Lec17_18_Surfaces_Protein_Surface Interactions.pdf

8/22/2019 Lec17_18_Surfaces_Protein_Surface Interactions.pdf

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BiomaterialsLecture

17

Surfaces:InteractionsofProteins

withSurfaces

Unlessotherwisenoted,sourceInformationforthefollowingslides:

1) B.Ratner,A.Hoffman,F.Schoen,andJ.Lemons:BiomaterialsScience,2nd edition(SanDiego:ElsevierAcademicPress.2004).

2) Butt,HJ.;Graf,K.;Kappl PhysicsandChemistryofInterfaces,2nd Edition(WiletVCH:Weinheim 2006).

3) Modifiedfrom:Anne Mayes3.051J/20.340JMaterialsforBiomedical

Application,MIT,

http://ocw.mit.edu,


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ImportanceofProteinSurfaceInteractions

Modulatecelladhesion

Triggerthe

biological

cascade resulting

in

foreign

body

response

Centraltodiagnosticarray/sensordevicedesign&

performance

Initiateotherbioadhesion:e.g.,marinefouling,bacterial

adhesion


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FundamentalsonProteins


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ProteinFunctions


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ProteinFunctions(cont.)


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ProteinFunctions(cont.)


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ProteinStructure

Proteinshavemultiplestructurallevels.


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ProteinStructure


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ProteinStructure

AAsidegroups

havevariable

chemical

character


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ProteinStructure


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SyntheticPolymersvs.Proteins


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ProteinAdsorptiononBiomaterialSurfaces

In

as

short

a

time

as

can

be

measured

after

implantation

in

a

living

system

(


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Background

A) Proteinactivity

variesinadsorbed

vs.solvatedstate

Why???



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Background

B. Entropicforces



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Background

B. Entropicforces


Gaininentropyprobably

isthemaindrivingforce

duringspontaneous

proteinadsorption!!


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Background

C. Adsorbedproteins

initiatephysiological

responsesto

biomaterials



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ModelsforProteinAdsorption:LangmuirModel


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ModelsforProteinAdsorption:Scatchard Plot


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ModelsforProteinAdsorption:Scatchard Plot

SurfaceSensitive

MeasurementsNecessary

1. Ellipsometry

2. SurfacePlasmon

Spectroscopy

3. QuartzCrystal

Microbalance


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Summary:ProteinAdsorption

Proadsorptionfactors

Dehydrationoftheinterface

Increaseoftheproteininteriormobility

Columbicinteractions

VanderWallinteractions

Antiadsorption

factors

Strongwaterbindingtointerface

Proteinrigidity

Surfacemobility

Lownetcharge


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BiomaterialsLecture

18

Surfaces:InteractionsofProteins

with

Surfaces:

Part

2


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ProteinSurfaceInteractions:Part2


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Vroman Effect


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Observations


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IrreversibleAdsorption


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Restructuring


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MultilayerFormation

M t f Ad b d P t i


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MeasurementofAdsorbedProtein1) Techniquesforquantifyingadsorbedamounts

M t f Ad b d P t i


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MeasurementofAdsorbedProtein

Measurement of Adsorbed Protein


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Measurement of Adsorbed Protein


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InSituEllipsometry

2) Techniquesforquantifyingadsorbedamounts


Ellipsometry


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Ellipsometry

Elli


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Ellipsometry


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SurfacePlasmonResonanceSpectroscopy(SPR)


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f l ( )


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20 40

0.0

0.2

0.4

0.6

0.8

1.0

Reflectivity

IncidentAngle/Deg

Simulatedcurveswithincreasingthickness

Gold Film

Glass Slide

He-Ne Laser

632.8nm

0

Detector

Polarizer

Prism

Adsorbed Molecules

Evanescent wave optical technique

sensitive

to

changes

in

thickness

and

optical

propertiesofthinandultrathinfilmsAngstromsensitivity

Nondestructivetosamples

Attenuated totalreflection (ATR) setup ina Kretschmann configuration,opticsare

awayfrom

the

sample

and

subphase

Surfaceplasmon excitationobserved inreflectivityangularscan

Relativelyinsensitivetoenvironmentalchanges temperature,viscosity,etc.

Multiskop


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Surface Plasmon Resonance Spectroscopy (SPR)


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Quartz Crystal Microbalance (QCM)


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QuartzCrystalMicrobalance(QCM)

Time

Frequency

F

BeginningofAdsorption Equilibration

Injection

Sauerbrey Equation

PersonalComputer

FrequencyCounter

OscillatingCircuit

Piezoelectric

Quartzcrystal

Scatchard Equation

Howtomeasurebindingconstants?

qqq

AFmF 22

ooFFKNKcFF bb

Sauerbrey,G.,Z.Phys. 1959, 155,206.Sauerbrey,

G.,

Ann.N.Y.Acad.Sci. 1949, 51,660672.

QCM D (Dissipation)


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QCMD(Dissipation)

Simultaneousmonitoringoffrequency(F)and dissipation(D)atmultipleharmonicsofthequartzresonator

Dissipationrevealsqualitativeinformationabouttheviscoelasticpropertiesoftheadsorbedlayer

Dissipationofaviscoelasticpolymer

layeron

aquartz

resonator

is

heavily

influencebyitsstructure. RigidfilmsshowsmallDvalueswhilesoftorflexiblefilmsshowlargerDvalues

Modelingtheviscoelasticpropertiesusing

aVoight model

can

yield

quantitativeinformation

stored

dissipated

E

ED

2

LargerEdissipated yields

moreviscoelasticresponse

Dissipation

http://www.qsense.com/$2/qcmd.swf


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Mustuseatechniquesensitivetothestructureoftheprotein

CircularDichroism


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Circular Dichroism


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CircularDichroism


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Documents

Lec17_18_Surfaces_Protein_Surface Interactions.pdf