Engineering Biopolymeric
Nanostructured Fibers And Films
For Tissue Engineering Applications
Beatriz Quiñones-Colón1
David Castilla2, Jorge
Almodóvar2
University of Puerto Rico
Mayaguez Campus 1Department of Biology
2Department of Chemical
Engineering
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For example, in the case of osseous tissue, common sources of lesions:
The partial or total loss of organ tissue or function has become one of the most
aggravating problems of human health.
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS
Osteonecrosis
Tumors Traumas
Problem:
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Bioinspiration: The Cell’s Microenvironment
MECHANICAL (Stiffness)
Cellular
Processes
Adhesion
Proliferation
Migration
Differentiation
BIOCHEMICAL (Cytokines ie. growth factors)
Extra-cellular
Matrix (ECM)
(Polysaccharides,
Proteins)
Tissue formation
Tissue regeneration
ANISOTROPY (Cues in gradients)
Need for Biomaterials to capture the native ECM
1. Provide Mechanical & Biochemical Cues
2. Fibrous Nature
Artwork from A. Kawska
Courtesy of C Albiges-Rizo
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 3
Our Approach: Polymeric Biomaterials
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Layer-by-Layer
(LbL) Films
Electrospun
Nanofibers
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 4
1) 2)
ELECTROSPINNING
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 5
Electrospun Scaffolds: Towards ECM
Mimetic Systems
Composition
Scale
Diameter
Morphology
Geometry
Orientation
To produce polymeric fibers of single or mixed materials. Uses a difference in potential to draw very fine (typically on the nano or micro scale)
fibers from a liquid (immediate desolvation).
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 6
Versatile technique used to mimic the extracellular matrix of tissues in
its:
Fiber diameter:
• Range = 49 – 140 nm
• Average = 77 nm
Electrospun Collagen Nanofibers
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 7
Controlling Fiber Diameter
Voltage (25 – 45 kV) Flow Rate (0.5 – 3.0 mL/h)
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 8
Collagen fiber diameter can be tuned by:
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
Oriented / Aligned Collagen Fibers
The body contains three
types of muscle tissue: (a)
skeletal muscle, (b)
smooth muscle, and (c)
cardiac muscle. (Same
magnification) Oriented/aligned fibers that mimics the native muscle
tissue. Spun at 5 mL/hr, 47 kV
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 9
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
Glutaraldehyde Crosslinking Preserves
Nanofiber Structure
Crosslinked nanofibers Crosslinked nanofibers after
exposure to water at 37 °C
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 10
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
Tunable Mechanical Properties by
Glutaraldehyde Crosslinking
Immersion
Vapor
Young's Modulus (MPa) UTS (MPa) Elongation at Break (%)
Immersion 4.1 ± 0.5 1.0 ± 0.4 29 ± 15
Vapor 2.7 ± 0.7 0.9 ± 0.2 38 ± 7
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 11
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
Process preserves Collagen’s native
structure
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 12
FTIR reveals a preservation of collagen’s structure after
electrospinning.
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
Collagen Nanofibrous Scaffold Supports
Mammalian Cell Growth
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 13
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
Collagen Nanofibrous Scaffold Supports
Mammalian Cell Growth
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 14
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 301(9), 2016, 1064-1075
15 INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS
In this work, we successfully produced type I collagen nanofibers by
electrospinning, using a non-toxic solvent.
We observed that the solution preparation, electrospinning process, and
crosslinking methods do not affect the secondary structure of
the type I collagen used. Crosslinked membranes were stable in an
aqueous environment at body temperature, which is crucial for implants and
tissue regeneration purposes.
We demonstrated that it is possible to control the diameter of the
nanofibers by varying the voltage and the flow rate.
According to our results, membranes obtained have mechanical
properties in the range of native tissues and support
mammalian cell culture, indicating potential promise in field of the
tissue engineering.
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INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS
LAYER-BY-LAYER
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Polysaccharide-Based Layer-by-Layer Films
Chitosan
Heparin
LbL nano-film preparation on silicon substrate
Simplified molecular representation of LbL film
Takes advantage of the
electrostatic forces of
polymers to generate
multilayers over
biomaterial surfaces.
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS 17
LBL film chemistry and growth
• IR-VASE allows the
evaluation of film
chemistry and
growth.
Incre
asin
g n
um
be
r o
f la
ye
rs
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0
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40
60
80
100
120
140
160
180
3 Bilayers 6 Bilayers 9 Bilayers 12 Bilayers Flu
ore
scen
ce M
easu
rem
ent
Number of Bilayers
Viability of NIH3T3 cell line cultured over chitosan-heparin bilayers
Day 1
Day 3
Proliferation of cells after one and three days of being
seeded onto bilayers.
Cells on six bilayers of CHI-HEP
SEM Images. Cells on Six bilayers
of CHI-HEP.
Proliferation of NIH3T3 Cell Lines with CHI-HEP Bilayers
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS
In conclusion, we can create polysaccharides based thin films by
the layer-by-layer method and we can control cell behavior in
these films.
In this work it was demonstrated that by applying the layer-by-
layer method and electrospinning, it is possible to replicate the
native extracellular matrix of tissues,
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Substrato
Superficies bioactivas
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Acknowledgments
Collaborators
UPRM
Dr. Aldo Acevedo
Dr. Barbara Calcagno
Dr. Madeline Torres
Dr. Paul Sundaram
Integra
Dr. Anibal Quintana
www.uprm.edu/biomaterials
http://www.uprm.edu/biomaterials
http://www.uprm.edu/p/biomaterials/graduate_students
Location Component Pure
collagen %
Nanofibers % Crosslinked
nanofibers %
1613.2 β-turns 16.49 18.61 18.78
1626.4 β-sheets 21.09 26.27 19.68
1637.3 triple helix 18.92 21.01 18.54
1650.6 unordered 31.11 23.28 29.84
1655.0 α-helix 12.40 10.85 13.17
Preservation of Collagen’s Secondary Structure
Pure Nanofibers Crosslinked
Castilla D., Almodovar J. et al, Macromol. Mater. Eng., 2016, 10.1002/mame.201600156
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS
Infrared Variable Angle Spectroscopic
Ellipsometer (IR-VASE)
https://www.google.com.pr/search?q=ir+vase+polarized+light&espv=2&biw=112
3&bih=701&source=lnms&tbm=isch&sa=X&ved=0ahUKEwimyqX7po3MAhVCq
B4KHccNCpMQ_AUIBigB#imgrc=2WdQwbMg_RDGlM%3A
Chemical Composition
Sample thickness
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS
This a non-destructive characterization technique combining the fundamentals of
ellipsometry and FTIR spectroscopy.
Electrospinning of type I Collagen
1. Solvent
90% acetic acid in water
2. Concentration
20% w/v
3. Voltage
47 kV
4. Flow Rate
1 mL/hr
5. Gluteraldehyde
crosslinking
Immersion
Vapor
INTRODUCTION OBJECTIVES METHODOLOGY RESULTS CONCLUSIONS