Highly Aligned Nanocomposite Scaffolds by Electrospinning and Electrospraying
for Nerve Regeneration
1
Zhu
1,2
Zhang
Wei
and Lijie Grace
1Department of Mechanical and Aerospace Engineering and 2Department of Medicine, The George Washington University
INTRODUCTION
Self-regeneration capacity of nerve system in human species is
extremely limited. As a result, most of patients with nerve damages
are suffering from the loss of sensory or motor functions. Plenty of
efforts have been put on recovering nerve tissue function. Scaffoldbased neural tissue engineering technologies provide great
opportunity for guiding nerve regeneration. In this study, we
developed a novel tissue engineered scaffold which possesses highly
aligned poly caprolactone (PCL) microfibrous framework and bovine
serum albumin (BSA) embedded poly (D, L-lactide-co-glycolide)
(PLGA)
nanospheres
fabricated
by
electrospinning
and
electrospraying techniques. The highly aligned microfibers play an
important role in guiding axon propagation. Meanwhile, the
introduction of PLGA nanospheres can alter the PCL scaffold’s
surface properties (such as increased nano surface roughness and
wettability) and promote neural cell adhesion and proliferation. More
importantly, neurotropic factors could be easily loaded inside the
PLGA nanospheres and be sustainably released to enhance neural
tissue regeneration in a long term.
RESULTS
RESULTS
(A)
(B)
Figure 5. Raman spectra of pure PCL and PLGA nanospheres coated scaffolds.
(a)
(b)
MATERIALS AND METHODS
Highly aligned and random neural nanocomposite scaffolds were
prepared via an electrospinning technique (Figure 1) and followed by
electrospraying method. PCL served as a biocompatible bulk scaffold
material. Novel core-shell PLGA nanospheres with BSA aqueous
solution inside were produced by co-axial electrospraying process
and sprayed onto PCL fibers (Figure 2). Rat pheochromocytoma
(PC-12) cells were used as a model neural cell to evaluate the
scaffolds’ cytocompatibility property. PC12 cell adhesion and
proliferation were evaluated on the core-shell scaffolds in vitro.
Figure 3. SEM images of electrospun microfiberous scaffolds : (A) random PCL scaffold and (B) highly aligned
PCL scaffold. Analysis of orientation with OrientationJ plug-in for imageJ (a) random and (b) aligned electrospun
fibers.
(A)
Figure 6. PC-12 cell proliferation after 2, 4 and 6 days. Data are ±SEM, n=6; *p<0.05
when compared to all other scaffolds after 4 and 6 day proliferation.
(B)
(B)
(A)
(A)
(B)
Fiber
orientation
(C)
(D)
180
Contact Angle (Degree)
Figure 1. Schematic illustration of our electrospinning set-up for (A) aligned and
(B) random microfiber fabrication .
160
140
*
120
Figure 7. Confocal microscopy images of PC-12 cell spreading morphology. (A) axons
extension along highly aligned fibers and (B) undirectional growth on random
scaffolds. PC-12 cells were cultured in media with 50 ng/ml NGF for one week.
CONCLUSIONS
100
80
Our study demonstrated the potential of a novel highly aligned PCL scaffolds with
core-shell PLGA nanospheres for nerve tissue engineering. The scaffolds can provide
biomimetic and cell favorable microenvironment for the growth of PC-12 cells, thus
worth further exploration towards nerve regeneration.
60
40
20
0
PCL
Figure 2. Schematic diagram of the electrospraying technique for producing
PLGA nanospheres into PCL eletrospun scaffolds.
PCL with PLGA nanospheres
Figure 4. SEM images of highly aligned nanocomposite scaffolds: (A) pure PCL, (B) PCL scaffold with coreshell PLGA nanospheres at low magnification and (C) at high magnification. (D) Contact angles comparison of
scaffolds with and without PLGA nanospheres. Data are mean ±SEM, n=5; *p<0.05 when compared to controls
ACKNOWLEDGEMENTS
The authors would like to thank the financial support from GW Institute for
Nanotechnology for this project.