(67d) Nanostructured 3D PLGA Scaffolds For Skin-Tissue Engineering Applications

NANOSTRUCTURED
3D PLGA SCAFFOLDS FOR SKIN-TISSUE ENGINEERING APPLICATIONS

Z. Karahaliloğlu¹, B. Ercan²,
E.B. Denkbaş³, T. Webster²

 ¹Hacettepe University, Nanotechnology and Nanomedicine
Division, 06800, Beytepe, ANKARA, Turkey

²Northeastern
University, Chemical Engineering Department, 02115, Boston, MA, USA

³Hacettepe
University, Chemistry Department, Biochemistry Division, 06800, Beytepe,
ANKARA, Turkey

Background and aims: Skin is the largest organ in the body and performs
various functions (i.e., maintaining temperature, waste exchange, etc.)
critical for our survival. When skin-tissue is damaged due to a burn or a
trauma, natural skin grafts in the form of a xenograft, allograft or autograft have
been providing optimal results for wound healing applications. However, the use
of graft tissue comes with numerous challenges including limited donor site for severe skin trauma patients,
potential for immune response for allographs and xenographs, requirement of a
surgical procedure, and high cost^1,2. Although some of the
commercially available synthetic skin substitutes regenerate some of the
functions of damaged epidermal tissue, there
is no currently-used material that can replace the functional complexity of
natural skin. To address this challenge, we are proposing the use of
nanofeatured poly(lactic-co-glycolic acid)
(PLGA) as an alternative skin substitute. PLGA is an FDA approved biodegradable
and a biocompatible copolymer used in various medical applications such as
resorbable sutures, surgical clips and drug delivery systems³.
Furthermore, there is plenty of in vitro and vivo study showing that nanostructured
PLGA enhances cellular adhesion, proliferation and long-term functions^4,5.
In this research study, nanostructured 3D PLGA scaffolds were created and
investigated as an alternative material for skin-tissue engineering and its
regenerative performance was compared to a nanosmooth PLGA scaffold in vitro.

Methods:
In this work, PLGA scaffolds were prepared by solvent casting and salt leaching
process as reported previously⁴. Briefly, 0.5 g of PLGA (PLGA; 50:50
wt%; Polysciences, Inc.) were dissolved in 6 ml of chloroform in 45 °C for 30
min. 4.5 g of sodium chloride salt (NaCl, up to 250 µm, Sigma) were used to
introduce pores into the substrate. NaCl particles were added to the dissolved
polymer solution. After mixing and sonicating for 20 min, the mixture was
poured into a Teflon petri dish and dried overnight at room temperature. To
evaporate of all chloroform, the dried polymer was placed into a vacuum for 48
h. The scaffold was soaked in deionized water for 3 days. To understand the
effect of PLGA nanorough surfaces on human epidermal keratinocyte (İnvitrogen
C0015C) and fibroblast cell lines (ATCC CCL-110), PLGA scaffolds were soaked in
a NaOH solution prepared at different concentrations (0.1, 0.5 and 1 N) and for
various times (5, 10, 15 and 20 minutes). Characterization of the treated- and
untreated PLGA scaffolds was performed by using Scanning Electron Microscopy
(SEM). Cell adhesion to the scaffold and cell
proliferation was assessed using human fibroblast and human keratinocyte cell
lines. Experiments were completed in triplicate and repeated at least three
times.

Results: SEM images of untreated and treated PLGA scaffolds
exhibited a significant change in surface roughness. Treated PLGA had nano
topographical surface properties while untreated PLGA scaffolds showed a smooth
surface.  Our preliminary results
(not shown here) indicate that nanofeatured PLGA surfaces promoted more skin
cell adhesion compared to its nanosmooth counterpart.

Conclusion: This study
confirmed that PLGA scaffolds altered to have a nanorough surface topography by
chemical etching technique should be further studied for improved skin-tissue engineering
applications.

Figure 1. SEM imagesof(a) untreated and (b) 0.1 N NaOH-treated for 10 min,
(c) 0.5 N NaOH-treated for 10 min, (d) 1 N NaOH-treated for 5 min, (e) 1 N
NaOH-treated for 10 min, (f) 1 N NaOH-treated for 15 min and (g) 1 N
NaOH-treated for 20 min PLGA scaffolds. Scale bars= 200 nm. 

Acknowledgements: The authors would like to thank Daniel Hickey and
Linlin Sun for their assistance. The authors would also like to thank Northeastern
University and Hacettepe University for funding.

References

1.     
Sheila, M. Nature, 2007, 445,
874¨C880.

2.      Marler, J. J.; Upton, J.; Langer, R.; Vacanti, J. P. Advance Drug Delivery Rev. 1998, 33, 165-182.

3.      Kumbar, S.G.; Nukavarapu, S.P.; James, R;, Nair, L.S.;
Laurencin, C.T. Biomaterials, 2008, 29, 4100¨C4107.

4.     
Smith, L.L.;  Niziolek, P.J.; Haberstroh, K.M.; Nauman, E.A.; Webster, T.J. Int J Nanomedicine, 2007, 2(3),
383¨C388.

5.     
Park, G.E.; Pattison, M.A.; Park, K.; Webster, T.J. Biomaterials, 2005, 26(16), 3075.