Naturally derived biofunctional nanofibrous scaffold for skin tissue regeneration

https://doi.org/10.1016/j.ijbiomac.2014.04.031Get rights and content

Abstract

Significant wound healing activity of Aloe vera (AV) and higher elastic strength of Silk fibroin (SF) along with mammalian cell compatibility makes AV and SF an attractive material for tissue engineering. The purpose of the present work was to combine their unique properties, with the advantage of electrospinning to prepare a hybrid transdermal biomaterial for dermal substitutes. The physico-chemical characterization of the developed scaffold showed finer morphology expressing amino and esteric groups with improved hydrophilic properties and favorable tensile strain of 116% desirable for skin tissue engineering. Their biological response showed favorable fibroblast proliferation compared to control which almost increased linearly by (p < 0.01) 34.68% on day 3, (p < 0.01) 19.13% on day 6, and (p < 0.001) 97.86% on day 9 with higher expression of CMFDA, collagen and F-actin proteins. The obtained results prove that the nanofibrous scaffold with synergistic property of AV and SF would be a potential biomaterial for skin tissue regeneration.

Introduction

Skin is the largest protective barrier of human body. Skin regenerate itself when subjected to minor injuries however severe damages like full thickness dermal loss require effective clinical treatment failure of which may lead to mortality [1]. Surgical approaches like auto grafts remains the main treatment for thermal injury related skin loss however severe burn patients lack tissue availability requiring an alternative method of skin replacement [2]. Emergence of tissue engineering therapeutic means has attracted much attention as it offers a better solution to overcome the drawbacks of current limitation in skin transplantation which focuses on regeneration of neotissues from cells with the support of biomaterials and growth factors [3]. The cells, scaffold and growth factor are the three key materials for tissue engineering [4]. Scaffolds are artificial structure capable of supporting and providing a native environment for the cell adhesion and proliferation to form tissues [5], [6].

Several ways available for scaffold production of which electrospinning remains the predominant choice as it can produce materials with nanoscale properties [7] mimicking the architecture of the native extracellular matrix [8]. Polymeric scaffold of different origin (natural and synthetic) have been investigated for scaffold development [9], [10]. Natural materials like collagen, fibrin and chitosan are rich in growth factors and are ideal for promoting skin tissue regeneration but are not mechanically strong when electrospun on the other hand biodegradable synthetic materials such as Polycaprolactone (PCL), Poly(L-lactic acid) (PLLA) are stronger, but lack growth factor for tissue regeneration [11], [12], [13]. The major challenges in scaffold fabrication for dermal regeneration are the need for both complex functionality and biomechanical stability. The alternative solution for the above issue can be overcome by physical hybridizing of polymers (natural biopolymers or synthetic polymers) for a synergistic actions and then converting them into nanofibers which can impart bioactivity and improved mechanical property to the resulting scaffold.

Silk fibroin is a natural protein isolated from silkworm (Bombyx mori) containing two main proteins, sericin (outer covering) and fibroin (central structure). Fibroin does not induce immune rejection unlike other bio-derived proteins and hence being focused for biomedical applications. Additionally fibroin has many unique properties like strong mechanical stability; biocompatibility and slow degradability. Research findings have shown fibroin based scaffolds mimic the extracellular matrix and efficiently support cell attachment and proliferation of fibroblasts [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25]. Aloe vera based dermatological treatment have been practised traditionally for centuries especially for wounds, burns, insect sting, and skin inflammation [26], [27], [28]. Anti-oxidant, anti-inflammatory, anti-microbial, immunomodulatory properties of aloe vera has highlighted its application in biomedical applications. Mannose 6-phosphate and acemannan are the important components responsible for many therapeutic properties of Aloe vera which mediate cell signaling pathway for proliferation of fibroblast [29], [30]. It promotes epithelialization and collagen synthesis for effective wound healing [31], [32], [33], [34].

Human fibroblast cells need higher elastic support due to their elongated morphology. In present study for scaffold fabrication PLACL was used which has higher tensile properties compared to PCL and Silk Fibroin was used to further increase the mechanical strength of the fabricated scaffolds as silk fibroin has unique mechanical and biological properties and Aloe vera was used for its wound healing property. Physico-chemical and biological characterization of the hybrid scaffolds are investigated for its enhanced ability towards wound healing and tissue regeneration.

Section snippets

Fabrication of PLACL, PLACL-SF, PLACL-SF-AV and PLACL/Collagen scaffolds

PLACL was dissolved in DCM: DMF (3:1) (Sigma-Aldrich, St. Louis, USA) to form 10% solution and kept in stirring overnight. PLACL-SF solutions were prepared by dissolving 8% PLACL and 4% lyophilized Silk Fibroin powder (Xi’an Yuensun Biological Technology Co., Ltd, China) in DCM: DMF (3:1). Similarly PLACL-SF-AV solution was prepared by dissolving 8% PLACL followed by addition of 4% silk fibroin powder and 4% Aloe vera powder (Xi’an Yuensun Biological Technology Co., Ltd, China) in DCM:DMF

Characterization of nanofibrous scaffolds

The morphology of nanofibrous scaffolds were analyzed by FESEM. Fig. 1 (a–d) shows the FESEM micrographs of PLACL, PLACL-SF, PLACL-SF-AV and PLACL/Collagen nanofibrous scaffolds.

Fiber diameters were calculated from the FESEM pictures using the ImageJ analysis software. The average fiber diameter of PLACL, PLACL-SF, PLACL-SF-AV and PLACL/Collagen nanofibers were in the range of 515 ± 43, 460 ± 32 nm, 212 ± 27 nm and 233 ± 54 nm, respectively and results were tabulated in Table 1.

Similar to the PLACL

Conclusion

Electrospinning of multiple natural polymer blends can yield a mixture of natural nanofibers that closely mimic the native ECM. A large percentage of native tissues contains both protein and polysaccharides fibers that are frequently subjected to tensile and elastic loading, respectively. Electrospun fibrous scaffolds composed of silk fibroin and aloe vera have been fabricated to replicate the native ECM of human skin. PLACL-SF-AV scaffold supports fibroblast proliferation and produces distinct

Acknowledgment

This study was supported by the Department of Textile Technology, Anna University, Chennai, India and National University of Singapore, Singapore.

References (40)

  • X.Y. Li et al.

    Mater. Lett.

    (2012)
  • F.J. O’Brien

    Mater. Today

    (2011)
  • J. Gunn et al.

    Trends Biotechnol.

    (2010)
  • Q. Lu et al.

    Biomaterials

    (2007)
  • Y. Wang et al.

    Biomaterials

    (2006)
  • B.M. Min et al.

    Int. J. Biol. Macromol.

    (2004)
  • Y. Yang et al.

    Biomaterials

    (2007)
  • G.H. Altman et al.

    Biomaterials

    (2003)
  • N. Minoura et al.

    Biochem. Biophys. Res. Commun.

    (1995)
  • S. Fan et al.

    Int. J. Biol. Macromol.

    (2013)
  • T. Reynolds et al.

    J. Ethnopharmacol.

    (1999)
  • P. Krishnan

    Curr. Anaesth. Crit. Care

    (2006)
  • S. Talukdar et al.

    Biomaterials

    (2011)
  • S. Peter

    Burns

    (2001)
  • S.A. Bishara et al.

    Burns

    (2005)
  • Y. Ikada

    J. Royal Soc. Interfaces

    (2006)
  • B.P. Chan et al.

    Eur. Spine J.

    (2008)
  • P. Hetel et al.

    Trends Biomater. Artif. Organs

    (2011)
  • T. Lu et al.

    Int. J. Nanomed.

    (2013)
  • R. Vasita et al.

    Int. J. Nanomed.

    (2006)
  • Cited by (64)

    • Promoting keratocyte stem like cell proliferation and differentiation by aligned polycaprolactone-silk fibroin fibers containing Aloe vera

      2022, Biomaterials Advances
      Citation Excerpt :

      The mean fiber diameter was reduced after higher percentages of AV up to 5%. It should be noted that reducing in fiber diameter could be related to the high electrostatic conductivity of AV [31,32]. On the other hand, the fiber diameter was increased after addition of 7.5% of AV which may be the result of lower homogeneity of the mixer due to lack of heterocyclic complexes formation between AV and PCL-SF bonds [32].

    • Drug delivery systems based on nano-herbal medicine

      2022, Bionanotechnology: Emerging Applications of Bionanomaterials
    • Engineering of biopolymer-based nanofibers for medical uses

      2021, Tailor-Made and Functionalized Biopolymer Systems: For Drug Delivery and Biomedical Applications
    View all citing articles on Scopus
    View full text