Acheson, Jonathan

Dunne, Nicholas

Goel, Saurav

Hamilton, Andrew

Lennon, Alex

Ziminska, Monika

English

Queen's University Belfast Research Portal

Mechanical and Physical Response of Nanocomposite-Coated Foams Subjected To Hydration: Potential Uses For Bone Tissue Scaffolds

Ulster University's Research Portal

Mechanical and Physical Response of Nanocomposite-Coated Foams Subjected To Hydration: Potential Uses For Bone Tissue ScaffoldsAcheson, J1. Goel, S1. Dunne, N2, 3, 4. Hamilton, A11School of Mechanical and Aerospace Engineering, Queen’s University Belfast, UK2Medical Engineering Research Centre, School of Mechanical and Manufacturing Engineering, Dublin City University, Ireland3School of Pharmacy, Queen’s University Belfast, UK4Trinity Centre for Bioengineering, Trinity College Dublin, IrelandLayer by Layer AssemblyINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORKDrug ReleasingSurface Interaction 1. Mertz D et al. Nano Lett. 2007;7(3):657–62. Controlled DegradationMechanical PropertiesMechanical Properties of Coating on 3D SubstratesZiminska et al. ACS Appl Mater Interfaces. 2016;8(34):21968–73.INTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORKTo use coatings in bone tissue scaffold applications; mechanical and physical response of the coating upon submersion into a aqueous environment need to be investigatedMechanism OverviewPositively Charged PolymerDIWaterNegatively harged  Negatively Charged Species Positively Charged SpeciesNegatively Charged Surface- - - - - - - - - - - - - - - - - - - - - - - -1QuadlayerINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK• Open cell polyurethane foam (12.7Ø x 10 mm)[1]• Glass microscope slides (2 x 1 cm)• Coated with: » 15 quadlayers» 30 quadlayers» 45 quadlayers» 60 quadlayers• Samples tested in:» Air (∼25% RH, Ambient Temp)[1]» Submerged de ionised water (100% RH, Ambient Temp)» Humidity chamber (∼50 to ∼85% RH, Ambient Temp)Materials0.5cmUncoatedCoatedPolyurethane foamMasked Sample1. Ziminska et al. ACS Appl Mater Interfaces. 2016;8(34):21968–73.INTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORKElastic Modulus of Coated Foams6% deformation at crosshead speed of 2 mm/min010203040506070809001234560 15 30 45 60Mass (mg)Elastic Modulus (MPa)Number of Deposited QuadlayersElastic Modulus (MPa) Mass (mg)100Uniaxial Compression0.0856gGravimetric AnalysisINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK(n=5)Ambient012345678915 Quadlayers 30 Quadlayers 45 Quadlayers 60 QuadlayersThickness (µm)Thickness Measurements of Coating on Glass Slides(n=100)Masked SampleSurface ProfilometryCoatingMasked SampleINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORKSurface profilometry using Tencor alpha step 200AmbientMechanical Properties of Coated Foams Under Aqueous ConditionsWhen tested upon immediate submersion in DI water, elastic modulus drops significantlyAverage Elastic Modulus (MPa) ± SDQuadlayers Ambient Hydrated Hydrated 1 Hour Desiccated0 0.08 ± 0.00 0.05 ± 0.00 0.05 ± 0.01 0.10 ± 0.0115 1.31 ± 0.21 0.06 ± 0.01 0.06 ± 0.01 1.08 ± 0.2730 2.78 ± 0.26 0.08 ± 0.01 0.08 ± 0.01 2.54 ± 0.3545 3.19 ± 0.28 0.07 ± 0.01 0.07 ± 0.00 3.52 ± 0.3760 4.9 ± 0.46 0.10 ± 0.01 0.09 ± 0.01 5.17 ± 0.60(n=5)01234560 15 30 45 60Elastic Modulus (MPa)Number of Deposited QuadlayersDI Water Bath00.020.040.060.080.10.120 15 30 45 0Elastic Modulus (MPa)Number of  uadlayersAmbient012345615 30 45 60Elastic Modulus (MPa)Number of Deposited QuadlayersINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORKHydrated02468101215 Multilayers 15 Multilayers Hydrated 30 Multilayers 30 Multilayers Hydrated 45 Multilayers 45 Multilayers Hydrated 60 Multilayers 60 Multilayers HydratedThickness (µm)** ** ** **Thickness Measurements of Coating on Glass Slides when Hydrated15 Quadlayers 30 Quadlayers 45 Quadlayers 60 QuadlayersAmbient Hydrated**Statistically significant increase (p < 0.01) in coating thickness when hydrated INTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK(n=100)HydratedMechanical and Gravimetric Analysis of Coated Foam in Humidity ChamberINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORKR² = 0.967490951001051101151201251300123456Ambient (∼25)51 55 58.5 62 65 71 78 82 Submerged(100)Mass (mg)Elastic Modulus (MPa)Relative Humidity (%)(n=1)Water Acting as a PlasticiserINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK[1] OT et al. Langmuir. 2006;22(11):5137–43. Proposed Solution:Water Distribution in Multilayers of Weak Polyelectrolytes[1]Crosslinking ResultsHydrated TestingINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK00.050.10.150.20.250.30.350.40.45 None 120°C 180°C 0.125M GA 1.25M GAElastic Modulus (MPa)Crosslinking MethodPreliminary crosslinking results on 15 quadlayer coated foams Elastic modulus of coated foam is reduced to that of an uncoated level Coating thickness when hydrated is significantly increased Elastic modulus of coated foam recover post desiccation Increasing mass in conjunction with lowering elastic modulus under increasing relative humidity Effects of hydration on coating synonymous with water plasticisation as described by Tanchak et al.[1] Crosslinking of coating improves hydrated elastic modulus significantly» Thermal crosslinking offering slight improvement in elastic modulus» Chemical crosslinking offering significant improvement in elastic modulusConclusionsINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK[1] OT et al. Langmuir. 2006;22(11):5137–43. Future workINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK Design of experiments to optimise mechanical properties of coating when hydrated Chemical crosslinking Thermal crosslinking Water vapour “barrier” layersFuture workINTRODUCTIONMATERIALS AND METHODSRESULTS CONCLUSIONS FUTURE WORK Incorporating degradable barrier layers into system3D SubstrateAverage Elastic Modulus (MPa) ± SDQuadlayers Ambient Hydrated0 0.08 ± 0.00 0.05 ± 0.0015 1.31 ± 0.21 0.06 ± 0.0130 2.78 ± 0.26 0.08 ± 0.0145 3.19 ± 0.28 0.07 ± 0.0160 4.9 ± 0.46 0.10 ± 0.013D SubstrateMechanical PropertiesTime[Image] MD et al. Nano Lett. 2007;7(3):657–62. AcknowledgementsSpecial ThanksDr. A HamiltonM. ZiminskaDr. N DunneDr. S GoelBioengineering Research GroupDEL Funding 

Mechanical and physical response of nanocomposite-coated foams subjected to hydration: potential uses for bone tissue scaffolds

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Mechanical and physical response of nanocomposite-coated foams subjected to hydration: potential uses for bone tissue scaffolds

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