1. Introduction
Assisting
wounds healing with high efficacy is a research hotspot in the
regenerative medicine. (Ying et al.,
2019) In recent years, various types of wound-dressing materials
containing growth factors to biomimetic extracellular matrix (ECM) have
been more widely adopted to accelerate wound perfectly
healing.(Choi et al., 2018;
Thönes et al., 2019) Although extensive
studies have been carried out around skin repair, but developing newer
biodegradable dressings to promote wound healing are still enormous
market demand.(Zoe, Elizabeth, June, &
Louise, 2019) In particular, epidermal growth factor (EGF) plays key
roles in skin wound repair.(J. et al.)
Besides, as the most abundant ECM structural protein, collagen has good
biocompatibility and degradability, and are considered as a better
constituent for wound dressing
preparations.(Davison-Kotler, Marshall, &
Garcia-Gareta, 2019) We constructed a freeze-dried dressing based on
recombinant human-like collagen (RHC) and EGF to confer a
multifunctional product which can improve cell-biomaterial interactions
and promote wound healing.
EGF is a typical growth factor that has been studied more in wound
repair, which can bind to cell membrane receptors and exert various
biological effects.(Duy et al.;
Jones & Rappoport) In terms of the
mechanism for promoting wound healing, one is that EGF are very powerful
and can significantly promote keratinocytes and so on, and thus migrate
to the injured site;(Jones & Rappoport;
Schreier, Gekle, & Grossmann) the other
is that as a mitogenic promoter, EGF promotes epithelial cell
proliferation and division, improves collagen construction and regulates
protein synthesis, thereby accelerating wound
healing.(Berlanga-Acosta;
Bodnar & J.;
Lian & Li) In brief, EGF plays an
essential role in wound healing .
Among
recently available dressings, collagen-based dressings have shown to
actively influence the healing process by intervening with various
tissue components(Giriprasath et al.).
Type I collagen can form fibrils through heterogeneous self-assembly
compared with type II and type III collagen.
(Irawan, Sung, Higuchi, & Ikoma, 2018;
Jiang et al., 2016;
Tiku & Madhan, 2016) Therefore, it is
widely used as a biological material other than type II and type III
collagen.(Sharma et al., 2017) However,
the application of natural type I collagen is limited for its
insolubility in water and poor processability. With the development of
gene engineering,
a
series of highly hydrophilic, safe and effective recombinant human-like
collagen (RHC) had attracted extensive attention worldwide. Many reports
have been reported to expressed recombinant truncated type I human-like
collagen peptides inE.coli ,(Guo et al., 2010;
Yang et al.) whereas some of studies
expressed recombinant type I human-like collagen peptides containing
multiple identical motifs by means of codon
optimization.(Olsen et al., 2005;
Yao, Yanagisawa, & Asakura, 2004)
Because these motifs are ligands for some types of integrin receptors,
recombinant type I human-like collagen peptides is not only expected to
enhance cell activity through certain integrin receptor binding, but
also is extensible in various fibrous structural materials, including
dressing.(Grab, Miles, Furcht, & Fields,
1996; Mashiko et al., 2018)
In this study, RHC consisting of
cell adhesion domains derived from native type I collagen were designed
and constructed by a genetic engineering method to construct a new type
of RHC to overcome the deficiency of natural animal collagen. In
addition, we prepared RHC/EGF freeze-dried dressing, and its potential
applications for wound healing and repair were investigated using anin vivo full-thickness skin defects. Our results demonstrate that
RHC/EGF freeze-dried dressing are a potentially useful tool for wound
healing applications.