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Sabetkish S, Currie P, Meagher L. Recent trends in 3D bioprinting technology for skeletal muscle regeneration. Acta Biomater 2024:S1742-7061(24)00221-6. [PMID: 38697381 DOI: 10.1016/j.actbio.2024.04.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/05/2024]
Abstract
Skeletal muscle is a pro-regenerative tissue, that utilizes a tissue-resident stem cell system to effect repair upon injury. Despite the demonstrated efficiency of this system in restoring muscle mass after many acute injuries, in conditions of severe trauma such as those evident in volumetric muscle loss (VML) (>20 % by mass), this self-repair capability is unable to restore tissue architecture, requiring interventions which currently are largely surgical. As a possible alternative, the generation of artificial muscle using tissue engineering approaches may also be of importance in the treatment of VML and muscle diseases such as dystrophies. Three-dimensional (3D) bioprinting has been identified as a promising technique for regeneration of the complex architecture of skeletal muscle. This review discusses existing treatment strategies following muscle damage, recent progress in bioprinting techniques, the bioinks used for muscle regeneration, the immunogenicity of scaffold materials, and in vitro and in vivo maturation techniques for 3D bio-printed muscle constructs. The pros and cons of these bioink formulations are also highlighted. Finally, we present the current limitations and challenges in the field and critical factors to consider for bioprinting approaches to become more translationa and to produce clinically relevant engineered muscle. STATEMENT OF SIGNIFICANCE: This review discusses the physiopathology of muscle injuries and existing clinical treatment strategies for muscle damage, the types of bioprinting techniques that have been applied to bioprinting of muscle, and the bioinks commonly used for muscle regeneration. The pros and cons of these bioinks are highlighted. We present a discussion of existing gaps in the literature and critical factors to consider for the translation of bioprinting approaches and to produce clinically relevant engineered muscle. Finally, we provide insights into what we believe will be the next steps required before the realization of the application of tissue-engineered muscle in humans. We believe this manuscript is an insightful, timely, and instructive review that will guide future muscle bioprinting research from a fundamental construct creation approach, down a translational pathway to achieve the desired impact in the clinic.
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Affiliation(s)
- Shabnam Sabetkish
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia; ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Peter Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia; ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, Australia; ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia.
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2
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Huynh GT, Tunny SS, Frith JE, Meagher L, Corrie SR. Organosilica Nanosensors for Monitoring Spatiotemporal Changes in Oxygen Levels in Bacterial Cultures. ACS Sens 2024. [PMID: 38687178 DOI: 10.1021/acssensors.3c02747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Oxygen plays a central role in aerobic metabolism, and while many approaches have been developed to measure oxygen concentration in biological environments over time, monitoring spatiotemporal changes in dissolved oxygen levels remains challenging. To address this, we developed a ratiometric core-shell organosilica nanosensor for continuous, real-time optical monitoring of oxygen levels in biological environments. The nanosensors demonstrate good steady state characteristics (KpSV = 0.40 L/mg, R2 = 0.95) and respond reversibly to changes in oxygen concentration in buffered solutions and report similar oxygen level changes in response to bacterial cell growth (Escherichia coli) in comparison to a commercial bulk optode-based sensing film. We further demonstrated that the oxygen nanosensors could be distributed within a growing culture of E. coli and used to record oxygen levels over time and in different locations within a static culture, opening the possibility of spatiotemporal monitoring in complex biological systems.
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Affiliation(s)
- Gabriel T Huynh
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
- Commonwealth Scientific and Industrial Research Organization (CSIRO) Manufacturing, Clayton, VIC 3168, Australia
| | - Salma S Tunny
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Jessica E Frith
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Simon R Corrie
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
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Lai G, Meagher L. Versatile xanthan gum-based support bath material compatible with multiple crosslinking mechanisms: rheological properties, printability, and cytocompatibility study. Biofabrication 2024; 16:035005. [PMID: 38565131 DOI: 10.1088/1758-5090/ad39a8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 04/02/2024] [Indexed: 04/04/2024]
Abstract
Extrusion-based bioprinting is a promising technology for the fabrication of complex three-dimensional (3D) tissue-engineered constructs. To further improve the printing accuracy and provide mechanical support during the printing process, hydrogel-based support bath materials have been developed. However, the gel structure of some support bath materials can be compromised when exposed to certain bioink crosslinking cues, hence their compatibility with bioinks can be limited. In this study, a xanthan gum-based composite support material compatible with multiple crosslinking mechanisms is developed. Different support bath materials can have different underlying polymeric structures, for example, particulate suspensions and polymer solution with varying supramolecular structure) and these properties are governed by a variety of different intermolecular interactions. However, common rheological behavior can be expected because they have similar demonstrated performance and functionality. To provide a detailed exploration/identification of the common rheological properties expressed by different support bath materials from a unified perspective, benchmark support bath materials from previous studies were prepared. A comparative rheological study revealed both the structural and shear behavior characteristics shared by support bath materials, including yield stress, gel complex moduli, shear-thinning behavior, and self-healing properties. Gel structural stability and functionality of support materials were tested in the presence of various crosslinking stimuli, confirming the versatility of the xanthan-based support material. We further investigated the effect of support materials and the diameter of extrusion needles on the printability of bioinks to demonstrate the improvement in bioink printability and structural integrity. Cytotoxicity and cell encapsulation viability tests were carried out to confirm the cell compatibility of the xanthan gum-based support bath material. We propose and demonstrate the versatility and compatibility of the novel support bath material and provide detailed new insight into the essential properties and behavior of these materials that serve as a guide for further development of support bath-based 3D bioprinting.
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Affiliation(s)
- Guanyu Lai
- Department of Materials Science and Engineering, Monash University, Clayton, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, Australia
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Yao Y, Coleman HA, Meagher L, Forsythe JS, Parkington HC. 3D Functional Neuronal Networks in Free-Standing Bioprinted Hydrogel Constructs. Adv Healthc Mater 2023; 12:e2300801. [PMID: 37369123 DOI: 10.1002/adhm.202300801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 06/29/2023]
Abstract
The composition, elasticity, and organization of the extracellular matrix within the central nervous system contribute to the architecture and function of the brain. From an in vitro modeling perspective, soft biomaterials are needed to mimic the 3D neural microenvironments. While many studies have investigated 3D culture and neural network formation in bulk hydrogel systems, these approaches have limited ability to position cells to mimic sophisticated brain architectures. In this study, cortical neurons and astrocytes acutely isolated from the brains of rats are bioprinted in a hydrogel to form 3D neuronal constructs. Successful bioprinting of cellular and acellular strands in a multi-bioink approach allows the subsequent formation of gray- and white-matter tracts reminiscent of cortical structures. Immunohistochemistry shows the formation of dense, 3D axon networks. Calcium signaling and extracellular electrophysiology in these 3D neuronal networks confirm spontaneous activity in addition to evoked activities under pharmacological and electrical stimulation. The system and bioprinting approaches are capable of fabricating soft, free-standing neuronal structures of different bioink and cell types with high resolution and throughput, which provide a promising platform for understanding fundamental questions of neural networks, engineering neuromorphic circuits, and for in vitro drug screening.
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Affiliation(s)
- Yue Yao
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia
- School of Physics, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Harold A Coleman
- Department of Physiology, Monash University, Clayton, VIC, 3800, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, 3800, Australia
| | - John S Forsythe
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, 3800, Australia
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Yao Y, Molotnikov A, Parkington H, Meagher L, Forsythe JS. Extrusion 3D bioprinting of functional self-supporting neural constructs using a photoclickable gelatin bioink. Biofabrication 2022; 14. [PMID: 35545019 DOI: 10.1088/1758-5090/ac6e87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 05/11/2022] [Indexed: 11/12/2022]
Abstract
Many in vitro models of neural physiology utilize neuronal networks established on two-dimensional substrates. Despite the simplicity of these 2D neuronal networks, substrate stiffness may influence cell morphology, network interactions and how neurons communicate and function. With this perspective, 3D gel encapsulation is a powerful to recapitulating aspects of in vivo features, yet such an approach is often limited in terms of the level of resolution and feature size relevant for modelling aspects of brain architecture. Here, we report 3D bioplotting of rat primary cortical neural cells using a hydrogel system comprising gelatin norbornene (GelNB) and poly (ethylene glycol) dithiol (PEGdiSH). This bioink benefits from a rapid photo-click chemistry, yielding 8-layer crosshatch neural scaffolds and a filament width of 350 µm. The printability of this system depends on hydrogel concentration, printing temperature, extrusion pressure and speed. These parameters were studied via quantitative comparison between rheology and filament dimensions to determine the optimal printing conditions. Under optimal conditions, cell viability of bioprinted primary cortical neurons at day 1 (68 ± 2%) and at day 7 (68 ± 1%) were comparable to the 2D control group (72 ± 7%). The present study relates material rheology and filament dimensions to generate compliant free-standing neural constructs through bioplotting of low-concentration GelNB-PEGdiSH, which may provide a step forward to study 3D neuronal function and network formation.
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Affiliation(s)
- Yue Yao
- Materials Science and Engineering, Monash University, 20 Research Way, Monash University, Clayton, Victoria, 3800, AUSTRALIA
| | - Andrey Molotnikov
- School of Engineering, RMIT University, City Campus, Melbourne, Victoria, 3001, AUSTRALIA
| | - Helena Parkington
- Department of Physiology, Monash University, Clayton Campus, Clayton, Victoria, 3800, AUSTRALIA
| | - Laurence Meagher
- Materials Science and Engineering, Monash University, 22/109 Alliance Lane, Clayton, Clayton, Victoria, 3800, AUSTRALIA
| | - John S Forsythe
- Materials Science Engineering, Monash University, 20 Research Way, Monash University, Clayton, Victoria, 3800, AUSTRALIA
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Subasic CN, Ardana A, Chan LJ, Huang F, Scoble JA, Butcher NJ, Meagher L, Chiefari J, Kaminskas LM, Williams CC. Poly(HPMA-co-NIPAM) copolymer as an alternative to polyethylene glycol-based pharmacokinetic modulation of therapeutic proteins. Int J Pharm 2021; 608:121075. [PMID: 34481889 DOI: 10.1016/j.ijpharm.2021.121075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 12/21/2022]
Abstract
PEGylation is the standard approach for prolonging the plasma exposure of protein therapeutics but has limitations. We explored whether polymers prepared by Reversible Addition-Fragmentation chain-Transfer (RAFT) may provide better alternatives to polyethylene glycol (PEG). Four RAFT polymers were synthesised with varying compositions, molar mass (Mn), and structures, including a homopolymer of N-(2-hydroxypropyl)methacrylamide, (pHPMA) and statistical copolymers of HPMA with poly(ethylene glycol methyl ether acrylate) p(HPMA-co-PEGA); HPMA and N-acryloylmorpholine, p(HPMA-co-NAM); and HPMA and N-isopropylacrylamide, p(HPMA-co-NIPAM). The intravenous pharmacokinetics of the polymers were then evaluated in rats. The in vitro activity and in vivo pharmacokinetics of p(HPMA-co-NIPAM)-conjugated trastuzumab Fab' and full length mAb were then evaluated. p(HPMA-co-NIPAM) prolonged plasma exposure more avidly compared to the other p(HPMA) polymers or PEG, irrespective of molecular weight. When conjugated to trastuzumab-Fab', p(HPMA-co-NIPAM) prolonged plasma exposure of the Fab' similar to PEG-Fab'. The generation of anti-PEG IgM in rats 7 days after intravenous and subcutaneous dosing of p(HPMA-co-NIPAM) conjugated trastuzumab mAb was also examined and was shown to exhibit lower immunogenicity than the PEGylated construct. These data suggest that p(HPMA-co-NIPAM) has potential as a promising copolymer for use as an alternative conjugation strategy to PEG, to prolong the plasma exposure of therapeutic proteins.
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Affiliation(s)
- Christopher N Subasic
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Aditya Ardana
- CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Linda J Chan
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Fei Huang
- CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Judith A Scoble
- CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Neville J Butcher
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Laurence Meagher
- CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052, Australia; Department of Materials Science and Engineering, Monash University, 20 Research Way, Clayton, Victoria 3168, Australia
| | - John Chiefari
- CSIRO Manufacturing, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Lisa M Kaminskas
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD 4072, Australia; Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
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7
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Huynh GT, Kesarwani V, Walker JA, Frith JE, Meagher L, Corrie SR. Review: Nanomaterials for Reactive Oxygen Species Detection and Monitoring in Biological Environments. Front Chem 2021; 9:728717. [PMID: 34568279 PMCID: PMC8461210 DOI: 10.3389/fchem.2021.728717] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/25/2021] [Indexed: 12/19/2022] Open
Abstract
Reactive oxygen species (ROS) and dissolved oxygen play key roles across many biological processes, and fluorescent stains and dyes are the primary tools used to quantify these species in vitro. However, spatio-temporal monitoring of ROS and dissolved oxygen in biological systems are challenging due to issues including poor photostability, lack of reversibility, and rapid off-site diffusion. In particular, ROS monitoring is hindered by the short lifetime of ROS molecules and their low abundance. The combination of nanomaterials and fluorescent detection has led to new opportunities for development of imaging probes, sensors, and theranostic products, because the scaffolds lead to improved optical properties, tuneable interactions with cells and media, and ratiometric sensing robust to environmental drift. In this review, we aim to critically assess and highlight recent development in nanosensors and nanomaterials used for the detection of oxygen and ROS in biological systems, and their future potential use as diagnosis tools.
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Affiliation(s)
- Gabriel T. Huynh
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
| | - Vidhishri Kesarwani
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
| | - Julia A. Walker
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
| | - Jessica E. Frith
- Monash Institute of Medical Engineering, Monash University, Clayton, VIC, Australia
- Department of Material Science and Engineering, Monash University, Clayton, VIC, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, Australia
| | - Laurence Meagher
- Department of Material Science and Engineering, Monash University, Clayton, VIC, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, Australia
| | - Simon R. Corrie
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, Australia
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8
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Huynh GT, Henderson EC, Frith JE, Meagher L, Corrie SR. Stability and Performance Study of Fluorescent Organosilica pH Nanosensors. Langmuir 2021; 37:6578-6587. [PMID: 34009994 DOI: 10.1021/acs.langmuir.1c00936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Long-term stability and function are key challenges for optical nanosensors operating in complex biological environments. While much focus is rightly placed on issues related to specificity, sensitivity, reversibility, and response time, many nanosensors are not capable of transducing accurate results over prolonged time periods. Sensors could fail over time due to the degradation of scaffold material, degradation of signaling dyes and components, or a combination of both. It is critical to investigate how such degradative processes affect sensor output, as the consequences could be severe. Herein, we used fluorescent core-shell organosilica pH nanosensors as a model system, incubating them in a range of common aqueous solutions over time at different temperatures, and then searched for changes in fluorescence signal, particle size, and evidence of silica degradation. We found that these ratiometric nanosensors produced stable optical signals after aging for 30 days at 37 °C in standard saline buffers with and without 10% fetal bovine serum, and without any evidence of material degradation. Next, we evaluated their performance as real-time pH nanosensors in bacterial suspension cultures, observing a close agreement with a pH electrode for control nanosensors, yet observing obvious deviations in signal based on the aging conditions. The results show that while the organosilica scaffold does not degrade appreciably over time, careful selection of dyes and further systematic investigations into the effects of salt and protein levels are required to realize long-term stable nanosensors.
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Affiliation(s)
- Gabriel T Huynh
- Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC 3800, Australia
| | - Edward C Henderson
- Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC 3800, Australia
| | - Jessica E Frith
- Monash Institute of Medical Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Material Science and Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Laurence Meagher
- Department of Material Science and Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Simon R Corrie
- Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC 3800, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC 3800, Australia
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Garcia Cruz MDR, Postma A, Frith JE, Meagher L. Printability and bio-functionality of a shear thinning methacrylated xanthan - gelatin composite bioink. Biofabrication 2021; 13. [PMID: 33662950 DOI: 10.1088/1758-5090/abec2d] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 03/04/2021] [Indexed: 11/12/2022]
Abstract
3D bioprinting is a recent technique that can create complex cell seeded scaffolds and therefore holds great promise to revolutionize the biomedical sector by combining materials and structures that more closely mimic the 3D cell environment in tissues. The most commonly used biomaterials for printing are hydrogels, however, many of the hydrogels used still present issues of printability, stability, or poor cell-material interactions. We propose that bio-inks with intrinsic self-assembling and shear thinning properties, such as xanthan gum, can be methacrylated (XGMA) and combined with a bio-functional material such as gelatin methacryloyl (GelMa) to create a stable, cell-interactive bio-ink with improved properties for 3D bioprinting. These biomaterials have reduced viscosity under high shear and recover their viscosity rapidly after the shear is removed, retaining their shape, which translates to easier extrusion whilst maintaining good fidelity after printing. This was confirmed in printing studies, with measured normalized strand widths of 1.2 obtained for high gel concentrations (5+5 % XGMA-GelMA). Furthermore, the introduction of a secondary photo-cross-linking method allowed tuning of the mechanical properties of the hydrogel with stiffness between 15 and 30 kPa, as well as improving the stability of the hydrogel with retention of 75 % of its mass after 90 days. The hydrogel was shown to be biocompatible and bio-active with 97 % cell viability, and cell spreading after 7 days of culture for low gel concentrations (3+3 % XGMA-GelMA). Shear stresses were relatively low while printing (1 kPa) as a result of the shear thinning property of the material, which supported cell viability during extrusion. Finally, printed hydrogels retained high cell viability for lower gel concentrations, and showed improved cell viability for more concentrated hydrogels when compared to cells cultured in bulk hydrogels, presumably due to improved nutrient/oxygen diffusion and cell migration. In conclusion, stability and formulation of a XGMA-GelMA shear thinning composite hydrogel has been optimized to create a bio-functional bio-ink, with improved printability, and in vitro culture stability via secondary photo-induced cross-linking, making this composite a promising bio-ink for 3D bioprinting.
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Affiliation(s)
- Maria Del Rocio Garcia Cruz
- Material Science and Engineering, Monash University Faculty of Engineering, Wellington Rd, 3800, Clayton, Victoria, 3800, AUSTRALIA
| | - Almar Postma
- Manufacturing, CSIRO Manufacturing and Materials Technology, Research Way, Clayton, Victoria, 3168, AUSTRALIA
| | - Jessica Ellen Frith
- Material Science and Engineering, Monash University Faculty of Engineering, Wellington Rd, Clayton, Victoria, 3800, AUSTRALIA
| | - Laurence Meagher
- Materials Science and Engineering, Monash University, 22/109 Alliance Lane, Clayton, Clayton, Victoria, 3800, AUSTRALIA
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10
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Wang H, Evans D, Voelcker NH, Griesser HJ, Meagher L. Modulation of substrate van der Waals forces using varying thicknesses of polymer overlayers. J Colloid Interface Sci 2020; 580:690-699. [PMID: 32712475 DOI: 10.1016/j.jcis.2020.07.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/02/2020] [Accepted: 07/07/2020] [Indexed: 11/18/2022]
Abstract
Thin polymeric coatings are commonly used for altering surface properties and modulating the interfacial performance of materials. Possible contributions from the substrate to the interfacial forces and effects are, however, usually ignored and are not well understood, nor is it established how the coating thickness modulates and eventually eliminates contributions from substrates to the van der Waals (vdW) interfacial force. In this study we quantified, by colloid-probe atomic force microscope (AFM) and by theoretical calculations, the interfacial vdW contributions from substrates acting through ethanol plasma polymer (EtOHpp) coatings of a range of thicknesses on Au and Si bulk materials. In approach force curves against EtOHpp-coated Au substrates the magnitude of the vdW force decreased as the EtOHpp coating thickness increased to 18 nm and then plateaued with further increases in coating thickness, providing direct evidence for a contribution to the total interfacial vdW force from the Au substrate acting through thin coatings. The experimental observations accord with theoretical calculations of the thickness dependence of Hamaker coefficients derived from rigorous simulation using the Lifshitz theory. In addition, the measured forces agree well with theoretical predictions including correction for finite roughness. Thus, our experimental and theoretical results establish how the thickness of polymer thin film coatings modulates the total interfacial vdW force and how this can be used to tune the net vdW force so as to either contain a large substrate contribution or arise predominantly from the polymeric overlayer. Our findings enable rational design of coating thickness to tailor interfacial interactions and material performance.
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Affiliation(s)
- Hongfang Wang
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia.
| | - Drew Evans
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Nicolas H Voelcker
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia; Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia; Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Hans J Griesser
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia.
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
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11
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Cherian DS, Bhuvan T, Meagher L, Heng TSP. Biological Considerations in Scaling Up Therapeutic Cell Manufacturing. Front Pharmacol 2020; 11:654. [PMID: 32528277 PMCID: PMC7247829 DOI: 10.3389/fphar.2020.00654] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/22/2020] [Indexed: 12/12/2022] Open
Abstract
Cell therapeutics - using cells as living drugs - have made advances in many areas of medicine. One of the most clinically studied cell-based therapy products is mesenchymal stromal cells (MSCs), which have shown promising results in promoting tissue regeneration and modulating inflammation. However, MSC therapy requires large numbers of cells, the generation of which is not feasible via conventional planar tissue culture methods. Scale-up manufacturing methods (e.g., propagation on microcarriers in stirred-tank bioreactors), however, are not specifically tailored for MSC expansion. These processes may, in principle, alter the cell secretome, a vital component underlying the immunosuppressive properties and clinical effectiveness of MSCs. This review outlines our current understanding of MSC properties and immunomodulatory function, expansion in commercial manufacturing systems, and gaps in our knowledge that need to be addressed for effective up-scaling commercialization of MSC therapy.
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Affiliation(s)
- Darshana S Cherian
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Tejasvini Bhuvan
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, Australia
| | - Tracy S P Heng
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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12
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Michl TD, Hibbs B, Hyde L, Postma A, Tran DTT, Zhalgasbaikyzy A, Vasilev K, Meagher L, Griesser HJ, Locock KES. Bacterial membrane permeability of antimicrobial polymethacrylates: Evidence for a complex mechanism from super-resolution fluorescence imaging. Acta Biomater 2020; 108:168-177. [PMID: 32179195 DOI: 10.1016/j.actbio.2020.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 12/31/2022]
Abstract
Amphiphilic polymers bearing cationic moieties are an emerging alternative to traditional antibiotics given their broad-spectrum activity and low susceptibility to the development of resistance. To date, however, much remains unclear regarding their mechanism of action. Using functional assays (ATP leakage, cell viability, DNA binding) and super-high resolution structured illumination microscopy (OMX-SR) of fluorescently tagged polymers, we present evidence for a complex mechanism, involving membrane permeation as well as cellular uptake, interaction with intracellular targets and possible complexation with bacterial DNA. STATEMENT OF SIGNIFICANCE: This manuscript details the first study to systematically and directly investigate the mechanism of action of antimicrobial polymers, using super-resolution fluorescence imaging as well as functional assays. While many in the field cite membrane permeation as the sole mechanism underlying the activity of such polymers, we present evidence for multimodal actions including high cellular uptake and interaction with intracellular targets. It is also the first report to show competitive binding of antimicrobial polymers with bacterial DNA in a dose-dependent manner.
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Affiliation(s)
- Thomas D Michl
- School of Engineering, University of South Australia, Mawson Lakes Blvd, Mawson Lakes, SA 5095, Australia
| | - Ben Hibbs
- Materials Characterisation and Fabrication Platform, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Lauren Hyde
- Materials Characterisation and Fabrication Platform, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Almar Postma
- CSIRO Manufacturing, Research Way, Clayton, VIC 3168, Australia
| | - Dung Thuy Thi Tran
- School of Engineering, University of South Australia, Mawson Lakes Blvd, Mawson Lakes, SA 5095, Australia
| | - Aigerim Zhalgasbaikyzy
- School of Engineering, University of South Australia, Mawson Lakes Blvd, Mawson Lakes, SA 5095, Australia
| | - Krasimir Vasilev
- School of Engineering, University of South Australia, Mawson Lakes Blvd, Mawson Lakes, SA 5095, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3168, Australia
| | - Hans J Griesser
- Future Industries Institute, University of South Australia, Mawson Lakes Blvd, Mawson Lakes, SA 5095, Australia
| | - Katherine E S Locock
- CSIRO Manufacturing, Research Way, Clayton, VIC 3168, Australia; Department of Chemical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia.
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13
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Wang H, Evans D, Voelcker NH, Griesser HJ, Meagher L. Interfacial Forces at Layered Surfaces: Substrate Electrical Double-Layer Forces Acting through Ultrathin Polymer Coatings. Langmuir 2019; 35:11679-11689. [PMID: 31407904 DOI: 10.1021/acs.langmuir.9b02176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Manipulating the surface properties of materials via the application of coatings is a widely used strategy to achieve desired interfacial interactions, implicitly assuming that the interfacial forces of coated samples are determined exclusively by the surface properties of the coatings. However, interfacial interactions between materials and their environments operate over finite length scales. Thus, the question addressed in this study is whether interactions associated with bulk substrate materials could act through thin coatings or, conversely, how thick a coating needs to be to completely screen subsurface forces contributed by underlying substrates. Plasma polymer layers were deposited on silicon wafer substrates from ethanol vapor, with identical chemical composition, ultrasmooth surfaces, and varying thicknesses. Using colloid-probe atomic force microscopy, electrical double-layer forces were determined in solutions of various ionic strengths and fitted using the Derjaguin-Landau-Verwey-Overbeek theory. For the thicker ethanol plasma polymers, the fitted surface potentials reflected the presence of surface carboxylate groups and were invariant with thickness. In contrast, for coatings <18 nm thick, the surface potentials increased steadily with decreasing film thickness; the measured electrical double-layer forces contained contributions from both the coating and the substrate. Theoretical calculations were in agreement with this model. Thus, our observations indicate that the higher surface potential of the underlying SiO2 surface can influence the interactions between a colloid particle and the multilayer structure if coatings are sufficiently thin. Such superposition needs to be factored into the design of coatings aimed at the control of material interactions via surface forces.
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Affiliation(s)
- Hongfang Wang
- Future Industries Institute , University of South Australia , Mawson Lakes , South Australia 5095 , Australia
| | - Drew Evans
- Future Industries Institute , University of South Australia , Mawson Lakes , South Australia 5095 , Australia
| | - Nicolas H Voelcker
- Future Industries Institute , University of South Australia , Mawson Lakes , South Australia 5095 , Australia
- Department of Materials Science and Engineering , Monash University , Clayton , Victoria 3800 , Australia
- Monash Institute of Pharmaceutical Sciences, Monash University , 381 Royal Parade , Parkville , Victoria 3052 , Australia
| | - Hans J Griesser
- Future Industries Institute , University of South Australia , Mawson Lakes , South Australia 5095 , Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering , Monash University , Clayton , Victoria 3800 , Australia
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Duque-Sanchez L, Brack N, Postma A, Meagher L, Pigram PJ. Engineering the Biointerface of Electrospun 3D Scaffolds with Functionalized Polymer Brushes for Enhanced Cell Binding. Biomacromolecules 2018; 20:813-825. [DOI: 10.1021/acs.biomac.8b01427] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Lina Duque-Sanchez
- Centre for Materials and Surface Science and Department of Chemistry and Physics, La Trobe University, Melbourne, Victoria 3086, Australia
- CSIRO Manufacturing, Bayview Avenue, Clayton, Vic 3168, Australia
| | - Narelle Brack
- Centre for Materials and Surface Science and Department of Chemistry and Physics, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Almar Postma
- CSIRO Manufacturing, Bayview Avenue, Clayton, Vic 3168, Australia
| | - Laurence Meagher
- Monash Institute of Medical Engineering and Department of Materials Science and Engineering, Monash University, Clayton, Vic 3800, Australia
| | - Paul J. Pigram
- Centre for Materials and Surface Science and Department of Chemistry and Physics, La Trobe University, Melbourne, Victoria 3086, Australia
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15
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Duque-Sánchez L, Brack N, Postma A, Pigram PJ, Meagher L. Optimisation of grafting of low fouling polymers from three-dimensional scaffolds via surface-initiated Cu(0) mediated polymerisation. J Mater Chem B 2018; 6:5896-5909. [DOI: 10.1039/c8tb01828f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Well-controlled low fouling polymers brushes were grafted from the surface of biodegradable electrospun fibres for advanced tissue engineering applications.
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Affiliation(s)
- Lina Duque-Sánchez
- Centre for Materials and Surface Science and Department of Chemistry and Physics
- La Trobe University
- Melbourne
- Australia
- CSIRO Manufacturing
| | - Narelle Brack
- Centre for Materials and Surface Science and Department of Chemistry and Physics
- La Trobe University
- Melbourne
- Australia
| | | | - Paul J. Pigram
- Centre for Materials and Surface Science and Department of Chemistry and Physics
- La Trobe University
- Melbourne
- Australia
| | - Laurence Meagher
- Monash Institute of Medical Engineering and Department of Materials Science and Engineering
- Monash University
- Clayton
- Australia
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Rodda AE, Ercole F, Glattauer V, Nisbet DR, Healy KE, Dove AP, Meagher L, Forsythe JS. Controlling integrin-based adhesion to a degradable electrospun fibre scaffold via SI-ATRP. J Mater Chem B 2016; 4:7314-7322. [PMID: 32263733 DOI: 10.1039/c6tb02444k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While polycaprolactone (PCL) and similar polyesters are commonly used as degradable scaffold materials in tissue engineering and related applications, non-specific adsorption of environmental proteins typically precludes any control over the signalling pathways that are activated during cell adhesion to these materials. Here we describe the preparation of PCL-based fibres that facilitate cell adhesion through well-defined pathways while preventing adhesion via adsorbed proteins. Surface-initiated atom transfer radical polymerisation (SI-ATRP) was used to graft a protein-resistant polymer brush coating from the surface of fibres, which had been electrospun from a brominated PCL macroinitiator. This coating also provided alkyne functional groups for the attachment of specific signalling molecules via the copper-mediated azide-alkyne click reaction; in this case, a cyclic RGD peptide with high affinity for αvβ3 integrins. Mesenchymal stem cells were shown to attach to the fibres via the peptide, but did not attach in its absence, nor when blocked with soluble peptide, demonstrating the effective control of cell adhesion pathways.
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Affiliation(s)
- Andrew E Rodda
- Department of Materials Science and Engineering, and Monash Institute for Medical Engineering, Monash University, Wellington Rd, Clayton 3800, Victoria, Australia.
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17
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Styan KE, Easton CD, Weaver LG, Meagher L. One-Reactant Photografting of ATRP Initiators for Surface-Initiated Polymerization. Macromol Rapid Commun 2016; 37:1079-86. [PMID: 27145108 DOI: 10.1002/marc.201600059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/14/2016] [Indexed: 01/26/2023]
Abstract
Self-initiated photografting polymerization is used to couple the polymerizable initiator monomer 2-(2-chloropropanoyloxy)ethyl acrylate to a range of polymeric substrates. The technique requires only UV light to couple the initiator to surfaces. The initiator surface density can be varied by inclusion of a diluent monomer or via selection of initiator and irradiation parameters. The functionality of the initiator surface is demonstrated by subsequent surface-initiated atom transfer radical polymerization. Surfaces are characterized by x-ray photoelectron spectroscopy (XPS), ellipsometry, and atomic force microscopy (AFM), and UV-induced changes to the initiator are assessed by (1) H NMR and gel permeation chromatography (GPC). This is the first time this one-reactant one-step technique has been demonstrated for creating an initiator surface of variable density.
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Affiliation(s)
- Katie E Styan
- CSIRO Manufacturing, Bayview Ave, Clayton, VIC, 3168, Australia.,Cooperative Research Centre for Polymers, Notting Hill, VIC, 3168, Australia
| | | | - Lucy G Weaver
- CSIRO Food and Nutrition, 671 Sneydes Road, Werribee, VIC, 3030, Australia
| | - Laurence Meagher
- Monash Institute of Medical Engineering and the Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia
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18
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Qu Y, Locock K, Verma-Gaur J, Hay ID, Meagher L, Traven A. Searching for new strategies against polymicrobial biofilm infections: guanylated polymethacrylates kill mixed fungal/bacterial biofilms. J Antimicrob Chemother 2015; 71:413-21. [PMID: 26490013 DOI: 10.1093/jac/dkv334] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 09/14/2015] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVES Biofilm-related human infections have high mortality rates due to drug resistance. Cohabitation of diverse microbes in polymicrobial biofilms is common and these infections present additional challenges for treatment compared with monomicrobial biofilms. Here, we address this therapeutic gap by assessing the potential of a new class of antimicrobial agents, guanylated polymethacrylates, in the treatment of polymicrobial biofilms built by two prominent human pathogens, the fungus Candida albicans and the bacterium Staphylococcus aureus. METHODS We used imaging and quantitative methods to test the antibiofilm efficacy of guanylated polymethacrylates, a new class of drugs that structurally mimic antimicrobial peptides. We further compared guanylated polymethacrylates with first-line antistaphylococcal and anti-Candida agents used as combinatorial therapy against polymicrobial biofilms. RESULTS Guanylated polymethacrylates were highly effective as a sole agent, killing both C. albicans and S. aureus when applied to established polymicrobial biofilms. Furthermore, they outperformed multiple combinations of current antimicrobial drugs, with one of the tested compounds killing 99.98% of S. aureus and 82.2% of C. albicans at a concentration of 128 mg/L. The extracellular biofilm matrix provided protection, increasing the MIC of the polymethacrylates by 2-4-fold when added to planktonic assays. Using the C. albicans bgl2ΔΔ mutant, we implicate matrix polysaccharide β-1,3 glucan in the mechanism of protection. Data for two structurally distinct polymers suggest that this mechanism could be minimized through chemical optimization of the polymer structure. Finally, we demonstrate that a potential application for these polymers is in antimicrobial lock therapy. CONCLUSIONS Guanylated polymethacrylates are a promising lead for the development of an effective monotherapy against C. albicans/S. aureus polymicrobial biofilms.
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Affiliation(s)
- Yue Qu
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia Department of Microbiology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia Department of Infectious Diseases, The Alfred Hospital and Monash University, Melbourne, VIC 3000, Australia
| | | | - Jiyoti Verma-Gaur
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia
| | - Iain D Hay
- Department of Microbiology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia
| | - Laurence Meagher
- CSIRO Manufacturing Flagship, Clayton, VIC 3168, Australia Department of Materials Science and Monash Institute of Medical Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia
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Fairbanks BD, Gunatillake PA, Meagher L. Biomedical applications of polymers derived by reversible addition - fragmentation chain-transfer (RAFT). Adv Drug Deliv Rev 2015; 91:141-52. [PMID: 26050529 DOI: 10.1016/j.addr.2015.05.016] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/25/2015] [Accepted: 05/27/2015] [Indexed: 11/19/2022]
Abstract
RAFT- mediated polymerization, providing control over polymer length and architecture as well as facilitating post polymerization modification of end groups, has been applied to virtually every facet of biomedical materials research. RAFT polymers have seen particularly extensive use in drug delivery research. Facile generation of functional and telechelic polymers permits straightforward conjugation to many therapeutic compounds while synthesis of amphiphilic block copolymers via RAFT allows for the generation of self-assembled structures capable of carrying therapeutic payloads. With the large and growing body of literature employing RAFT polymers as drug delivery aids and vehicles, concern over the potential toxicity of RAFT derived polymers has been raised. While literature exploring this complication is relatively limited, the emerging consensus may be summed up in three parts: toxicity of polymers generated with dithiobenzoate RAFT agents is observed at high concentrations but not with polymers generated with trithiocarbonate RAFT agents; even for polymers generated with dithiobenzoate RAFT agents, most reported applications call for concentrations well below the toxicity threshold; and RAFT end-groups may be easily removed via any of a variety of techniques that leave the polymer with no intrinsic toxicity attributable to the mechanism of polymerization. The low toxicity of RAFT-derived polymers and the ability to remove end groups via straightforward and scalable processes make RAFT technology a valuable tool for practically any application in which a polymer of defined molecular weight and architecture is desired.
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Affiliation(s)
- Benjamin D Fairbanks
- CSIRO Manufacturing Flagship, Ian Wark Laboratories, Clayton, VIC 3168, Australia; Chemical and Biological Engineering, University of Colorado, Boulder, CO, USA 80309-0596.
| | | | - Laurence Meagher
- CSIRO Manufacturing Flagship, Ian Wark Laboratories, Clayton, VIC 3168, Australia; Monash Institute for Medical Engineering and Department of Materials Science and Engineering, Monash University, PO Box 69M, VIC, 3800, Australia.
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20
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Rodda AE, Ercole F, Glattauer V, Gardiner J, Nisbet DR, Healy KE, Forsythe JS, Meagher L. Low Fouling Electrospun Scaffolds with Clicked Bioactive Peptides for Specific Cell Attachment. Biomacromolecules 2015; 16:2109-18. [DOI: 10.1021/acs.biomac.5b00483] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Andrew E. Rodda
- Department of Materials Science and Engineering & Monash Institute of Medical Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia
- CSIRO Manufacturing
Flagship, Bayview Avenue, Clayton 3168, Victoria, Australia
- Cooperative Research
Centre for Polymers, 8 Redwood Drive, Notting Hill 3168, Victoria, Australia
| | - Francesca Ercole
- Department of Materials Science and Engineering & Monash Institute of Medical Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology,
Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, 381
Royal Parade, Parkville 3052, Victoria, Australia
| | - Veronica Glattauer
- CSIRO Manufacturing
Flagship, Bayview Avenue, Clayton 3168, Victoria, Australia
| | - James Gardiner
- CSIRO Manufacturing
Flagship, Bayview Avenue, Clayton 3168, Victoria, Australia
| | - David R. Nisbet
- School
of Engineering, The Australian National University, Canberra 0200, Australian Capital Territory, Australia
| | - Kevin E. Healy
- Departments
of Bioengineering and Materials Science and Engineering, University of California at Berkeley, Berkeley, California, United States
| | - John S. Forsythe
- Department of Materials Science and Engineering & Monash Institute of Medical Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia
| | - Laurence Meagher
- Department of Materials Science and Engineering & Monash Institute of Medical Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia
- CSIRO Manufacturing
Flagship, Bayview Avenue, Clayton 3168, Victoria, Australia
- Cooperative Research
Centre for Polymers, 8 Redwood Drive, Notting Hill 3168, Victoria, Australia
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21
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Rodda AE, Ercole F, Nisbet DR, Forsythe JS, Meagher L. Optimization of Aqueous SI-ATRP Grafting of Poly(Oligo(Ethylene Glycol) Methacrylate) Brushes from Benzyl Chloride Macroinitiator Surfaces. Macromol Biosci 2015; 15:799-811. [DOI: 10.1002/mabi.201400512] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/15/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Andrew E. Rodda
- Department of Materials Engineering; Monash University; Wellington Rd Clayton 3800 Victoria Australia
- CSIRO Materials Science and Engineering, Bayview Avenue, Clayton 3168, Victoria, Australia; and Cooperative Research Centre for Polymers; 8 Redwood Drive Notting Hill 3168 Victoria Australia
| | - Francesca Ercole
- Department of Materials Engineering; Monash University; Wellington Rd Clayton 3800 Victoria Australia
| | - David R. Nisbet
- School of Engineering; The Australian National University; Canberra 0200 Australian Capital Territory Australia
| | - John S. Forsythe
- Department of Materials Engineering; Monash University; Wellington Rd Clayton 3800 Victoria Australia
| | - Laurence Meagher
- CSIRO Materials Science and Engineering, Bayview Avenue, Clayton 3168, Victoria, Australia; and Cooperative Research Centre for Polymers; 8 Redwood Drive Notting Hill 3168 Victoria Australia
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22
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Wilson JT, Postma A, Keller S, Convertine AJ, Moad G, Rizzardo E, Meagher L, Chiefari J, Stayton PS. Enhancement of MHC-I antigen presentation via architectural control of pH-responsive, endosomolytic polymer nanoparticles. AAPS J 2014; 17:358-69. [PMID: 25501498 DOI: 10.1208/s12248-014-9697-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/01/2014] [Indexed: 11/30/2022]
Abstract
Protein-based vaccines offer a number of important advantages over organism-based vaccines but generally elicit poor CD8(+) T cell responses. We have previously demonstrated that pH-responsive, endosomolytic polymers can enhance protein antigen delivery to major histocompatibility complex class I (MHC-I) antigen presentation pathways thereby augmenting CD8(+) T cell responses following immunization. Here, we describe a new family of nanocarriers for protein antigen delivery assembled using architecturally distinct pH-responsive polymers. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize linear, hyperbranched, and core-crosslinked copolymers of 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA) and butyl methacrylate (BMA) that were subsequently chain extended with a hydrophilic N,N-dimethylacrylamide (DMA) segment copolymerized with thiol-reactive pyridyl disulfide (PDS) groups. In aqueous solution, polymer chains assembled into 25 nm micellar nanoparticles and enabled efficient and reducible conjugation of a thiolated protein antigen, ovalbumin. Polymers demonstrated pH-dependent membrane-destabilizing activity in an erythrocyte lysis assay, with the hyperbranched and cross-linked polymer architectures exhibiting significantly higher hemolysis at pH ≤ 7.0 than the linear diblock. Antigen delivery with the hyperbranched and cross-linked polymer architecture enhanced in vitro MHC-I antigen presentation relative to free antigen, whereas the linear construct did not have a discernible effect. The hyperbranched system elicited a four- to fivefold increase in MHC-I presentation relative to the cross-linked architecture, demonstrating the superior capacity of the hyperbranched architecture in enhancing MHC-I presentation. This work demonstrates that the architecture of pH-responsive, endosomolytic polymers can have dramatic effects on intracellular antigen delivery, and offers a promising strategy for enhancing CD8(+) T cell responses to protein-based vaccines.
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Affiliation(s)
- John T Wilson
- Department of Bioengineering, University of Washington, Box 355061, Seattle, Washington, 98195, USA
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Ghezzi M, Thickett SC, Telford AM, Easton CD, Meagher L, Neto C. Protein micropatterns by PEG grafting on Dewetted PLGA films. Langmuir 2014; 30:11714-11722. [PMID: 25195610 DOI: 10.1021/la5018592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The ability to control protein and cell positioning on a microscopic scale is crucial in many biomedical applications, such as single cell studies. We have developed and investigated the grafting of poly(ethylene glycol) (PEG) brushes onto poly(d,l-lactide-co-glycolide) (PLGA) thin films, which can be micropatterned by exploiting their spontaneous dewetting on top of polystyrene (PS) films. Dense PEG brushes with excellent protein repellence were achieved on PLGA by using cloud point grafting conditions, and selective adsorption of proteins on the micropatterned substrates was achieved by exploiting the different affinity protein adsorption onto the PEG brushes and the PS holes. PEG-grafted PLGA films showed better resistance against spontaneous degradation in buffer than bare PLGA films, due to passivation by the thin PEG coating. The simplicity of dewetting and subsequent grafting approaches, coupled with the ability to coat and pattern nonplanar substrates give rise to possible applications of PEG-grafted PLGA films in single cell studies and cell cultures for tissue engineering.
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Affiliation(s)
- Manuel Ghezzi
- School of Chemistry, The University of Sydney , Sydney, NSW 2006, Australia
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Fairbanks BD, Thissen H, Maurdev G, Pasic P, White JF, Meagher L. Inhibition of Protein and Cell Attachment on Materials Generated from N-(2-Hydroxypropyl) Acrylamide. Biomacromolecules 2014; 15:3259-66. [DOI: 10.1021/bm500654q] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Helmut Thissen
- CSIRO Manufacturing Flagship, Bayview Avenue, Clayton 3169 VIC, Australia
| | - George Maurdev
- CSIRO Manufacturing Flagship, Bayview Avenue, Clayton 3169 VIC, Australia
| | - Paul Pasic
- CSIRO Manufacturing Flagship, Bayview Avenue, Clayton 3169 VIC, Australia
| | - Jacinta F. White
- CSIRO Manufacturing Flagship, Bayview Avenue, Clayton 3169 VIC, Australia
| | - Laurence Meagher
- CSIRO Manufacturing Flagship, Bayview Avenue, Clayton 3169 VIC, Australia
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Abstract
AbstractHost-defense antimicrobial peptides (AMPs) are a promising lead in the search for novel antibiotics. Many of these peptides exhibit broad-spectrum antibacterial ability, low toxicity toward human cells, and little susceptibility to induction of bacterial resistance. Our research focuses on the development of synthetic polymers that are able to mimic the amphiphilic and cation-rich characteristics of AMPs. This derives bioactive polymers that retain the activity profile of AMPs while utilizing a construct that is less expensive and easier to produce and manipulate chemically. This review details structure–activity relationships (SARs) of a new class of arginine-rich, synthetic AMP mimicking polymers (SAMPs), the guanylated polymethacrylates. These are contrasted with those of amine-based polymers that are mimics of lysine-rich AMPs. The ideal composition for candidates for practical applications was identified as those containing guanidines as a cation source, having a low molecular weight and a low level of lipophilicity. This gave polymers with high potency against Gram-positive strains of bacteria (e.g., Staphylococcus epidermidis MIC = 10 μg/mL) and low toxicity towards human red blood cells (<4% hemolysis at given MIC). This work emphasizes the need to rationalize observed biological activities based not purely on the global lipophilic and cationic character of polymers but rather to consider the profound effect that specific pendant functional groups may have on the potency, selectivity, and mechanisms behind the action of antimicrobial polymers.
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Affiliation(s)
- Katherine E.S. Locock
- 1CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, VIC 3168, Australia
| | - Thomas D. Michl
- 2Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Hans J. Griesser
- 3Mawson Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Matthias Haeussler
- 1CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, VIC 3168, Australia
| | - Laurence Meagher
- 1CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, VIC 3168, Australia
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26
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Rodda AE, Meagher L, Nisbet DR, Forsythe JS. Specific control of cell–material interactions: Targeting cell receptors using ligand-functionalized polymer substrates. Prog Polym Sci 2014. [DOI: 10.1016/j.progpolymsci.2013.11.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Coad BR, Styan KE, Meagher L. One step ATRP initiator immobilization on surfaces leading to gradient-grafted polymer brushes. ACS Appl Mater Interfaces 2014; 6:7782-7789. [PMID: 24783968 DOI: 10.1021/am501052d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A method is described that allows potentially any surface to be functionalized covalently with atom transfer radical polymerization (ATRP) initiators derived from ethyl-2-bromoisobutyrl bromide in a single step. In addition, the initiator surface density was variable and tunable such that the thickness of polymer chain grafted from the surface varied greatly on the surfaces providing examples, across the surface of a substrate, of increased chain stretching due to the entropic nature of crowded polymer chains leading toward polymer brushes. An initiator gradient of increasing surface density was deposited by plasma copolymerization of an ATRP initiator (ethyl 2-bromoisobutyrate) and a non-ATRP reactive diluent molecule (ethanol). The deposited plasma polymer retained its chemical ability to surface-initiate polymerization reactions as exemplified by N,N'-dimethyl acrylamide and poly(ethylene glycol) methyl ether methacrylate polymerizations, illustrating linear and bottle-brush-like chains, respectively. A large variation in graft thickness was observed from the low to high chain-density side suggesting that chains were forced to stretch away from the surface interface--a consequence of entropic effects resulting from increased surface crowding. The tert-butyl bromide group of ethyl 2-bromoisobutyrate is a commonly used initiator in ATRP, so a method for covalent linkage to any substrate in a single step desirably simplifies the multistep surface activation procedures currently used.
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Affiliation(s)
- Bryan R Coad
- Mawson Institute, University of South Australia , Mawson Lakes SA 5095, Australia
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Locock KES, Michl TD, Stevens N, Hayball JD, Vasilev K, Postma A, Griesser HJ, Meagher L, Haeussler M. Antimicrobial Polymethacrylates Synthesized as Mimics of Tryptophan-Rich Cationic Peptides. ACS Macro Lett 2014; 3:319-323. [PMID: 35590739 DOI: 10.1021/mz5001527] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study describes a facile and high yielding route to two series of polymethacrylates inspired by the naturally occurring, tryptophan-rich cationic antimicrobial polymers. Appropriate optimization of indole content within each gave rise to polymers with high potency against Staphylococcus epidermidis (e.g., PGI-3 minimum inhibitory concentration (MIC) = 12 μg/mL) and the methicillin-resistant strain of Staphylococcus aureus (e.g., PGI-3 MIC = 47 μg/mL) with minimal toxicity toward human red blood cells. Future work will be directed toward understanding the cooperative roles that the cationic and indole pendant groups have for the mechanism of these polymers.
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Affiliation(s)
- Katherine E. S. Locock
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Thomas D. Michl
- Ian
Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Natalie Stevens
- Sansom
Institute, School of Pharmacy and Medical Sciences, University of South Australia, City East, South Australia 5000, Australia
| | - John D. Hayball
- Sansom
Institute, School of Pharmacy and Medical Sciences, University of South Australia, City East, South Australia 5000, Australia
| | - Krasimir Vasilev
- Mawson
Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Almar Postma
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Hans J. Griesser
- Mawson
Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Laurence Meagher
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Matthias Haeussler
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
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Abstract
This study compares three common laboratory methods, size-exclusion chromatography (SEC), (1)H nuclear magnetic resonance (NMR), and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), to determine the molecular weight of oligomeric cationic copolymers. The potential bias for each method was examined across a series of polymers that varied in molecular weight and cationic character (both choice of cation (amine versus guanidine) and relative proportion present). SEC was found to be the least accurate, overestimating Mn by an average of 140%, owing to the lack of appropriate cationic standards available, and the complexity involved in estimating the hydrodynamic volume of copolymers. MALDI-TOF approximated Mn well for the highly monodisperse (Đ < 1.1), low molecular weight (degree of polymerization (DP) <50) species but appeared unsuitable for the largest polymers in the series due to the mass bias associated with the technique. (1)H NMR was found to most accurately estimate Mn in this study, differing to theoretical values by only 5.2%. (1)H NMR end-group analysis is therefore an inexpensive and facile, primary quantitative method to estimate the molecular weight of oliogomeric cationic polymethacrylates if suitably distinct end-groups signals are present in the spectrum.
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Affiliation(s)
- Katherine E S Locock
- CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
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30
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Ercole F, Rodda AE, Meagher L, Forsythe JS, Dove AP. Surface grafted poly(ε-caprolactone) prepared using organocatalysed ring-opening polymerisation followed by SI-ATRP. Polym Chem 2014. [DOI: 10.1039/c3py01701j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The controlled ring-opening polymerisation (ROP) of an ATRP initiator-containing lactone, γ-BMPCL, and its copolymerisation with ε-caprolactone is reported. One resulting copolymer was successfully used as a substrate for surface initiated ATRP to produce surface-grafted poly(oligo(ethylene glycol) methacrylate) brushes.
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Affiliation(s)
- Francesca Ercole
- Department of Materials Engineering
- Monash University
- Clayton
- Australia
| | - Andrew E. Rodda
- Department of Materials Engineering
- Monash University
- Clayton
- Australia
- CSIRO
| | - Laurence Meagher
- CSIRO
- Materials Science and Engineering
- Clayton
- Australia
- Cooperative Research Centre for Polymers (CRCP)
| | - John S. Forsythe
- Department of Materials Engineering
- Monash University
- Clayton
- Australia
| | - Andrew P. Dove
- Department of Materials Engineering
- Monash University
- Clayton
- Australia
- Department of Chemistry
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31
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Michl TD, Locock KES, Stevens NE, Hayball JD, Vasilev K, Postma A, Qu Y, Traven A, Haeussler M, Meagher L, Griesser HJ. RAFT-derived antimicrobial polymethacrylates: elucidating the impact of end-groups on activity and cytotoxicity. Polym Chem 2014. [DOI: 10.1039/c4py00652f] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We report the use of RAFT polymerization to obtain eight cationic methacrylate polymers bearing amine or guanidine pendant groups, while varying the R- and Z-RAFT end-groups.
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Affiliation(s)
- Thomas D. Michl
- Ian Wark Research Institute
- University of South Australia
- Mawson Lakes, Australia
| | | | - Natalie Emilia Stevens
- Sansom Institute
- School of Pharmacy and Medical Sciences
- University of South Australia
- City East, Australia
| | - John D. Hayball
- Sansom Institute
- School of Pharmacy and Medical Sciences
- University of South Australia
- City East, Australia
| | - Krasimir Vasilev
- Mawson Institute
- University of South Australia
- Mawson Lakes, Australia
| | - Almar Postma
- CSIRO Materials Science and Engineering
- Clayton, Australia
| | - Yue Qu
- Department of Biochemistry and Molecular Biology
- Monash University
- Clayton, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology
- Monash University
- Clayton, Australia
| | | | | | - Hans J. Griesser
- Mawson Institute
- University of South Australia
- Mawson Lakes, Australia
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Ameringer T, Ercole F, Tsang KM, Coad BR, Hou X, Rodda A, Nisbet DR, Thissen H, Evans RA, Meagher L, Forsythe JS. Surface grafting of electrospun fibers using ATRP and RAFT for the control of biointerfacial interactions. Biointerphases 2013; 8:16. [DOI: 10.1186/1559-4106-8-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 06/20/2013] [Indexed: 11/10/2022] Open
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Lambshead JW, Meagher L, O'Brien C, Laslett AL. Defining synthetic surfaces for human pluripotent stem cell culture. Cell Regen (Lond) 2013; 2:7. [PMID: 25408879 PMCID: PMC4230363 DOI: 10.1186/2045-9769-2-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 11/19/2013] [Indexed: 12/29/2022]
Abstract
Human pluripotent stem cells (hPSCs) are able to self-renew indefinitely and to differentiate into all adult cell types. hPSCs therefore show potential for application to drug screening, disease modelling and cellular therapies. In order to meet this potential, culture conditions must be developed that are consistent, defined, scalable, free of animal products and that facilitate stable self-renewal of hPSCs. Several culture surfaces have recently been reported to meet many of these criteria although none of them have been widely implemented by the stem cell community due to issues with validation, reliability and expense. Most hPSC culture surfaces have been derived from extracellular matrix proteins (ECMPs) and their cell adhesion molecule (CAM) binding motifs. Elucidating the CAM-mediated cell-surface interactions that are essential for the in vitro maintenance of pluripotency will facilitate the optimisation of hPSC culture surfaces. Reports indicate that hPSC cultures can be supported by cell-surface interactions through certain CAM subtypes but not by others. This review summarises the recent reports of defined surfaces for hPSC culture and focuses on the CAMs and ECMPs involved.
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Affiliation(s)
- Jack W Lambshead
- CSIRO Materials Science and Engineering, Clayton, Victoria 3168 Australia ; Australian Regenerative Medicine Institute, Monash University, Kragujevac, Victoria 3800 Australia
| | - Laurence Meagher
- CSIRO Materials Science and Engineering, Clayton, Victoria 3168 Australia
| | - Carmel O'Brien
- CSIRO Materials Science and Engineering, Clayton, Victoria 3168 Australia ; Australian Regenerative Medicine Institute, Monash University, Kragujevac, Victoria 3800 Australia
| | - Andrew L Laslett
- CSIRO Materials Science and Engineering, Clayton, Victoria 3168 Australia ; Australian Regenerative Medicine Institute, Monash University, Kragujevac, Victoria 3800 Australia ; Department of Zoology, University of Melbourne, Parkville, Victoria 3101 Australia
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34
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Locock KES, Michl TD, Valentin JDP, Vasilev K, Hayball JD, Qu Y, Traven A, Griesser HJ, Meagher L, Haeussler M. Guanylated Polymethacrylates: A Class of Potent Antimicrobial Polymers with Low Hemolytic Activity. Biomacromolecules 2013; 14:4021-31. [DOI: 10.1021/bm401128r] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Katherine E. S. Locock
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Thomas D. Michl
- Ian
Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Jules D. P. Valentin
- Mawson
Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Krasimir Vasilev
- Mawson
Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - John D. Hayball
- Sansom
Institute, School of Pharmacy and Medical Sciences, University of South Australia, City East, South Australia 5000, Australia
| | - Yue Qu
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Ana Traven
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Hans J. Griesser
- Ian
Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Laurence Meagher
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Matthias Haeussler
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
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35
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36
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Tarasova A, Haylock DN, Meagher L, Be CL, White J, Nilsson SK, Andrade J, Cartledge K, Winkler DA. Potent Agonists of a Hematopoietic Stem Cell Cytokine Receptor, c-Mpl. ChemMedChem 2013; 8:763-71. [DOI: 10.1002/cmdc.201300089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Indexed: 11/12/2022]
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37
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Riches AG, Cablewski T, Glattauer V, Thissen H, Meagher L. Scalable synthesis of an integrin-binding peptide mimetic for biomedical applications. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Telford AM, Meagher L, Glattauer V, Gengenbach TR, Easton CD, Neto C. Micropatterning of Polymer Brushes: Grafting from Dewetting Polymer Films for Biological Applications. Biomacromolecules 2012; 13:2989-96. [DOI: 10.1021/bm3010534] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. M. Telford
- School of Chemistry, The University of Sydney, F11, NSW 2006
Australia
- CSIRO Future Manufacturing National Research Flagship, Clayton, Victoria 3168,
Australia
| | - L. Meagher
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria
3169, Australia
| | - V. Glattauer
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria
3169, Australia
| | - T. R. Gengenbach
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria
3169, Australia
| | - C. D. Easton
- CSIRO Materials Science and Engineering, Bag 10, Clayton South, Victoria
3169, Australia
| | - C. Neto
- School of Chemistry, The University of Sydney, F11, NSW 2006
Australia
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39
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Coad BR, Lu Y, Glattauer V, Meagher L. Substrate-independent method for growing and modulating the density of polymer brushes from surfaces by ATRP. ACS Appl Mater Interfaces 2012; 4:2811-2823. [PMID: 22512463 DOI: 10.1021/am300463q] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We describe a method for grafting PEG-based polymer chains of variable surface density using a substrate independent approach, allowing grafting from virtually any material substrate. The approach relies upon initial coupling of a macroinitiator to plasma polymer treated surfaces. The macroinitiator is a novel random terpolymer containing ATRP initiator residues, strongly negatively charged groups, and carboxylic acid moieties that facilitate covalent surface anchoring. Surface-initiated ATRP (SI-ATRP) using polyethylene glycol methyl ether methacrylate (PEGMA) at different concentrations led to grafted surfaces of controlled thickness in either the "brush" or "mushroom" morphology, which was controlled by the abundance of initiator residues in the macroinitiator. Grafted polymer layer structure was investigated via direct interaction force measurements using colloid probe atomic force microscopy (AFM). Equilibrium, hydrated graft layer thicknesses inferred from the highly repulsive AFM force data suggest that the polymer brush graft layer contained polymer chains which were fully stretched. Since the degree of stretching resulted in layer thicknesses approaching the polymer contour length, the polymer brushes studied must be very close to maximum graft density. Grafted layers where the polymer molecules were in the mushroom regime resulted in much thinner layers but the chains had greater chain entropic freedom as indicated by strongly attractive bridging interactions between tethered chains and the silica colloid probe. Use of this experimental methodology would be suitable for preparing grafted polymer layers of a preferred density free from substrate-specific linking chemistries.
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Affiliation(s)
- Bryan R Coad
- CSIRO Materials Science and Engineering, Clayton, Victoria, Australia.
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40
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Coad BR, Lu Y, Meagher L. A substrate-independent method for surface grafting polymer layers by atom transfer radical polymerization: reduction of protein adsorption. Acta Biomater 2012; 8:608-18. [PMID: 22023749 DOI: 10.1016/j.actbio.2011.10.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/31/2011] [Accepted: 10/05/2011] [Indexed: 11/25/2022]
Abstract
A general method for producing low-fouling biomaterials on any surface by surface-initiated grafting of polymer brushes is presented. Our procedure uses radiofrequency glow discharge thin film deposition followed by macro-initiator coupling and then surface-initiated atom transfer radical polymerization (SI-ATRP) to prepare neutral polymer brushes on planar substrates. Coatings were produced on substrates with variable interfacial composition and mechanical properties such as hard inorganic/metal substrates (silicon and gold) or flexible (perfluorinated poly(ethylene-co-propylene) film) and rigid (microtitre plates) polymeric materials. First, surfaces were functionalized via deposition of an allylamine plasma polymer thin film followed by covalent coupling of a macro-initiator composed partly of ATRP initiator groups. Successful grafting of a hydrophilic polymer layer was achieved by SI-ATRP of N,N'-dimethylacrylamide in aqueous media at room temperature. We exemplified how this method could be used to create surface coatings with significantly reduced protein adsorption on different material substrates. Protein binding experiments using labelled human serum albumin on grafted materials resulted in quantitative evidence for low-fouling compared to control surfaces.
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41
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Ameringer T, Fransen P, Bean P, Johnson G, Pereira S, Evans RA, Thissen H, Meagher L. Polymer coatings that display specific biological signals while preventing nonspecific interactions. J Biomed Mater Res A 2011; 100:370-9. [PMID: 22076848 DOI: 10.1002/jbm.a.33194] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 05/24/2011] [Accepted: 05/25/2011] [Indexed: 01/14/2023]
Abstract
Control over cell-material surface interactions is the key to many new and improved biomedical devices. It can only be achieved if interactions that are mediated by nonspecifically adsorbed serum proteins are minimized and if cells instead respond to specific ligand molecules presented on the surface. Here, we present a simple yet effective surface modification method that allows for the covalent coupling and presentation of specific biological signals on coatings which have significantly reduced nonspecific biointerfacial interactions. To achieve this we synthesized bottle brush type copolymers consisting of poly(ethylene glycol) methyl ether methacrylate and (meth)acrylates providing activated NHS ester groups as well as different spacer lengths between the NHS groups and the polymer backbone. Copolymers containing different molar ratios of these monomers were grafted to amine functionalized polystyrene cell culture substrates, followed by the covalent immobilization of the cyclic peptides cRGDfK and cRADfK using residual NHS groups. Polymers were characterized by GPC and NMR and surface modification steps were analyzed using XPS. The cellular response was evaluated using HeLa cell attachment experiments. The results showed strong correlations between the effectiveness of the control over biointerfacial interactions and the polymer architecture. They also demonstrate that optimized fully synthetic copolymer coatings, which can be applied to a wide range of substrate materials, provide excellent control over biointerfacial interactions.
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Affiliation(s)
- Thomas Ameringer
- CSIRO Materials Science and Engineering, Bayview Avenue, Clayton VIC 3168, Australia; Cooperative Research Centre for Polymers (CRCP), 8 Redwood Drive, Notting Hill VIC 3168, Australia.
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42
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McCreesh K, Arthurs S, Horgan S, Keane L, Meagher L. Vehicle head restraint positioning knowledge and behaviours in a sample of Irish drivers. Int J Inj Contr Saf Promot 2011; 19:340-6. [PMID: 22046950 DOI: 10.1080/17457300.2011.628754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
A correctly positioned vehicle head restraint (HR) can reduce whiplash injury risk in collisions, however, HRs are often sub-optimally positioned. The primary aim of this study was to investigate vehicle HR position and driver knowledge of correct HR positioning in an Irish population. Secondary aims were to investigate the associations with driver age, gender and vehicle age. Data collection involved HR measurement and a driver questionnaire (n = 110). Just 27% of drivers had optimal HR positioning, while 30% had poor or marginal positioning. Newer vehicles (<5 years old) had better positioned HR in the horizontal plane (p = 0.036), than older vehicles. Younger drivers (<30 years) were more likely to have poorer positioning of HR (p = 0.002), than the 30 years or over group. Females were more likely to have better vertical positioning of their HR (p = 0.003) than males. Driver knowledge of correct position was variable, and not associated with actual HR position, with 65% knowing the correct vertical positioning standard but only 27% identifying the correct horizontal position. Many drivers have inadequately positioned HR, which needs to be addressed by improved vehicle design and public education.
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Affiliation(s)
- K McCreesh
- Department of Physiotherapy, University of Limerick, Limerick, Ireland.
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43
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Willcox MDP, Phillips B, Ozkan J, Jalbert I, Meagher L, Gengenbach T, Holden B, Papas E. Interactions of lens care with silicone hydrogel lenses and effect on comfort. Optom Vis Sci 2010; 87:839-46. [PMID: 20818281 DOI: 10.1097/opx.0b013e3181f3e2fc] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The purpose of this study was to investigate the effect of lens care products on short-term subjective and physiological performance silicone hydrogel lenses. METHODS Ten subjects wore either lotrafilcon B or galyfilcon A silicone hydrogel contact lenses soaked in a lens care product containing either Polyquad/Aldox or PHMB or control lenses inserted directly from the pack. Subjects wore the lenses for 6 h. Ocular comfort (graded on a 1 to 10 scale) and ocular physiology were assessed. Unworn but soaked lenses were analyzed for metrological changes, release of excipients into phosphate buffered saline, and changes to their surface chemical composition. RESULTS None of the lens metrology measures or clinically observed conjunctival or limbal redness changed. Corneal staining was significantly (p < 0.008) raised, albeit to low levels, after 6 h wear for either lens type when soaked in the PHMB solution compared with the control lens (lotrafilcon B 0.4 to 0.9 ± 0.7 to 0.4 vs. 0.1 to 0.4 ± 0.3 to 0.5; galyfilcon A 0.2 to 0.3 ± 0.2 to 0.4 vs. 0.0 ± 0.0). For lotrafilcon B lenses, there were decreases in comfort (p = 0.002), increases in burning/stinging (p = 0.002) after 1 h of wear, and increases in lens awareness on lens insertion (p = 0.0001) when soaked in PHMB. However, lotrafilcon B lenses soaked in Polyquad/Aldox showed increases in burning/stinging after 1 and 6 h (p < 0.008) of lens wear. For galyfilcon A lenses, most significant (p ≤ 0.002) changes to symptomatology occurred after soaking in Polyquad/Aldox solution. More PHMB was released from lotrafilcon B lenses, and more MPDS material was released from galyfilcon A lenses. The surface of galyfilcon A lenses changed but irrespective of lens solution type, whereas the changes to the lens surface was dependent on solution type for lotrafilcon B lenses. CONCLUSIONS Lens care products can change corneal staining and comfort responses during wear. These changes may be associated with release of material soaked into lenses or changes to the lens surface composition.
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Affiliation(s)
- Mark D P Willcox
- Brien Holden Vision Institute, The University of New South Wales, Sydney, New South Wales, Australia.
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44
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Andrade J, Cablewski T, Condie G, Haylock D, Meagher L, Riches A, Tarasova A, Werkmeister J, White J, Winkler D. Zinc is not required for activity of TPO agonists acting at the c-Mpl receptor transmembrane domain. ACS Chem Biol 2010; 5:741-5. [PMID: 20536264 DOI: 10.1021/cb100100u] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecules that mimic the cytokine thrombopoietin that act by an atypical mechanism of binding to a receptor transmembrane (TM) domain are widely understood to require zinc for their biological activity. We investigated potent thrombopoietin mimetics from three chemical classes including the recently registered drug Eltrombopag, which operate via this novel mechanism, to determine whether zinc is essential for inducing cell proliferation. Using addition of zinc and a potent metal chelator, we show that the existing paradigm is incorrect and the compounds exhibit excellent thrombopoietin-mimetic activity even in the presence of high concentrations of EDTA. The implications of these findings for the mechanism of action are discussed.
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Affiliation(s)
- Jessica Andrade
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
- The Australian Stem Cell Centre, PO Box 8002, Monash University LPO, Vic 3168, Australia
| | - Teresa Cablewski
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - Glenn Condie
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - David Haylock
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
- The Australian Stem Cell Centre, PO Box 8002, Monash University LPO, Vic 3168, Australia
| | - Laurence Meagher
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - Andrew Riches
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - Anna Tarasova
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - Jerome Werkmeister
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - Jacinta White
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
| | - David Winkler
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Vic 3169, Australia
- CRC for Polymers, Redwood Drive, Notting Hill, Vic 3168, Australia
- Monash Institute for Pharmaceutical Sciences, 381 Royal Parade, Parkville 3052, Australia
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Telford AM, James M, Meagher L, Neto C. Thermally cross-linked PNVP films as antifouling coatings for biomedical applications. ACS Appl Mater Interfaces 2010; 2:2399-2408. [PMID: 20735114 DOI: 10.1021/am100406j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Protein repellent coatings are widely applied to biomedical devices in order to reduce the nonspecific adhesion of plasma proteins, which can lead to failure of the device. Poly(N-vinylpyrrolidone) (PNVP) is a neutral, hydrophilic polymer with outstanding antifouling properties often used in these applications. In this paper, we characterize for the first time a cross-linking mechanism that spontaneously occurs in PNVP films upon thermal annealing. The degree of cross-linking of PNVP films and their solubility in water can be tailored by controlling the annealing, with no need for additional chemical treatment or irradiation. The physicochemical properties of the cross-linked films were investigated by X-ray photoelectron spectroscopy, infrared spectroscopy, neutron and X-ray reflectometry, ellipsometry, and atomic force microscopy, and a mechanism for the thermally induced cross-linking based on radical formation was proposed. The treated films are insoluble in water and robust upon immersion in harsh acid environment, and maintain the excellent protein-repellent properties of unmodified PNVP, as demonstrated by testing fibrinogen and immunoglobulin G adsorption with a quartz crystal microbalance. Thermal cross-linking of PNVP films could be exploited in a wide range of biotechnological applications to give antifouling properties to objects of any size, essentially making this an alternative to high-tech surface modification techniques.
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Affiliation(s)
- Andrew M Telford
- School of Chemistry, Building F11, The University of Sydney, New South Wales 2006, Australia
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Thissen H, Gengenbach T, du Toit R, Sweeney DF, Kingshott P, Griesser HJ, Meagher L. Clinical observations of biofouling on PEO coated silicone hydrogel contact lenses. Biomaterials 2010; 31:5510-9. [DOI: 10.1016/j.biomaterials.2010.03.040] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 03/17/2010] [Indexed: 10/19/2022]
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Hamilton-Brown P, Gengenbach T, Griesser HJ, Meagher L. End terminal, poly(ethylene oxide) graft layers: surface forces and protein adsorption. Langmuir 2009; 25:9149-9156. [PMID: 19534458 DOI: 10.1021/la900703e] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Covalently grafted poly(ethylene oxide) coatings have been widely studied for use in biomedical applications, particularly for the reduction of protein and other biomolecule adsorption. However, many of these studies have not characterized the hydrated structure of the coatings. This new study uses a combination of silica colloid probe interaction force measurements using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) in order to determine the grafting density and hydrated layer structure of monomethoxy poly(ethylene oxide) aldehyde layers, covalently grafted onto amine plasma polymer surfaces, and their interactions with silica surfaces. For high grafting densities, purely repulsive interactions were measured as expected for densely grafted polymer brushes. These interactions could be described by theoretical expectations for compression of one polymer brush layer. However, at lower grafting densities, attractive interactions were observed at larger separation distances, originating from bridging interactions due to adsorption of the PEO chains on the surface of the silica colloid probe. This is a new finding indicating that the coupled PEO molecules have sufficient conformational freedom to interact strongly with an adjacent surface or, for example, protein molecules for which there is an affinity. The attractive interactions could be removed by grafting an additional PEO layer onto the silica colloid probe. Protein adsorption measurements confirmed that at high grafting densities, the amount of adsorbed protein on the PEO grafted surfaces was greatly reduced, to the order of the detection limit for the XPS technique.
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Affiliation(s)
- Paul Hamilton-Brown
- CSIRO Molecular and Health Technologies, Bag 10, Clayton South, Victoria 3169, Australia
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48
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Abstract
Liposomes that are surface-bound to a biomaterial such as a contact lens are of interest for localized delivery of therapeutic agents, but it is not known whether such liposome layers are sufficiently robust. The stability of a dense, PEG-functionalized layer of liposomes, affinity-bound onto a multilayer coated surface, was tested under various stress conditions using colloid-probe atomic force miscroscopy (AFM). The different stress effects were generated by varying the applied normal load of the probe and the impinging fluid shear through different approach velocities and by varying the applied lateral forces by scanning under increasing force loads. The effect of applied forces (normal and lateral) was further investigated by coating the probe with a layer of albumin. The liposomes remained intact following the ramping of both protein-coated and uncoated probes under the normal and lateral loads. The low-fouling nature of these liposomes, with respect to nonspecific protein adsorption, was also demonstrated from the interaction force measurements which showed only weak adhesion from the protein layer during the contact period of the albumin-coated probe. The observed adhesive interactions were concluded to be a direct result of the applied load from the probe, during the force measurements, rather than from attraction of the protein molecules for the surface-bound liposomes. The low frictional response of the liposome layer indicated the viscoelastic nature of these molecules, which enabled liposome structure retention during the continuous load application. The demonstrated stability of the liposomes presents a system of viable and localized drug delivery in, for example, ophthalmic applications.
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Affiliation(s)
- Anna Tarasova
- CSIRO Molecular and Health Technologies, Bag 10, Bayview Avenue, Clayton, Victoria 3168, Australia.
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Muir BW, Tarasova A, Gengenbach TR, Menzies DJ, Meagher L, Rovere F, Fairbrother A, McLean KM, Hartley PG. Characterization of low-fouling ethylene glycol containing plasma polymer films. Langmuir 2008; 24:3828-3835. [PMID: 18307364 DOI: 10.1021/la702689t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Low-protein-fouling poly(ethylene glycol) (PEG-like) plasma polymer films were prepared using radio frequency glow discharge polymerization of diethylene glycol dimethyl ether (DGpp) on top of a heptylamine plasma polymer primer layer. By varying the plasma deposition conditions, the chemistry of the DGpp film was influenced, especially in regard to the level of ether content, which in turn influenced the relative levels of bovine serum albumin and lysozyme protein fouling. Surface potential measurements indicated that these surfaces carried a net negative charge. While protein fouling remained low ( approximately 10 ng/cm2), there was a slightly higher level of the positively charged protein adsorbed on these films than the negative protein. The interaction forces measured between a silica spherical surface on both "high"- and "low"-protein-fouling DGpp films were all repulsive and short ranged (2-3 nm). There was no correlation between the surface forces measured for high- and low-protein-fouling DGpp films. Thus, it appears that enthalpic effects are very important in reducing protein adsorption. We therefore conclude that it is the concentration of residual, ethylene glycol containing species that are the crucial parameter determining protein resistance due to a combination of both entropic and enthalpic effects.
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Affiliation(s)
- Benjamin W Muir
- CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton 3168, Australia.
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Finbow ME, Buultjens TE, John S, Kam E, Meagher L, Pitts JD. Molecular structure of the gap junctional channel. Ciba Found Symp 2007; 125:92-107. [PMID: 3030674 DOI: 10.1002/9780470513408.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The proteins in various gap junctional preparations from rodent liver have been analysed by two-dimensional peptide mapping and immunoblotting. Only the protein of relative molecular mass (Mr) 16,000 (16K) is found in all gap junctional isolates, and it is unrelated to the 27K protein. The absence of the 27K protein and any of its fragments from trypsin-treated preparations suggests that this protein does not directly contribute to gap junctional structure. Peptide mapping and immunoblotting of the 16K proteins isolated from various tissues and species and of the arthropod 18K protein present in gap junctional preparations from Nephrops norvegicus show that these proteins constitute a family of related junctional proteins. A site-specific antiserum raised against the N-terminal octapeptide of the 16K protein from mouse liver cross-reacts with all 16K and 18K forms of the junctional protein so far tested, suggesting that this particular antigenic determinant is highly conserved. Immuno-localization studies show that the N-terminus is most likely located on the cytoplasmic aspect of the junction and is available to Pronase digestion.
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