pla peg electrospinning

1
Electrospun Hybrid Scaffolds Composed of PLA/PEG Mixtures for Tissue Engineering and Drug Delivery E. Llorens 1 , R. Ferran 1 , L. Franco 1,2 , A. RodríguezGalán 1 , J. Puiggalí 1,2 , L. J. del Valle 1 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. [email protected] 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 H 2 O 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.

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Page 1: Pla peg electrospinning

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.

[email protected]

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.