Electrospinning of Polymeric
Nanofibers for Tissue Engineering
Applications
Presented by:
Name (ID)
School of Biochemical Engineering and Technology (BCET)
Introduction
5- 30 kV
Figure 1: Basic Electrospinning Setup
Source: http://www.people.vcu.edu/~glbowlin/images/electrospinning.jpg
2
Parameters for Electrospinning
Table 1: Effect of parameters on morphology of nanofibers
Solution
properties
Control variables Ambient
parameters
• Viscosity/concentration
• Flow rate
• Conductivity/solution
charge density
• Field strength/ voltage • Humidity
• Surface tension
• Polymer molecular
weight
• Dipole moment and
dielectric constant
• Temperature
• Distance between tip
and collector
• Needle tip design
• Collector
composition and
geometry
3
Application in Tissue Engineering
Temporary
Extracellular
Matrix (ECM)
Figure 2: Principle of Tissue Engineering
Source: http://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Tissue_engineering_english.jpg/800pxTissue_engineering_english.jpg
4
Why Nanofiber Scaffolds are required?
Extracellular Matrix (ECM) is composed of two main types of
macromolecules
1. Ground substances (proteoglycans)
Nanoscale
2. Fibrous proteins (collagens)
component
Epithelial cell
Basement membrane
Endothelium
Connective tissue
Fibroblast
Figure 3: Extracellular Matrix (ECM)
Source: http://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Extracellular_Matrix.png/800pxExtracellular_Matrix.png
5
General Properties of Scaffolds

Biocompatible
Ability to integrate with the host tissue

Porous with a high surface-volume ratio
Cell attachment, in-growth and exchange of
nutrients
Angiogenesis upon implantation

Biodegradable
Rate of degradation should be controllable to
mimic the rate of neo-tissue formation
6
Types of Electrospun Scaffolds for
Tissue Engineering Applications

Synthetic polymer scaffolds
 Electrospun poly (D,L-lactide-co-glycolide)
(PLGA)  Most commonly used biodegradable
polymer in tissue engineering
Natural polymer scaffolds
 Composite scaffolds
 Functionalized scaffolds
 Drug delivery carriers

7
Preparation of Electrospun
Nanofiber (PLGA)

Preparing Poly (D,L-lactide-co-glycolide)
(PLGA) solution
1 g of copolymer
PLGA
THF : DMF = 1:1
Tetrahydrofuran (THF)
Dimethylformamide (DMF)
20 mL of organic
solvent mixture
8
Process of Electrospinning
Copper
collecting plate
Glass Syringe
containing
polymer solution
Syringe
- Fit with 18-G needle
- Fix at 45o downtitled from horizontal
Power Supply (18 kV)
Nanofiber
jet
Power
supply
Distance of 20 cm
between the plate and
the needle tip
Figure 4: Scheme of electrospinning apparatus
9
Objectives
To explore the applications of the PLGA
structure in tissue engineering
 To characterize properties of the
structure (i.e. porosity and mechanical
properties)
 To investigate the cell activities within
nano-scale fiber-based scaffold

◦ Use two cell types: fibroblasts and bonemarrow-derived stem cells (MSCs)
10
Physical Property Characterization

Porosity
◦ Pore diameter distribution
◦ Total pore volume and area
◦ Porosity of the structure

Tensile property
◦ Tensile modulus
◦ Ultimate tensile stress
◦ Ultimate tensile strain

Scanning Electron Microscopy (SEM)
◦ Morphology before and after cell seeding
11
Results
Table 2: Porosimetry of the electrospun PLGA structure
Porosity
Total pore volume
Total pore area
91.63 %
9.69 mL/g
23.54 m2/g
Table 3: Tensile Properties of electrospun PLGA structure
PLGA
Cartilage
Skin
Tensile modulus (MPa)
323
130
15-150
Ultimate tensile stress
(MPa)
23
19
5-30
Ultimate tensile strain
(%)
96
20-120
35-115
12
Results (Cont’)
Morphology of electrospun PLGA structure
(a)
(b)
Figure 5: SEM morphographs of the electrospun PLGA (original
magnification x 1500) (a) before cell seeding ; (b) after 3 days of
cell culture. Bar = 10 µm
13
Discussion
High porosity provides more structural
space for cell accommodation and
efficient nutrient exchange and metabolic
waste between scaffold and environment.
 Effective mechanical properties

◦ Retain structural integrity and stability
◦ Provide sufficient biomechanical support
during tissue generation and structure
degradation
14
Conclusion
Electrospun PLGA scaffold is suitable for
tissue substitute.
 High porosity (i.e. surface area-to-volume
ratio) is favorable for cell attachment,
growth and proliferation.
 The structures provide effective
mechanical properties suitable for soft
tissue, such as skin and cartilage.
 A basis for future optimization of
electrospun nanofibrous scaffold

15
References




Quynh P. Pham, Upma Sharma Ph.D., and Antonios
G. Mikos, Ph.D. Electrospinning of Polymeric
Nanofibers for Tissue Engineering Applications: A
Review. Mary Ann Liebert, Inc. 12, 1197, 2006.
Li, W.J., Laurencin, C.T., Caterson, E.J., Tuan, R.S.,
and Ko, F.K. Electrospun nanofibrous structure: a
novel scaffold for tissue engineering. J. Biomed.
Mater. Res. 60, 613, 2002.
Ma, Peter X. (May 2004). "Scaffolds for tissue
fabrication". Materials Today: 30–40.
http://www.people.vcu.edu/~glbowlin/research.ht
ml
16
17