Professor Gwendolen Reilly
DPhil, BSc
School of Chemical, Materials and Biological Engineering
School of Chemical, Materials and Biological Engineering
Professor of Musculoskeletal Bioengineering
+44 114 222 5986
Full contact details
School of Chemical, Materials and Biological Engineering
Pam Liversidge Building
Mappin Street
葫芦影业
S1 3JD
- Profile
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Gwendolen Reilly has been a member of academic staff since 2004.
She received her DPhil in Biology at the University of York, specialising in bone biomechanics. She has previously undertaken post-doctoral research at the University of Pennsylvania, Pennsylvania State College of Medicine and the Swiss Federal Institute of Technology in cell biomechanics, biomaterials and bone structure respectively. Subsequently, she undertook a position as Research Assistant Professor in Bioengineering at the University of Illinois, Chicago specializing in tissue engineering.
Gwen鈥檚 current research combines her expertise in biomechanics, biomaterials and orthopaedics.
- Research interests
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The research has applications in orthopaedic and dental medicine, where clinicians are looking for improved methods to repair skeletal tissues; bone, tendon and cartilage.
Bone tissue engineering
The aim of bone tissue engineering is to create bone matrix in the laboratory for clinical implantation and as an experimental tool. Our research in this area focuses on two main themes; the effects of mechanical stimulation on differentiation and matrix formation by bone cells and the interactions between precursor bone cells and their biomaterial substrate. Mechanical stimuli examined include dynamic compression, stretch and fluid flow induced shear stresses using a range of bioreactors (including a collaboration with ElectroForce systems group).Musculoskeletal cell mechanobiology
We are interested in how skeletal cells respond to extrinsic and intrinsic stimuli by organizing the proteins and mineral they secrete in a way which enhances the strength of the matrix. This information can then be used to manipulate tissue-engineered structures in order to induce structurally sound matrix formation. We specifically focus on mechanosensation mechanisms found on the cell membrane; the cell鈥檚 proteoglycan (sugar-based) coat and a small organelle that protrudes from the cell membrane 鈥 the primary cilia.Orthopaedic biomaterials
We investigate the interactions between musculoskeletal cells and orthopaedic and dental materials that are implanted into bone. Materials investigated include porous metals, polymer scaffolds and peptide coated surfaces (in collaboration with Orla Protein Technologies). This research encompasses the study of the mechanical properties of biomaterial scaffolds, cell-material interactions, cell mechanics and cell signalling.
- Publications
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Journal articles
- . J Mater Chem B.
- . Bone Reports, 22, 101795-101795.
- . Heliyon, 10(7), e29150-e29150.
- . Frontiers in Chemistry, 11.
- . International Journal of Molecular Sciences, 23(18).
- . Vacuum, 203.
- . Genes & Nutrition, 17(1).
- . Frontiers in Bioengineering and Biotechnology, 9.
- . Journal of the Mechanical Behavior of Biomedical Materials.
- . International Journal of Bioprinting, 6(2), 99-113.
- . ACS Applied Materials & Interfaces, 12(11), 12510-12524.
- . Materials & Design, 188.
- . Biomedical Physics & Engineering Express, 6(2).
- . Marine Drugs, 18(2).
- . Bioengineering, 7(1).
- . Frontiers in Bioengineering and Biotechnology, 7.
- . Journal of Bone and Mineral Research.
- . Materials, 12(16), 2643-2643.
- . Polymer, 175, 243-254.
- . Journal of the Mechanical Behavior of Biomedical Materials, 94, 259-266.
- . Journal of the Mechanical Behavior of Biomedical Materials, 96, 193-203.
- . Journal of the Mechanical Behavior of Biomedical Materials, 90, 20-29.
- . Scientific Reports, 8(1).
- . PLoS ONE, 13(10).
- . Materials & Design, 156, 494-503.
- . Front Bioeng Biotechnol, 6, 134-134.
- . APL Bioengineering.
- . Journal of Tissue Engineering and Regenerative Medicine, 12(2), 370-381.
- . PLoS ONE, 13(1).
- . J Biomed Mater Res A.
- . Applied Biochemistry and Biotechnology, 185(2), 555-563.
- . Scientific Reports, 7.
- . Journal of Materials Research, 32(20), 3811-3821.
- . Journal of Materials Science: Materials in Medicine, 28(2).
- . Frontiers in Bioengineering and Biotechnology, 4.
- . Bone.
- . Biotechnology and Bioengineering, 113(8), 1814-1824.
- . Polymers, 8(6), 221-229.
- . Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 230(8), 761-774.
- . Metals, 6(5), 97-97.
- . Journal of the Mechanical Behavior of Biomedical Materials, 54, 159-172.
- . Data in Brief, 5, 616-620.
- . Biomaterials, 52, 140-147.
- . Journal of Biomechanics, 48(10), 2034-2040.
- . Biomacromolecules, 16(1), 66-75.
- . World Journal of Stem Cells, 7(3), 568-568.
- . Journal of the Mechanical Behavior of Biomedical Materials, 39, 95-110.
- . PLoS One, 9(2), e89761.
- . Bio-Medical Materials and Engineering, 24(5), 1803-1815.
- . RSC Advances, 4(25), 12630-12639.
- . FASEB J, 28(1), 430-439.
- . Biomaterials Science, 1(9), 942-951.
- . Journal of Biomedical Materials Research - Part B Applied Biomaterials, 101 B(6), 939-949.
- . Strain.
- . Journal of Biomechanics, 45, S655-S655.
- . J Biomed Mater Res A, 100(11), 2948-2959.
- Mesenchymal stem cell responses to mechanical stimuli. Muscles, Ligaments and Tendons Journal, 2, 169-180.
- . Eur Cell Mater, 24, 162-174.
- . J Biomech, 45(3), 549-554.
- . International Journal of Surgery, 9(7), 556-556.
- . Procedia Engineering, 13, 422-427.
- Degradation, Bioactivity, and Osteogenic Potential of Composites Made of PLGA and Two Different Sol-Gel Bioactive Glasses. Annals of Biomedical Engineering, 1-16.
- . Regenerative Medicine, 5(5), 713-724.
- . SOFT MATTER, 6(18), 4466-4470.
- . IFMBE Proceedings, 31 IFMBE, 926-929.
- . P I MECH ENG H, 224(H12), 1509-1521.
- , 43(1), 55-62.
- . JOURNAL OF MATERIALS SCIENCE: MATERIALS IN MEDICINE, 21(5), 1761-1769.
- . Macromolecular Bioscience, 10(8), 887-897.
- SHORT BOUTS OF MECHANICAL LOADING ARE AS EFFECTIVE AS DEXAMETHASONE AT INDUCING MATRIX PRODUCTION BY HUMAN BONE MARROW MESENCHYMAL STEM CELLS. EUR CELLS MATER, 20, 45-57.
- Nanoscopic mechanical anisotropy in hydrogel surfaces (vol 6, pg 4466, 2010). SOFT MATTER, 6(24), 6211-6211.
- Development of a Culture System to Modulate Tissue Engineered Bone Formation by Varying Loading Conditions.. Proceedings of the 7th International Conference on Manufacturing ResearchProceedings of the 7th International Conference on Manufacturing Research, 443-448.
- . Bone, 44(5), 822-829.
- . Journal of Non-Crystalline Solids, 354(15-16), 1690-1696.
- . Regen Med, 3(2), 145-156.
- . Biomaterials, 28(28), 4091-4097.
- . Tissue Engineering, 13(12), 2881-2890.
- . Journal of Biomechanics, 39, S219-S219.
- . MECHANICS OF ADVANCED MATERIALS AND STRUCTURES, 12(3), 239-246.
- Solution-mediated effect of bioactive glass in poly (lactic-co-glycolic acid)-bioactive glass composites on osteogenesis of marrow stromal cells, 75A(4), 794-801.
- . You have full text access to this content Journal of Biomedical Materials Research Part A, 73A(1), 21-29.
- . Cell Communication and signaling, 3(3).
- . Am J Physiol Cell Physiol, 284(4), C934-C943.
- . Connective Tissue Research, 44(1), 305-311.
- Attachment of human marrow stromal cells to titanium surfaces.. The Journal of oral implantology, 29(2), 66-72.
- Fluid flow induced PGE(2) release by bone cells is reduced by glycocalyx degradation whereas calcium signals are not. BIORHEOLOGY, 40(6), 591-603.
- BMP responsiveness in human mesenchymal stem cells, 44, 305-311.
- Development of preparation methods for and insights obtained from atomic force microscopy of fluid spaces in cortical bone. Scanning, 24(1), 25-33.
- . The Journal of Biological Chemistry, 276(16), 13365-13371.
- . Equine Veterinary Journal, 32(2), 95-100.
- . Journal of Biomechanics, 33(3), 337-343.
- . Journal of Biomechanics, 33(9), 1131-1134.
- The development of microcracking and failure in bone depends on the loading mode to which it is adapted. The Journal of Experimental Biology, 202(5), 543-552.
- . Journal of Orthopaedic Research, 15(1), 111-117.
- . Journal of Orthopaedic Research, 15(6), 862-868.
- . Biomaterials, 16(16), 1267-1271.
- . Biofabrication.
- . Connective Tissue Research, 1-17.
- . International Journal of Molecular Sciences, 25(4), 2085-2085.
- . Current Osteoporosis Reports.
- . Langmuir.
- . Journal of Materials Chemistry B.
- . Biomechanics and Modeling in Mechanobiology.
- . Frontiers in Bioengineering and Biotechnology, 8.
- . Biofabrication, 11(3), 035026-035026.
- . Materials Research, 21(5).
- . Metals, 5(4), 1902-1920.
- . Metals, 4(3), 401-409.
- . Applied Sciences, 11(15), 6994-6994.
Chapters
- , VITAMINS AND HORMONES: STEM CELL REGULATORS (pp. 417-480).
- Preparation and bioacttve characteristics of porous borate glass substrates (pp. 3-10).
- , Bioelectric Engineering (pp. 69-97). Springer US
- , Mechanobiology (pp. 43-60). John Wiley & Sons, Inc.
- , Sustainable Agriculture InTech
Conference proceedings papers
- THE ROLE OF MULTIFUNCTIONAL NANOMATERIALS IN NEW TISSUE REGENERATION STRATEGIES. TISSUE ENGINEERING PART A, Vol. 29(11-12) (pp 828-828)
- MCSS SUPPORT A LAMELLA-LIKE TWISTING ORIENTATION OF COLLAGEN WHEN CULTURED ON ALIGNED ELECTROSPUN POLYCAPROLACTONE FIBRES. TISSUE ENGINEERING PART A, Vol. 29(11-12) (pp 1586-1587)
- ELUCIDATION OF COLLAGEN FIBRE STRUCTURE IN OSTEOGENESIS IMPERFECTA USING SECOND HARMONIC GENERATION IMAGING ON POLYCAPROLACTONE FIBRES. TISSUE ENGINEERING PART A, Vol. 29(11-12) (pp 953-953)
- Effect of HA Particle Size and Quantity on The Bioactive and Biological Behaviour of PU Scaffolds. TISSUE ENGINEERING PART A, Vol. 29(13-14)
- Development of an in vitro musculoskeletal model using poly (glycerol sebacate methacrylate) (PGSM) polyHIPE-based 3D microporous scaffold encompassing regionally controlled mechanical properties. TISSUE ENGINEERING PART A, Vol. 29(13-14)
- CRANIOFACIAL BONE DEFECT REPAIR USING POLYMER SCAFFOLDS AND CELL DERIVED MATRIX. TISSUE ENGINEERING PART A, Vol. 29(11-12) (pp 1118-1119)
- CERIUM, ZIRCONIUM AND COPPER DOPED ZINC OXIDE NANOPARTICLES FOR BONE REGENERATION AND ANGIOGENESIS. TISSUE ENGINEERING PART A, Vol. 29(11-12) (pp 1380-1381)
- Bone Clip: Developing an angiogenic biomaterial to increase bone healing. TISSUE ENGINEERING PART A, Vol. 29(13-14)
- Development of an in vitro musculoskeletal model using poly (glycerol sebacate methacrylate) (PGSM) polyHIPE-based 3D microporous scaffold encompassing regionally controlled mechanical properties. TISSUE ENGINEERING PART A, Vol. 29(13-14)
- Effect of HA Particle Size and Quantity on The Bioactive and Biological Behaviour of PU Scaffolds. TISSUE ENGINEERING PART A, Vol. 29(13-14)
- Bone Clip: Developing an angiogenic biomaterial to increase bone healing. TISSUE ENGINEERING PART A, Vol. 29(13-14)
- VISUALIZATION OF COLLAGEN FIBRE STRUCTURE IN OSTEOGENESIS IMPERFECTA USING SECOND HARMONIC GENERATION IMAGING ON POLYCAPROLACTONE SCAFFOLD. TISSUE ENGINEERING PART A, Vol. 28 (pp S601-S602)
- CRANIOFACIAL BONE DEFECT REPAIR USING POLYMER SCAFFOLDS AND CELL DERIVED MATRIX. TISSUE ENGINEERING PART A, Vol. 28 (pp S551-S552)
- Effect of HA particle size and quantity on the bioactive and biological behaviour of PU scaffolds. TISSUE ENGINEERING PART A, Vol. 28 (pp 480-480)
- Investigating the barrier membrane properties of biphasic PCL scaffolds for guided tissue regeneration. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol. 256
- Assessment of the osteogenic and angiogenetic potential of in vitro generated extracellular matrix decorated multiscale porous polyHIPE scaffolds. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol. 256
- Collagen and Mineral Deposition by MLO-A5 Late-Stage Osteoblasts, is Guided by the Fibre Alignment of Electrospun Scaffolds. Proceedings of the 22nd Congress of the European Society of Biomechanics, 10 July 2016 - 13 July 2016.
- Highly Porous Particles for Cell Recruitment and Delivery in Bone Tissue Engineering. TISSUE ENGINEERING PART A, Vol. 21 (pp S287-S288)
- Using composite scaffolds to engineer bone templates for in-vitro testing. Bone Research Society Conference. 葫芦影业, 11 May 2014.
- A polyurethane-hydroxyapatite composite scaffold as a template for an in-vitro bone model. ICMOBT 2013. Spain, 8 December 2013 - 12 December 2013.
- Using Electrospun Composite Scaffolds as a Template for In-Vitro Bone Matrix Formation. Proc. of the 7th MSC Meeting. Birmingham, 12 September 2013 - 13 September 2013.
- Polyurethane-Hydroxyapatite composite scaffolds for in vitro bone tissue engineering. European Cells and Materials, Vol. 26(7) (pp 38)
- . 6TH ASIA-PACIFIC CONGRESS ON SPORTS TECHNOLOGY (APCST), Vol. 60 (pp 459-466)
- Primary cilia removal inhibits osteoblastic matrix-forming response to mechanical stimuli. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Vol. 6
- Mechanical stimulation of mesenchymal stem cells in a 3D glass scaffold using oscillating and unidirectional flow. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Vol. 6 (pp 344-344)
- Optimizing cell sources for cleft palate repair. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Vol. 6 (pp 4-4)
- Feasibility of 3D printing and stereolithography for fabrication of custom-shaped poly (lactic acid): hydroxyapatite composite biomaterial scaffolds. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Vol. 6 (pp 367-367)
- . Journal of Biomechanics, Vol. 45 (pp S339-S339)
- Diblock copolymer foam surface chemistry influences mesenchymal stem cell fate. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol. 243
- . BONE, Vol. 48 (pp S227-S227)
- Synthesis of interpenetrating polymer networks scaffolds of poly (vinyl pyrrolidone) and poly (acrylic acid). European Cells and Materials, Vol. 22(SUPPL.2) (pp 45)
- Porous metal implants for enhanced bone ingrowth and stability. European Cells and Materials, Vol. 22(SUPPL.3) (pp 1)
- Hyaluronan as a potential mechanotransduction mediator. European Cells and Materials, Vol. 22(SUPPL.2) (pp 6)
- Using a tissue engineering approach for the treatment of cleft palate. European Cells and Materials, Vol. 22(SUPPL.3) (pp 6)
- Response of dermal fibroblasts to dynamic tensile loading. European Cells and Materials, Vol. 22(SUPPL.2) (pp 41)
- 3D cell instructive scaffolds to direct stem cell fate. Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011, Vol. 3 (pp 256-259)
- Nano-domain detection in Poly (vinyl pyrrolidinone) hydrogels. European Cells and Materials, Vol. 18(SUPPL. 2) (pp 33)
- Mechanical responses of bone tissue formation in 3D engineered constructs via primary cilia. European Cells and Materials, Vol. 18(SUPPL. 2) (pp 16)
- Development of a Culture System to Modulate Tissue Engineered Bone Formation by Varying Loading Conditions.. Proceedings of the 7th International Conference on Manufacturing Research, Vol. 7 (pp 443-448)
- Interactions between Obesity, Cardiovascular Disease and Bone Formation.. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 23 (pp S489-S489)
- The Response of Matrix Synthesizing MLO-A5 Cells to Fluid Shear. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 23 (pp S147-S147)
- . Journal of Biomechanics, Vol. 41 (pp S385-S385)
- . Journal of Biomechanics, Vol. 41 (pp S193-S193)
- ATP release from osteoblasts is increased in response to mechanical loading by different amounts when grown in standard monolayer and novel 3D scaffolds. CALCIFIED TISSUE INT, Vol. 83(1) (pp 16-16)
- Effects of frequency and loading duration on mechanically modulated collagen production by osteoblasts in bone tissue engineering. TISSUE ENGINEERING PART A, Vol. 14(5) (pp 844-844)
- Different types of mechanical loading induce differentitial ATP release from osteoblasts grown on 3-dimensional scaffolds. PURINERG SIGNAL, Vol. 4 (pp S164-S165)
- Electrospun polyurethane scaffolds for mechanical stimulation of cells in bone tissue engineering. TISSUE ENGINEERING PART A, Vol. 14(5) (pp 846-846)
- The role of the primary cilia in mediating mechanically induced increases in matrix production during bone tissue engineering. TISSUE ENGINEERING PART A, Vol. 14(5) (pp 788-788)
- Nanofunctionalization of hydrogels using amphiphilic copolymers.. 8th World Biomaterials Congress 2008, Vol. 2 (pp 1062)
- Nanofuntionalized polymeric networks for tissue engineering applications. European Cells and Materials, Vol. 16(SUPPL. 3) (pp 54)
- The role of mechanotransduction in bone tissue engineering. European Cells and Materials, Vol. 16(SUPPL. 3) (pp 84)
- Cyclical compressive loading induces changes in cellular behaviour and ATP release from osteoblasts grown on 3-dimensional scaffolds. CALCIFIED TISSUE INT, Vol. 82 (pp S115-S116)
- The effects of compressive loading on matrix production by osteoblastic cells cultured in polyurethane scaffolds. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 22 (pp S359-S359)
- Collagen and osteopontin upregulation by mechanical loading of bone cells in porous 3D scaffolds. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 22 (pp S268-S268)
- Osteopontin upregulation in a compression bioreactor using two different scaffolds. TISSUE ENGINEERING, Vol. 13(7) (pp 1740-1740)
- Polyurethane scaffolds for long term mechanical loading in musculoskeletal tissue engineering. TISSUE ENGINEERING, Vol. 13(7) (pp 1743-1743)
- Mechanical stimulation of osteoblastic cells in a 3 dimensional polyurethane foam scaffold.. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 21 (pp S373-S373)
- A 3-dimensional, in vitro model to study the effects of compressive loading on osteoblastic cells. European Cells and Materials, Vol. 11(SUPPL.2) (pp 84)
- Cellular mechanotransduction in Bone: Moving towards a molecular mechanism. European Cells and Materials, Vol. 11(SUPPL.2) (pp 8)
- Biodynamic loading in orthopaedic tissue engineering. MCB Molecular and Cellular Biomechanics, Vol. 3(4) (pp 137-138)
- HCN2 ion channels regulate bone development, mass and strength.. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 20(9) (pp S62-S62)
- Solution mediated effect of bioactive glass in poly (lactic-co-glycolic acid)-bioactive glass composites on osteogenesis of marrow stromal cells. BIOCERAMICS 17, Vol. 17 (pp 619-622)
- Osteogenic effect of bioactive glass on bone marrow cells: Biochemical, chemical and morphological study. Transactions - 7th World Biomaterials Congress (pp 200)
- Differential osteogenic effects of 45S bioactive glass on rat and human mesenchymal stem cells.. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 18 (pp S346-S346)
- An overview of oscialltory fluid flow as a potent loading-induced physical signal in bone cells. American Society of Mechanical Engineers, Bioengineering Division (Publication) BED, Vol. 50 (pp 339-340)
- Manipulation of the glycocalyx of an osteocytic and an osteoblastic cell line does not affect the intracellular calcium increase in response to fluid flow.. J BONE MINER RES, Vol. 16 (pp S481-S481)
- Investigation of the morphology of the lacunocanalicular system of cortical bone using atomic force microscopy. Conference on the Mechanical Properties of Cells and Tissues, Vol. 29 (pp 1074-1081)
- Investigation of the signalling pathways involved in the calcium response of bone cells to oscillating fluid flow.. J BONE MINER RES, Vol. 15 (pp S508-S508)
- Investigation of the glycocalyx of cultured bone cells.. J BONE MINER RES, Vol. 15 (pp S376-S376)
- Using atomic force microscopy to image the lacunocanalicular system of cortical bone.. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 14 (pp S553-S553)
- Stress-induced damage in bone: Microcracking and other toughening mechanisms. JOURNAL OF BONE AND MINERAL RESEARCH, Vol. 11(10) (pp P28-P28)
- . USES Conference Proceedings
- Using a novel stretching device to study the effects of mechanical strain on tenocytes in-vitro. 3rd international conference on Mechanics of Biomaterials and Tissues. Clearwater Beach, Florida, USA., 2009.
Datasets
Other
Preprints
- Research group
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- Gifty Tetteh (In vitro bone models for biomaterials testing)
- Wing Kiu Yeung (Surface coatings for orthopaedic implants)
- Tom Patterson (PolyHIPE particles for bone tissue engineering).
- Robert Owen (In vitro bone models for osteoporosis research).
- Zena Wally (Additive manufacturing of porous metals for dental implants).
- Dirar Qassim (Serum free culture of progenitor cells for craniofacial repair).
- Stefania Marcotti (Mechanobiology of the glycocalyx of bone cells).
- Hossein Bahmaee (Microfluidics for co-culture of bone cells).
- Liam Boyle (Mechanobiology of the primary cilia of bone cells).
- Hannah Murray (A* collaboration with Nanyang Technological University, Singapore on angiogenesis of tissue-engineered scaffolds).
- Leonardo Antonini (sandwich PhD student from Federal University of Rio Grande do Sul, Brazil).
- Professional activities and memberships
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- President of the
- Special visiting researcher (PVE): UFRGS, Brazil
- Fellow of the Higher Education Academy
- Alice L Jee Young Investigator Award at the 37th International Sun Valley Workshop on Skeletal Biology
- Editorial boards of: European Cells and Materials, PLoS ONE, Heliyon and Frontiers in Bioengineering
- Panel member for Marie Sk艂odowska-Curie Fellowships H2020 programme, Life sciences
- Member of the American Society of Bone and Mineral Research, Orthopaedic Research Society, Tissue and Cell Engineering Society and Tissue Engineering and Regenerative Medicine International Society
- Women in Engineering
We interviewed Gwen for the Faculty of Engineering's Wall of Women when she was a Senior Lecturer in Bioengineering. Here's Gwen's interview:
The Wall of Women profiles were taken over a 4/5 year time period and are a snapshot of what our engineers were doing at that time.