Introduction: Recently, marine collagen has gradually attracted attention because of its abundance and low price[1],[2]. However, it is unclear whether tilapia skin collagen could be prepared as a wound dressing. In this study, tilapia skin collagen nanofibers was developed. The morphological structure, tensile strength and hydrophilicity were characterized. Furthermore, Human keratinocytes (HaCaTs) were chosen to investigate the effects of collagen nanofibers on cell adhesion and proliferation. Finally, Sprague−Dawley (SD) rat models with full-thickness skin defects were used to confirm the ability of collagen nanofibers to accelerate wound healing.
Experimental Section: The tilapia collagen nanofibers were developed by electrospinning. The morphology was observed using scanning electron microscopy (SEM). The tensile strength and the contact angle was analyzed using a universal materials testing machine and a contact anglemeasuring instrument respectively. Then, HaCaTs were seeded on tilapia collagen nanofibers, cell morphology on 24h and proliferation for 1, 3 or 5 d were observed using SEM and MTT assay. Finally, Full-thickness skin defects with a diameter of 2.5 cm were incised on the dorsal of each SD rat. These wounds were covered with tilapia collagen nanofibers. The control group was not covered. The morphology of the wounds was examined at 7 and 14 d.
Results and Discussion: In the present study, tilapia collagen nanofibers were fabricated by electrospinning. SEM showed that the collagen nanofibers were smooth with a diameter of 310 ± 117 nm (Figure 1A).The tensile strength was 6.72 ± 0.44 MPa (Figure 1B), which may met the requirements for human skin. The HaCaTs were firmly attached and proliferated well on the collagen nanofibers (Figure 2A and B). These results may originate from the nanostructure and the excellent hydrophilicity (θ = 21.2°) (Figure 1C). It was reported that a greater number of cells adhered on the nanofibers than on the microfibers[3]. Ultimately, it could be found that the wound-healing rate and the process of re-epithelialization in the collagen nanofibers group was significantly improved compared to the control group, which indicated that collagen nanofibers could effectively pormote wound healing. Therefore, it indicate that they have great potential for clinical application.
Conclusion: In this study, electrospun tilapia collagen nanofibers were successfully developed. The tensile strengh was suitable for application on human skin. The collagen nanofibers could not only promote the adhesion and proliferation of HaCaTs, but also effectively accelerating rat skin wound healing. These effects were associated with the biomimetic structure and hydrophilicity. The study provided a possibility for the future application of tilapia collagen nanofibers in skin regeneration.
Fig.1. Characterization of tilapia collagen nanofibers. (A) SEM images. (B) Stress/strain curves. (C) Contact angle.
Fig.2. Adhesion and proliferation of HaCaTs cultured on tilapia collagen nanofibers. (A) SEM images of HaCaTs cultured for 1 day. (B) Proliferatio of HaCaTs cultured for 1, 3, and 5 days.
This work was supported by grants from Natural Science Foundation of China (nos. 31470917, 31470941).
References:
[1] S. Sankar, S. Sekar, R. Mohan, S. Rani, J. Sundaraseelan and T.P. Sastry, Preparation and partial characterization of collagen sheet from fish (Lates calcarifer) scales, Int J Biol Macromol, 42 (2008) 6-9.
[2] K. Yamamoto, K. Igawa, K. Sugimoto, Y. Yoshizawa, K. Yanagiguchi, T. Ikeda, S. Yamada and Y. Hayashi, Biological safety of fish (tilapia) collagen, Biomed Res Int, 2014 (2014) 630757.
[3] S. Sankar, S. Sekar, R. Mohan, S. Rani, J. Sundaraseelan and T.P. Sastry, Preparation and partial characterization of collagen sheet from fish (Lates calcarifer) scales, Int J Biol Macromol, 42 (2008) 6-9.