Enhanced wound repair ability of arginine-chitosan nanocomposite membrane through the antimicrobial peptides-loaded polydopamine-modified graphene oxide

Abstract

Skin wound healing is a complicated and lengthy process, which is influenced by multiple factors and need a suitable cellular micro-environment. For skin wound, wound dressings remain a cornerstone of dermatologic therapy at present. The dressing material can create an effective protective environment for the wound, and the interactions between the dressing and the wound has a great impact on the wound healing efficiency. An ideal wound dressing materials should have good biocompatibility, moisturizing property, antibacterial property and mechanical strength, and can effectively prevent wound infection and promote wound healing. In this study, in order to design wound dressing materials endowed with excellent antibacterial and tissue repair properties, we attempted to load antimicrobial peptides onto dopmine-modified graphene oxide (PDA@GO) using lysozyme (ly) as a model drug. Then, functionalized GO was used to the surface modification of arginine-modified chitosan (CS-Arg) membrane. To evaluate the potential of the prepared nanocomposite membrane in wound dressing application, the surface morphology, hydrophilic, mechanical properties, antimicrobial activity, and cytocompatibility of the resulting nanocomposite membrane were analyzed. The results revealed that prepared nanocomposite membrane exhibited excellent hydrophilic, mechanical strength and antimicrobial activity, which can effectively promote cell growth and adhesion. In particular, using PDA@GO as drug carrier can effectively maintain the activity of antimicrobial peptides, and can maximize the antibacterial properties of the nanocomposite membrane. Finally, we used rat full-thickness wound models to observe wound healing, and the surface interactions between the prepared nanocomposite membrane and the wound. The results indicated that nanocomposite membrane can obviously accelerated wound closure, and the wounds showed reduced inflammation, improved angiogenesis and accelerated re-epithelialization. Therefore, incorporation of antimicrobial peptides-functionalize graphene oxide (ly-PDA@GO) into CS-Arg membrane was a viable strategy for fabricating excellent wound dressing. Together, this study not only prepared a wound dressing with excellent tissue repair ability, but also provided a novel idea for the development of graphene oxide-based antibacterial dressing.

Keywords: Antimicrobial peptides; Arginine; Chitosan; Graphene oxide; Wound dressing.

Scheme 1

Schematic illustration of the preparation of the CS-Arg nanocomposite membrane modifed with ly-PDA@GO coating and its application for wound treatment

Fig. 1

a TEM images of GO and PDA@GO, bar lengths are 500 nm; b The dispersion of GO (left) and GO@PDA (right) in ethanol after 6 h; c X-ray diffraction pattern of GO and PDA@GO; d Lysozyme adsorption effciency of GO and PDA@GO, P < 0.05, n = 3

Fig. 2

A SEM and AFM images of CS, CS-Arg, ly-GO/CS-Arg and ly-PDA@GO/CS-Arg nanocomposite membrane, bar lengths are 20 μm (SEM) and 5 × 5 μm (AFM). B Water contact angle and C tensile strength of CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d) nanocomposite membrane, P < 0.05, n = 3

Fig. 3

A Relatively antibacterial efficiency of different nanocomposite membrane, and B fluorescence micrographs of S. aureus and E. coli stained by PI & calcein after treatment with CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d), Scale bar lengths are 100 μm, P < 0.05, n = 3

Fig. 4

A Cell proliferation, B area fraction and C morphology of NH3T3 cells cultured on CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d) nanocomposite membrane, Scale bar lengths are 200 μm, P < 0.05, n = 3

Fig. 5

A Photographs of the wound closure and B the schematic diagram of wounds closure on different time point; C Quantitative statistical analysis of wounds closure for CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d) tretment, P < 0.05, n = 3

Fig. 6

Histological appearance of wounds harvested on days 12 of each group, CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d), scale bar lengths are 200 μm

Fig. 7

A Sirius red staining and C the COL I/COL III area ratio in the wound-healing region at 12 days after CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d) treatments, Magnification, 200×, P < 0.05 (n = 3). B Immunofluorescence images and D the quantitative statistical analysis of VEGF relative area percentage in the wound-healing region at 12 days after CS (a), CS-Arg (b), ly-GO/CS-Arg (c) and ly-PDA@GO/CS-Arg (d) treatments, scale bar lengths are 200 μm, P < 0.05 (n = 3)