Upload
tuyen
View
62
Download
2
Tags:
Embed Size (px)
DESCRIPTION
Cell migration at biointerfaces Dr. Prabhas Moghe Biointerfacial Characterization 125:583 September 18, 2006. Outline. Importance of Cell Migration Modes of cell migration Cell migration and cell adhesion Methods to quantify cell migration Cell migration on dynamic biointerfaces. - PowerPoint PPT Presentation
Citation preview
1
Cell migration at biointerfaces
Dr. Prabhas MogheBiointerfacial
Characterization125:583
September 18, 2006
2
Outline• Importance of Cell Migration• Modes of cell migration• Cell migration and cell adhesion• Methods to quantify cell migration• Cell migration on dynamic
biointerfaces
3
Significance of studying cell motility
• Cell motility is key to:– Wound healing/repair (quality and kinetics)– Tissue adhesion and turnover on implanted
materials– Cancer invasiveness/metastasis– Sorting of cells during
development/embryogenesis– White blood and immune cell functions
–
4
Modes of Cell Migration - A Primer
(a)
(c)(d)
(e) (f)
(b)
(a) Random Motility: No orientation bias is exhibited with respect to S or P. (b) Topotaxis: Biased turning toward gradient direction (shown toward right) (c) Orthotaxis: Enhanced S when the cell is oriented in the gradient direction, (d): Klinotaxis: Decreased P when the cell is oriented in the gradient direction (e): Orthokinesis: S decreases with increasing stimulus concentration (f) Klinokinesis: P increases with increasing stimulus concentration
S: Cell SpeedP: Directional Persistence
Simplest Classification: Random Motility versus Chemotaxis
5
Cell MigrationIndirect Methods
• Under-Agarose Assay• Membrane Infiltration Assay (Millipore/Boyden)• 3-D Conjoined Gel Assay• Orientation Assay (Zigmond)
6
Cell Migration AssaysFilter Assay
Under-Agarose Assay
Conjoined Gel Assay
7
Molecular View of Cell Adhesion
8
Strength of Adhesion & Receptor-Ligand Affinity
Kuo SC. Lauffenburger DA. Relationship between receptor/ligand binding affinity and adhesion strength. [Journal Article] Biophysical Journal. 65(5):2191-200, 1993 Nov.
9
Relation between cell adhesion and cell migration
DiMilla et al., JCB, 1992
10
Cell migration & cell adhesive strengthPalecek et al., Nature 385:537 (1997)
11
3-D Cell migration
Biophys J. 2005 Aug;89(2):1389-97. Epub 2005 May 20.
12
Cell Migration Analysis on Biomaterials: Direct
Methods
Biophys J. 1997 Mar;72(3):1472-80. Biophys J. 1992 Feb;61(2):306-15.
13
Direct Migration Methods, Contd.
D2(t)=4μ{t−P+Pexp(−t/P)}
14
Theory of Cell Migration:Indirect Assays
• Cell Population Migration is described in terms of objectivemigratory parameters, , and . These parameters do not vary withsystem size, time of incubation, etc.
= random motility coefficient (cm2/s) = chemotaxis coefficient (cm2/s-M)
• Two fundamental equations are required:- Cell transport equation (captures migration behavior)- Cell conservation equation
15
Theory of Cell Migration• Cell Migration in an Isotropic Environment (Random Migration):
Jc =−μ(a).∂C∂xwhere c is the cell density and a is the concentration of soluble stimulant concentration (if any).
• Cell conservation equation:∂C∂t =−∂Jc∂x
• ∂C∂t =μ.∂
2C∂x2Overall equation:
16
Solution to Cell Migration Model
time, t
Co
xSolution: If η =x/ 4μ.t
C(η) =Co.{1−erf(η)}
C(x,t)
C(η)
ηerf(η) = 2π
e−y2dy
0
η∫where
(Note, erf(0)=0; erf(∞)=1)
17
Example of variation with biomaterial substrate
10
-9
10
-8
10
-7
0 10
-10
10
-9
10
-8
10
-7
Untreated ePTFE
Albumin-ePTFE
IgG-ePTFE
Random Motility Coefficient
[
2
/s]
FMLP Conentration [ M ]
Chang, C., Lieberman, S., and Moghe, P.V., J. Mat. Sci. Mat. Med. 11: 337 (2000)
• Human Neutrophilson ePTFE, a vascularprosthetic material,treated with differentplasma proteins, andin the presence ofthe chemoattractant,formyl-methionyl-leucyl-phenylalanine (fMLP).
18
Protein interface on biomaterials shifts the directional motility of cells
Chang, C., Lieberman, S., and Moghe, P.V., J. Mat. Sci. Mat. Med. 11: 337 (2000)
19
Cell migration on anisotropic substrates
• Cell migration under flow• Cell migration on oriented textured
substrates• Cell migration on substrates with
chemical, electrical, stiffness gradients.
20
Analysis of Cell Motility on Biosubstrates under Flow
Rosenson-Schloss et al,J. Biomed. Mater. Res., 60:8, 2002’
21
22
23
Quantitation of Cell Migration under Flow
24
Cell migration on dynamic biointerfaces (ligand-nanoparticles)
Tjia and Moghe, Tissue Eng, 8: 247 (2002); Annals of Biomed. Eng, 30: 851 (2002)
25
Cell motility behavior characterization as a function of ligand-microparticle density
(Tjia and Moghe, Tissue Eng., 2002)
26
Cell motility behavior characterization, continued
27
Mathematical description of cell motility and ligand binding (Tjia & Moghe, ABE, 2002)
28
Kinetics of ligand binding and internalization within motile cells
29
Cell motility correlates with matrix ligand sampling