A study on hyaluronic acid/hydroxyethyl cellulose tissue engineering scaffold for wound healing

A study on hyaluronic acid/hydroxyethyl cellulose tissue engineering scaffold for wound healing
Atefeh Derakhshani,^1,* Saeed Hesaraki,² Nader Nezafati,³ Mahmoud Azami,⁴
1. Nanotechnology and advanced materials, Materials and energy research center, Karaj, Iran
2. Nanotechnology and advanced materials, Materials and energy research center, Karaj, Iran
3. Nanotechnology and advanced materials, Materials and energy research center, Karaj, Iran
4. Tissue engineering department, School of advanced technologies in medicine, Tehran university of medical sciences
Introduction: Wound healing is an active process including several phases and procedures for recovering epidermal tissue and cellular structures of injured site to its initial function and formation (Choi et al. 2008). Hydrogels are typically composed of hydrophilic polymers, such as hyaluronic acid (HA) and hydroxyethyl cellulose (HEC). Swollen hydrogels absorb large quantities of water without dissolution and they feature unique structural properties, which are similar to those of tissues and the extracellular matrix (ECM) of the skin. The unique properties of hydrogels, make them suitable for applications as biomaterials for scaffolds in the tissue engineering (Kwon et al. 2015). In modern fashion of wound management systems, one of the most important factors to achieve healing quickly is a moist environment. This condition mounting migration of epidermal cells with enhanced laid-up of necrosis tissue and fibrin, promoting angiogenesis, and collagen synthesis, provoking fibroblast mitosis (Katz et al. 1991).
Methods: Hyaluronic acid (average Mw = 1.2 MDa) was a kind gift from Chitotech (Tehran, Iran). Hydroxyethyl cellulose (average Mw = 90,000 Da) was purchased from Sigma Aldrich (USA). ɣ- glycidoxypropyltrimethoxysilane (GPTMS) was purchased from MERCK (USA). Scaffold preparation HA/HEC complex hydrogel was prepared by weight ratio of HA to HEC by 50:50 which was coded as HA50-HEC50. They were dissolved completely in 20 mL deionized water by stirring, to achieve a homogeneous solution (rpm: 250, for 6 h at room temperature). Then, the GPTMS cross-linking agent was added drop-wisely into the solution with a 10% (w/w) of polymers and further stirred (rpm: 100, for 48 h at 60˚C). Then, the obtained solution poured into a petri dish and pre-frozen at -80˚C in a deep freezer. The frozen samples were lyophilized (FD-10, Pishtaz Engineering Co. Iran) at a temperature of -58 °C and pressure 0.5 torrs for 48 hours.
Results: Scanning Electron Microscopy (SEM) Fig. 1 demonstrated the surface morphology of the scaffold, which was conducted by using SEM. The scaffold structure exhibited heterogeneous porous patterns. It depicted that pores were continuous and well interconnected and the average pore size was in the range of 50-120μm, which leads to a large swelling ratio (Kim et al. 2003). Swelling ratio (%) Properties of the swelling behavior of the scaffold were determined by (Türe 2019) as shown in Fig. 2. The swelling ratio was found to 1650% and then reached to 2500% in 6 hours. The swelling of super-porous structure is due to capillary forces, which lead to rapid uptake of water that exists mainly as free water (Omidiana et al. 2005). Hydrophilic groups of HA ( COOH, OH), HEC (OH), and GPTMS (OH) were other reasons for enhancing this ratio. GPTMS with longer molecular chains (epoxy) would provide the structure with more ability to expand and swell (Poursamar et al. 2016). The ability of the scaffold to absorb a large quantity of water helps to hydrates the wound and absorbed excess wound exudate. In vitro wound healing The results demonstrate that scaffold significantly enhanced the migration rate of L929 cells and that after 24 h the wounded area in presence of scaffold was closed by 65% compare to control and positive control (culture medium) (Fig. 3). The obtained images were quantitatively analyzed with the WimScratch online software program. The migration rate of fibroblast cells towards the wounded site is an important factor that can accelerate the healing process after injury which were happened due to moist environment.
Conclusion: In this study, we prepared a super porous tissue engineering scaffold for wound healing. It exhibited the large water uptake due to functional groups, structure, and high pour size. Moreover, the scaffold exhibited remarkable in vitro wound contraction potential in terms of improved fibroblast cell migration.
Keywords: Hyaluronic acid, Hydroxyethyl cellulose, Wound healing, Tissue engineering,