Feng T, Cleland TA, Hu F, Wang MD. Dextran-coated iron oxide nanoparticle-induced nanotoxicity in neuron cultures. Sci Rep 2020; 10:11239. [PMID: 32641693 PMCID: PMC7343881 DOI: 10.1038/s41598-020-67724-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 02/27/2020] [Indexed: 11/09/2022] Open
Abstract
Recent technological advances have introduced diverse engineered nanoparticles (ENPs) into our air, water, medicine, cosmetics, clothing, and food. However, the health and environmental effects of these increasingly common ENPs are still not well understood. In particular, potential neurological effects are one of the most poorly understood areas of nanoparticle toxicology (nanotoxicology), in that low-to-moderate neurotoxicity can be subtle and difficult to measure. Culturing primary neuron explants on planar microelectrode arrays (MEAs) has emerged as one of the most promising in vitro techniques with which to study neuro-nanotoxicology, as MEAs enable the fluorescent tracking of nanoparticles together with neuronal electrical activity recording at the submillisecond time scale, enabling the resolution of individual action potentials. Here we examine the dose-dependent neurotoxicity of dextran-coated iron oxide nanoparticles (dIONPs), a common type of functionalized ENP used in biomedical applications, on cultured primary neurons harvested from postnatal day 0-1 mouse brains. A range of dIONP concentrations (5-40 µg/ml) were added to neuron cultures, and cells were plated either onto well plates for live cell, fluorescent reactive oxidative species (ROS) and viability observations, or onto planar microelectrode arrays (MEAs) for electrophysiological measurements. Below 10 µg/ml, there were no dose-dependent cellular ROS increases or effects in MEA bursting behavior at sub-lethal dosages. However, above 20 µg/ml, cell death was obvious and widespread. Our findings demonstrate a significant dIONP toxicity in cultured neurons at concentrations previously reported to be safe for stem cells and other non-neuronal cell types.
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Affiliation(s)
- Ryan P Badman
- Department of Physics and LASSP, Cornell University, Ithaca, NY, 14853, USA.,Center for Brain Science, RIKEN, Saitama, 351-0198, Japan
| | - Shanna L Moore
- Department of Physics and LASSP, Cornell University, Ithaca, NY, 14853, USA.,Howard Hughes Medical Institute, Cornell University, Ithaca, NY, 14853, USA
| | - Jessica L Killian
- Department of Physics and LASSP, Cornell University, Ithaca, NY, 14853, USA.,Howard Hughes Medical Institute, Cornell University, Ithaca, NY, 14853, USA.,Quantum Biosystems, Menlo Park, CA, 94025, USA
| | - Tuancheng Feng
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Thomas A Cleland
- Department of Psychology, Cornell University, Ithaca, NY, 14853, USA
| | - Fenghua Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Michelle D Wang
- Department of Physics and LASSP, Cornell University, Ithaca, NY, 14853, USA. .,Howard Hughes Medical Institute, Cornell University, Ithaca, NY, 14853, USA.
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Kosnik MB, Strickland JD, Marvel SW, Wallis DJ, Wallace K, Richard AM, Reif DM, Shafer TJ. Concentration-response evaluation of ToxCast compounds for multivariate activity patterns of neural network function. Arch Toxicol 2020; 94:469-484. [PMID: 31822930 PMCID: PMC7371233 DOI: 10.1007/s00204-019-02636-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/26/2019] [Indexed: 01/01/2023]
Abstract
The US Environmental Protection Agency's ToxCast program has generated toxicity data for thousands of chemicals but does not adequately assess potential neurotoxicity. Networks of neurons grown on microelectrode arrays (MEAs) offer an efficient approach to screen compounds for neuroactivity and distinguish between compound effects on firing, bursting, and connectivity patterns. Previously, single concentrations of the ToxCast Phase II library were screened for effects on mean firing rate (MFR) in rat primary cortical networks. Here, we expand this approach by retesting 384 of those compounds (including 222 active in the previous screen) in concentration-response across 43 network activity parameters to evaluate neural network function. Using hierarchical clustering and machine learning methods on the full suite of chemical-parameter response data, we identified 15 network activity parameters crucial in characterizing activity of 237 compounds that were response actives ("hits"). Recognized neurotoxic compounds in this network function assay were often more potent compared to other ToxCast assays. Of these chemical-parameter responses, we identified three k-means clusters of chemical-parameter activity (i.e., multivariate MEA response patterns). Next, we evaluated the MEA clusters for enrichment of chemical features using a subset of ToxPrint chemotypes, revealing chemical structural features that distinguished the MEA clusters. Finally, we assessed distribution of neurotoxicants with known pharmacology within the clusters and found that compounds segregated differentially. Collectively, these results demonstrate that multivariate MEA activity patterns can efficiently screen for diverse chemical activities relevant to neurotoxicity, and that response patterns may have predictive value related to chemical structural features.
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Affiliation(s)
- Marissa B Kosnik
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
- Science for Life Laboratory, Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Jenna D Strickland
- Axion Biosystems, Atlanta, GA, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| | - Skylar W Marvel
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Dylan J Wallis
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Kathleen Wallace
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, MD B105-05, Research Triangle Park, NC, 27711, USA
| | - Ann M Richard
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, MD B105-05, Research Triangle Park, NC, 27711, USA
| | - David M Reif
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Timothy J Shafer
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, MD B105-05, Research Triangle Park, NC, 27711, USA.
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Shafer TJ. Application of Microelectrode Array Approaches to Neurotoxicity Testing and Screening. ADVANCES IN NEUROBIOLOGY 2019; 22:275-297. [PMID: 31073941 DOI: 10.1007/978-3-030-11135-9_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neurotoxicity can be defined by the ability of a drug or chemical to alter the physiology, biochemistry, or structure of the nervous system in a manner that may negatively impact the health or function of the individual. Electrophysiological approaches have been utilized to study the mechanisms underlying neurotoxic actions of drugs and chemicals for over 50 years, and in more recent decades, high-throughput patch-clamp approaches have been utilized by the pharmaceutical industry for drug development. The use of microelectrode array recordings to study neural network electrophysiology is a relatively newer approach, with commercially available systems becoming available only in the early 2000s. However, MEAs have been rapidly adopted as a useful approach for neurotoxicity testing. In this chapter, I will review the use of MEA approaches as they have been applied to the field of neurotoxicity testing, especially as they have been applied to the need to screen large numbers of chemicals for neurotoxicity and developmental neurotoxicity. In addition, I will also identify challenges for the field that when addressed will improve the utility of MEA approaches for toxicity testing.
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Affiliation(s)
- Timothy J Shafer
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory (NHEERL), US EPA, Research Triangle Park, NC, USA.
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Monfared A, Ghaee A, Ebrahimi-Barough S. Fabrication of tannic acid/poly(N-vinylpyrrolidone) layer-by-layer coating on Mg-based metallic glass for nerve tissue regeneration application. Colloids Surf B Biointerfaces 2018; 170:617-626. [DOI: 10.1016/j.colsurfb.2018.06.060] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 05/16/2018] [Accepted: 06/27/2018] [Indexed: 12/25/2022]
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8
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Joo S, Nam Y. Slow-Wave Recordings From Micro-Sized Neural Clusters Using Multiwell Type Microelectrode Arrays. IEEE Trans Biomed Eng 2018; 66:403-410. [PMID: 29993399 DOI: 10.1109/tbme.2018.2843793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The use of microelectrode array (MEA) recordings is a very effective neurophysiological method because it is able to continuously and noninvasively obtain the spatiotemporal information of electrical activity from many neurons constituting a neural network. Very recently, studies have been published that used MEAs for the measurement of a low-frequency component of electrical activity as an indicator of diverse activity of cultured neurons. The occurrence of low-frequency activities has electrophysiological information that does not include the information from fast spikes. However, there is no in vitro experimental model suitable for measuring the low-frequency activities (slow-waves) for further study. METHODS Neural clusters consisting of dozens of neurons were placed directly onto each electrode of an MEA from which fast spikes and slow-waves were measured. RESULTS We obtained sufficient data on the early development patterns of the slow-waves and the spikes measured from many independent neural clusters confirming that the slow-waves occurred first before the emergence of the spikes in the neural clusters. We also showed that changes in the occurrence frequency of the slow-waves for synaptic blockers were measured from a large number of independent cultures. CONCLUSION Microsized neural cluster arrays, which can be combined with conventional MEAs, are suitable for multiple simultaneous recordings of slow-waves. SIGNIFICANCE Our technology provides a simple but useful method to study the generation of a low-frequency component of the electrical activity in cultured neural networks that are not yet well known as well as to expand the use of conventional MEAs.
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Electrophysiological evidence of RML12 mosquito cell line towards neuronal differentiation by 20-hydroxyecdysdone. Sci Rep 2018; 8:10109. [PMID: 29973702 PMCID: PMC6031678 DOI: 10.1038/s41598-018-28357-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 06/07/2018] [Indexed: 01/06/2023] Open
Abstract
Continuous cell lines from insect larval tissues are widely used in different research domains, such as virology, insect immunity, gene expression, and bio pharmacology. Previous study showed that introduction of 20-hydroxyecdysone to Spodoptera cell line induced a neuron-like morphology with neurite extensions. Despite some results suggesting potential presence of neuro-receptors, no study so far has shown that these neuron-induced cells were functional. Here, using microelectrode arrays, we showed that the mosquito cell line, RML12, differentiated with 20-hydroxyecdysone, displays spontaneous electrophysiological activity. Results showed that these cells can be stimulated by GABAergic antagonist as well as nicotinic agonist. These results provide new evidence of neuron-like functionality of 20-hydroxyecdysone induced differentiated mosquito cell line. Finally, we used this new model to test the effects of two insecticides, temephos and permethrin. Our analysis revealed significant changes in the spiking activity after the introduction of these insecticides with prolonged effect on the neuronal activity. We believe that this differentiated mosquito neuronal cell model can be used for high-throughput screening of new pesticides on insect nervous system instead of primary neurons or in vivo studies.
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Quantitative analysis of near-implant magnesium accumulation for a Si-containing coated AZ31 cage from a goat cervical spine fusion model. BMC Musculoskelet Disord 2018; 19:105. [PMID: 29618341 PMCID: PMC5885299 DOI: 10.1186/s12891-018-2027-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 03/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Magnesium (Mg) released from Mg-based implants degradation is believed to be effective in improving osteogenesis, however, studies focusing on Mg-based interbody cages are limited and fusion success was never reported. As excessive Mg accumulation can inhibit new bone formation, this study is designed to explain the possible reasons for the fusion failure of Mg-based cages by analyzing the relationships between the intervertebral Mg accumulation and the resulting interbody fusion. METHODS The experimental cage was consisted of magnesium alloy (AZ31) substrate and Silicon (Si) -containing coating. C3/C4 and C5/C6 of 24 goats were implanted with cage or autologous iliac crest bone graft (Control group), which were analyzed at 3, 6, 12, and 24 weeks post-operatively. Intervertebral Mg concentrations, Mg-related Calcium (Ca)/ Phosphorus (P) ratios, radiological evaluations and histological findings were recorded for analyzing the relationships between the three of cage corrosion, Mg accumulation, and interbody fusion. RESULTS Intervertebral Mg levels were significantly increased after cage implantation, especially in the areas that were closer to the cages at 3 weeks post-operatively, and these increased concentrations could persist up to 12 weeks post-operatively, indicating a relatively rapid corrosion process. Significantly lower Mg levels were only found at 24 weeks post-operatively, but these levels were still higher than those of the control group. In addition, Mg was found to be widely distributed at the intervertebral space since high Mg concentrations could even be detected at the posterior boundary of the vertebral body. Under this Mg accumulation profile, interbody fusion was not achieved, as indicated by the decreased Ca/P ratios, low CT fusion scores and negative histological results. CONCLUSIONS Intervertebral excessive Mg accumulation might be the primary reason for interbody fusion failure. Quantitative Mg analysis can offer insight into the association between cage degeneration and biological response.
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Poly (3,4-ethylenedioxythiophene) graphene oxide composite coatings for controlling magnesium implant corrosion. Acta Biomater 2017. [PMID: 27867108 DOI: 10.1016/j.actbio.2016.11.039.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Magnesium (Mg) is a promising biodegradable implant material because of its appropriate mechanical properties and safe degradation products. However, in vivo corrosion speed and hydrogen gas production need to be controlled for uses in biomedical applications. Here we report the development of a conducting polymer 3,4-ethylenedioxythiphene (PEDOT) and graphene oxide (GO) composite coating as a corrosion control layer. PEDOT/GO was electropolymerized on Mg samples in ethanol media. The coated Mg samples were subjected to various corrosion tests. The PEDOT/GO coating significantly reduced the rate of corrosion as evidenced by lower Mg ion concentration and pH of the corrosion media. In addition, the coating decreased the evolved hydrogen. Electrochemical analysis of the corroding samples showed more positive corrosion potential, a decreased corrosion current, and an increase in the polarization resistance. PEDOT/GO corrosion protection is attributed to three factors; an initial passive layer preventing solution ingress, buildup of negative charges in the film, and formation of corrosion protective Mg phosphate layer through redox coupling with Mg corrosion. To explore the biocompatibility of the coated implants in vitro, corrosion media from PEDOT/GO coated or uncoated Mg samples were exposed to cultured neurons where PEDOT/GO coated samples showed decreased toxicity. These results suggest that PEDOT/GO coating will be an effective treatment for controlling corrosion of Mg based medical implants. STATEMENT OF SIGNIFICANCE Coating Mg substrates with a PEDOT/GO composite coating showed a significant decrease in corrosion rate. While conducting polymer coatings have been used to prevent corrosion on various metals, there has been little work on the use of these coatings for Mg. Additionally, to our knowledge, there has not been a report of the combined used of conducting polymer and GO as a corrosion control layer. Corrosion control is attributed to an initial barrier layer followed by electrochemical coupling of the PEDOT/GO coating with the substrate to facilitate the formation of a protective phosphate layer. This coupling also resulted in a decrease in hydrogen produced during corrosion, which could further improve the host tissue integration of Mg implants. This work elaborates on the potential for electroactive polymers to serve as corrosion control methods.
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12
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Catt K, Li H, Cui XT. Poly (3,4-ethylenedioxythiophene) graphene oxide composite coatings for controlling magnesium implant corrosion. Acta Biomater 2017; 48:530-540. [PMID: 27867108 PMCID: PMC6003706 DOI: 10.1016/j.actbio.2016.11.039] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 11/12/2016] [Accepted: 11/17/2016] [Indexed: 02/02/2023]
Abstract
Magnesium (Mg) is a promising biodegradable implant material because of its appropriate mechanical properties and safe degradation products. However, in vivo corrosion speed and hydrogen gas production need to be controlled for uses in biomedical applications. Here we report the development of a conducting polymer 3,4-ethylenedioxythiphene (PEDOT) and graphene oxide (GO) composite coating as a corrosion control layer. PEDOT/GO was electropolymerized on Mg samples in ethanol media. The coated Mg samples were subjected to various corrosion tests. The PEDOT/GO coating significantly reduced the rate of corrosion as evidenced by lower Mg ion concentration and pH of the corrosion media. In addition, the coating decreased the evolved hydrogen. Electrochemical analysis of the corroding samples showed more positive corrosion potential, a decreased corrosion current, and an increase in the polarization resistance. PEDOT/GO corrosion protection is attributed to three factors; an initial passive layer preventing solution ingress, buildup of negative charges in the film, and formation of corrosion protective Mg phosphate layer through redox coupling with Mg corrosion. To explore the biocompatibility of the coated implants in vitro, corrosion media from PEDOT/GO coated or uncoated Mg samples were exposed to cultured neurons where PEDOT/GO coated samples showed decreased toxicity. These results suggest that PEDOT/GO coating will be an effective treatment for controlling corrosion of Mg based medical implants. STATEMENT OF SIGNIFICANCE Coating Mg substrates with a PEDOT/GO composite coating showed a significant decrease in corrosion rate. While conducting polymer coatings have been used to prevent corrosion on various metals, there has been little work on the use of these coatings for Mg. Additionally, to our knowledge, there has not been a report of the combined used of conducting polymer and GO as a corrosion control layer. Corrosion control is attributed to an initial barrier layer followed by electrochemical coupling of the PEDOT/GO coating with the substrate to facilitate the formation of a protective phosphate layer. This coupling also resulted in a decrease in hydrogen produced during corrosion, which could further improve the host tissue integration of Mg implants. This work elaborates on the potential for electroactive polymers to serve as corrosion control methods.
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Affiliation(s)
- Kasey Catt
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Huaxiu Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - X Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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