Polymeric and metallic cardiovascular biomaterials: phospholipid and silicone surface modification by gamma radiation surface graft polymerization and electropolymerization

176 Pages·2000·10.9 MB·English

by  Jenkins, Lauri Laurene

POLYMERICANDMETALLICCARDIOVASCULARBIOMATERIALS:
PHOSPHOLIPIDANDSILICONESURFACEMODIFICATIONBYGAMMA
RADIATIONSURFACEGRAFTPOLYMERIZATIONAND
ELECTROPOLYMERIZATION
By
LAURIL JENKINS
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOLOFTHE
UNIVERSITYOFFLORIDAINPARTIALFULLFILLMENTOFTHE
REQUIREMENTSFORTHEDEGREEOFDOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2000
Copyright2000
by
LauriL.Jenkins
Thisdissertationisdedicatedtomyparents,RuthandDonLaurene,andmysisterKay
Laurene.ThethreepeopleinmyHfethatlovesmeunconditionally.
ACKNOWLEDGMENTS
IwouldfirstliketothankDr.E.P.Goldbergforhisguidanceandpatienceandto
theallthemembersoftheGoldbergResearchGroupfortheirsupportand
encouragement.ThishasbeenthemosthelpfulresearchgroupthatIhaveeverworked
withandIwillsincerelymissallofthem.
SpecialthanksgoestoDr.DrewAmeryforconstantlyfixingtheXPSandalways
beingtheretobemy"computerandelectronics"guy.Theelectrochemistryprojectwasa
continuanceofDrew'soralproposalandwithouthistechnicalexpertise,wouldhave
takenmonthslongertoinitiate.
Dr.ChrisWidenhousealsowasalsoinvolvedintheconceptionofthe
electropolymerizationprojectwithhisfirstfewexperimentswiththeMAOPoligomer.
KaustubhRauwasalwaysthereandreadytohelpmegivemeadvice.Krauhas
notonlybeenagoodresearchmatebutagoodfriend.
ThanksgotoDanUrbaniakforhisworkduringthemitialelectrochemistry
feasibilitystudy.ThankstoPaulMartinforcoatingmySEMstubs.
IamindebtedtoProfKazuhikoIshihara,ProfNobuoNakabayashi,andProf.
YasuhikoIwasakiwhonotonlyprovidedthegroundworkforthephospholipidresearch,
butalsowereverygenerousinthesupplyoftheMPCmonomerformyresearch.My
sinceregratitudeisextendedtothemfortheirkindnessandgenerosity.
iv
IwouldalsoliketothankDr.Ambroseforlendingmethepotentiostatandchart
recorderusedintheelectropolymerizationstudiesandforhisinsightintothe
electrochemistryofmetalsurfaces.
Thankstomycommitteemembersfortheirguidanceandtimethattheyhave
givenmeoverthelastfewyears.
V
TABLEOFCONTENTS
gage
ACKNOWLEDGMENTS
LISTOFTABLES
LISTOFFIGURES xi
ABSTRACT xviii
CHAPTERS
1 INTRODUCTION 1
2 BACKGROUND 6
ScientificGoals 6
SurfaceModifications 6
Phospholipids 6
Silicones 15
GammaRadiationSurfaceGraftPolymerization 17
Electropolymerization 18
Applications 22
SyntheticVascularGrafts 22
EndoluminalCardiovascularStents 25
3 MATERIALSANDMETHODS 36
GammaRadiationSurfaceModificationofSilicone 36
Materials&Reagents 36
SurfaceModificationExperiments 37
GammaInitiatedMPC/HEMAandMPC/MAACopolymerModification
ofPDMS 39
GammaMPCModificationofPDMS 41
Two-StageGammaRadiationModificationofPDMS 42
GammaMPCModificationofPDMS 44
GammaMPC/MMACopolymerModificationofPDMS 45
SurfaceModificationbyElectropolymerization 45
vi
Substrates&Reagents ^-^
ElectropolymerizationEquipment&CellDesign 47
FeasibilityStudy 47
ElectrochemicalExperimentalDesign&Surface
ModificationExperiments 49
ExperimentalDesigns 50
Methacryoloxy-Terminated-Polydimethylsiloxane(MAOP)
Oligomer 50
Vinylmethoxysiloxane(VMS)Oligomer 50
Methacroylphosphorylcholine(MPC)Monomer 51
CopolymerizationStudies 52
VMS-MPCCopolymer 52
MAOP-MPCCopolymer 53
ElectropolymerizationControlExperiments 53
ElectropolymerizationCharacterizationTechniques 54
ContactAngle 54
X-RayPhotoelectricSpectroscopy 55
ScanningElectronMicroscopy 56
FourierTransformInfraredSpectroscopy 56
4 RESULTSANDDISCUSSION 59
GammaRadiationSurfaceGraftModificationofSilicone 59
MPC/HEMAandMPC/MAACopolymerModificationofPDMS 59
GammaMPCModificationofPDMS 62
Two-StageGammaGraftModificationofPDMS 65
MPC/MMACopolymerModificationofPDMS 68
DiscussionofGammaPolymerizationofHydrogelMonomerson
PDMS 68
ElectropolymerizationofMPCandSiliconeOligomersonStamlessSteel 70
ElectropolymerizationofMethacryoloxy-Terminated-
Polydimethylsiloxane(MAOP)Oligomer 70
ElectropolymerizationofVinylmethoxysiloxane(VMS)OUgomer 79
ElectropolymerizationofVMSonElectrodesCoatedwith
CouplingAgent 87
ElectropolymerizationofMethacroylphosphorylcholine
(MPC)Monomer 94
ElectrochemicalCopolymerizationofSiliconeOligomerswith MPC..105
VMS-MPCCopolymer 105
MAOP-MPCCopolymer 112
Electrolyte/solventControlExperiments 121
MonomerAdsorptionStudyExperiments 121
Electrolyte/SolventControlExperimentswithno
MonomerPresent 126
DiscussionofElectropolymerizationResults 138
5 SUMMARYANDCONCLUSIONS 143
vii
SUGGESTEDFUTURERESEARCH
GammaRadiationGraftSurfacePolymerizationModificationofPDMS
Electropolymerization
LISTOFREFERENCES ^^'^
BIOGRAPHICALSKETCH
viii
LISTOFTABLES
Table Page
2.LThepercentageoffunctionalgroupsonSRcontrolsandMPCmodifiedSRsurface
asdeterminedbydeconvolutedhighresolutionClsESCAspectra 15
2.2.Summaryofmajorstentmanufacturersandstentdesignsasof1998 32
2.3.Materialsstudiedforuseasstentsurfacemodification 35
3.1.ListingofsamplesforthefirstHEMA/MPCandMAA/MPCco-polymerstudy 40
3.2.ListingofsamplesforthesecondHEMA/MPCandMAA/MPCco-polymerstudy 41
3.3.ConditionsforMPCsurfacemodificationofPDMSbygammainitiation 42
3.4.ConditionsforfirststagemodificationsofPDMSbygammainitiation 43
3.5.SamplesforthestagetwoMPCmodificationsofPDMSbygammainitiation 44
3.6.MPCmodificationofPDMS/DMSO 45
3.7Preliminaryexperimentsforthepolymericelectrochemicalsurfacemodificationof
stainlesssteel 48
3.8.MAOPexperimentaldesign 50
3.9.VMSExperimentalDesign 50
3.10.Couplingagentcoatedelectrodes&VMS,experimentaldesign 51
3.11.MPCexperimentaldesign 51
3.12.CopolymerizationcoatingexperimentswithMPCandVMS 52
3.13CopolymerizationcoatingexperimentswithMPCandMAOP 53
3.14.Absorptionstudyexperiments 53
3.15.Electrolyte/solventcontrolexperiments 54
ix
4.1.ListingofsamplesandcontactangleresultsforthefirstHEMA/MPCand
MAA/MPCcopolymerstudy 60
4.2.SamplesandcontactangleresultsforthesecondHEMA/MPCandMAA/MPC
copolymerstudy 61
4.3.ConditionsandcontactangleresultsforMPCsiufacemodificationofPDMSby
gammaradiationsurfacegraftpolymerization 63
4.4MPCmodificationofPDMSinDMSO 65
4.5.SamplesandcontactangleresultsforfirststagemodificationsofPDMSbyGRIP 66
4.6.SamplesandcontactangleresultsforthestagetwoMPCmodificationsofPDMSby
gammaradiationsurfacegraftpolymerization 67
4.7.SamplesandcontactangleresultsforMPC/MMAcoppolymermodificationof
PDMS 68
4.8.MAOPExperimentalDesign/Results 72
4.9.VMSExperimentalDesign/Results: 81
4.10.XPSresultsforVMSonstainlesssteel 81
4.11.Couplingagentcoatedelectrodes&VMS,experimentaldesignandresults: 89
4.12.MPCExperimentalDesign/Results: 96
4.13:ResultsofVMS-MPCcopolymerexperiments 107
4.14.CopolymerizationcoatingexperimentswithMPCandMAOP 113
4.15.Absorptionstudyexperiments 122
4.17.Electrolyte/solventcontrolexperiments 128
4.18.XPSresultsfortheelectrolyte/solventcontrolexperiments 128
X