Page 56 - _NIPER-G Annual Report 2019-201

Research Area-6

Silkworm silk scaffolds functionalized with recombinant spider silk containing a
fibronectin motif promotes healing of full-thickness burn wounds (Collaboration with
IIT Guwahati)
Full-thickness cutaneous wounds, such as deep burns, are complex wounds that often require
surgical interventions. Herein, we show the efficacy of acellular grafts that can be made
available off-the shelf at an affordable cost using silk biomaterials. Silkworm silk fibroin (SF),
being a cost-effective and natural biopolymer, provides essential features required for the
fabrication of three-dimensional constructs for wound-healing applications. We report the
treatment of third-degree burn wounds using a freeze-dried microporous scaffold of Antheraea
assama SF (AaSF) functionalized with a recombinant spider silk fusion protein FN-4RepCT
(FN-4RC) that holds the fibronectin cell binding motif. In order to examine the healing
efficiency of functionalized silk scaffolds, an in vivo burn rat model was used, and the scaffolds
were implanted by a one-step grafting procedure. The aim of our work is to investigate the
efficacy of the developed acellular silk grafts for treating full-thickness wounds as well as to
examine the effect of recombinant spider silk coatings on the healing outcomes. Following 14-
day treatment, AaSF scaffolds coated with FN-4RC demonstrated accelerated wound healing
when compared to the uncoated counterpart, commercially used DuoDERM dressing patch,
and untreated wounds. Histological assessments of wounds over time further confirmed that
functionalized silk scaffolds promoted wound healing, showing vascularization and re-
epithelialization in the initial phase. In addition, higher extent of tissue remodeling was affirmed
by the gene expression study of collagen type I and type III, indicating advanced stage of
healing by the silk treatments. Thus, the present study validates the potential of scaffolds of
combined silkworm silk and FN-4RC for skin regeneration.

Chouhan D, Lohe TU, Thatikonda N, Naidu VGM, Hedhammar M, Mandal BB. Silkworm silk
scaffolds functionalized with recombinant spider silk containing a fibronectin motif promotes
healing of full-thickness burn wounds. ACS Biomaterials Science & Engineering. 2019 Aug
9;5(9):4634-45.
Graphical Abstract

Figure . Schematic representation: (a) Image of the silk scaffold functionalized with FN-4RC
recombinant spider silk. (b) Illustration of the third-degree burn wound model in the rat system obtained
using a customized metallic heating block. (c) Experimental setup depicting treatment of cutaneous
wounds in the burn rat model using silk scaffolds via one-step grafting procedure. The silk scaffolds
were grafted using skin staples on the excised wounds post 48 h of burn infliction, which were removed
on the third day. The animals assigned in each group of specific time-points were terminated and
marked by (T) for the examination of the wounded tissue.

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