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Electrospun Hybrid Scaffolds Composed of PLA/PEG Mixtures for Tissue
Engineering and Drug Delivery
E. Llorens1, R. Ferran1, L. Franco1,2, A. Rodríguez–Galán1, J. Puiggalí1,2, L. J. del Valle1
1 Departament d’Enginyeria Química, 2 Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C, C/ Pasqual i
Vila s/n, Barcelona E-08028, Spain.
INTRODUCTION
SOLUBILITY
ACKNOWLEDGMENTS
The resulting micro/nanofibers of
PLA/PEG were found to be continuous
even at a high PEG content (70 wt-%).
A smother surface was obtained as the
PEG content was increased.
A preferential deposition of PEG in the
outermost part of the fibers was inferred
as also demonstrated by XPS analysis.
Most of PEG could be easily removed
by exposure to water, otherwise when
scaffolds were exposed to ethanol, large
amount of PEG was retained inside the
fibers.
CONCLUSIONS
This research has been supported by grants from MINECO/FEDER
and AGAUR (MAT2012-36205, 2009SGR-1208, respectively)
CHARACTERIZATION
EVALUATION & EFFECT OF TCS
DSC TGA
6m
INITIAL SCAFFOLD
1 m
947
5.3 (nm)
2m
TCS LOADED SCAFFOLD
500 nm
913
2.8 (nm)
6m
AFTER WASHING WITH EtOH
500 nm
700
1.3 (nm)
6m
AFTER WASHING WITH H2O
500 nm
622
0.2 (nm)
Diameter size of electrospun fibers drastically
diminished after immersion in water and
ethanol. This procedure allowed to get scaffolds
with bigger pores that could facilitate cell
growth.
The diameter of
micro/nanofibers did not
significantly change when TCS
was loaded, although the
roughness of the fiber surface
slightly increased.
All TCS loaded scaffolds were found to be unable to support bacterial
adhesion since the relative values always decreased up to
approximately 15%.
Triclosan could effectively be retained in the fibers after removing
PEG as a consequence of its higher affinity to the more hydrophobic
PLA phase.
Proliferation was enhanced in the
scaffolds with an initial higher PEG
content due to the increased porosity
attained after its solubilization. The
formed 3D-structures were more
favorable for a rapid cell colonization.
BACTERIAL ASSAYS
BIOCOMPATIBILITY ASSAYS
TCS RELEASE
FTIR Infrared spectra showed a
clear decrease in the
intensity of typical PEG
signals after immersion of
the samples in water and in
ethanol .
Hybrid scaffolds were obtained by electrospinning PLA/PEG mixtures over a wide range of compositions (i.e. a
PEG content from 10 to 70 wt-%) and both morphologies and physical characteristics evaluated. Most of the PEG
component could be easily removed by exposure to water, although a small fraction was always found to be retained
in the PLA matrix. Scaffolds with different hydrophilicity could consequently be obtained and even a high porosity
could be achieved if PEG was used as a sacrificial polymer. New scaffolds were effectively loaded with Triclosan,
being found significant differences on the antibactericide activity according to the PEG content. Cell adhesion and
proliferation were well supported by PLA/PEG scaffolds and consequently these materials may have a high
potential for biomedical applications as a result of the particular combination of selected polymer properties.
SEM
REFERENCES
XPS & WEIGHT LOSS
PEG signal
PLA/PEG (C1s)
Pre
immersion
PEG
surface
detection
Post
immersion
PLA
surface
detection
- SPASOVA M., STOILOVA O., MANOLOVA N., RASHKOV I. Journal of Bioactive and Compatible Polymers. 2007, Vol. 22, p. 62-76
- WANG B-Y., FU S-Z., NI P-Y., PENG J-R., ZHENG L., LUO F., LIU H., QIAN Z-Y. Journal of Biomedical Materials Research Part A. 2012, Vol. 100A(2), p. 441-449
- NI P., FU S., FAN M., GUO G., SHI S., PENG J., LUO F., QIAN Z. International Journal of Nanomedicine. 2011, Vol. 6, p. 3065-3075
Samples
Composition
PLA/PEG 100
PLA/PEG 90
PLA/PEG 70
PLA/PEG 50
PLA/PEG 40
PLA/PEG 30
PLA/PEG 0
Thermal characterization show well differentiated melting
peaks associated to each homopolymer.
Immersion
in Water
Immersion
in Ethanol
Porosity graphs demonstrated that a small amount of PEG
always remained in the PLA matrix.
XPS spectra of scaffolds with a higher PEG content
revealed that the fiber surface was mainly constituted by
PEG. The spectra changed dramatically when scaffolds
were immersed in water due to the solubilization of PEG.
Combined TCS release experiments in hydrophilic and
hydrophobic media clearly demonstrate that the drug was
preferentially incorporated in the PLA rich phases.
Thermal degradation of PLA/PEG samples showed two degradation steps
which maximum weight losses at a heating rate of 20ºC/min corresponded to
369 and 426 ºC as characteristic for the decomposition of PLA and PEG
homopolymers, respectively. The weight loss associated to each step was
proportional to the content of the corresponding homopolymer in the
mixture.
