The Effects Of Liquid Bandage Formed Nano-porous Membrane On Cutaeous Wound Healing And The Research Of Molecular Mechanism

Wound dressings are very important for cutaneous wound healing. An ideal wound dressing should have good mechanical properties to protect wound from external mechanical damage, be suitable for any irregular size of wounds, have anti-bacterial properties to reduce the inflammatory, be no-toxicity and non-irritation and be easy removed from wound. What’s more, it should provide a desired condition, especially a moist environment for wound healing. Nitrocellulose wound dressing, especially be used for liquid bandage, has a long history in medical field. Nitrocellulose liquid bandage is popular with customers due to its flexible, comfortable and suitable for protecting any wounds. Moreover, the liquid bandage formed membrane appears colorless and transparent which is most favorable for watching the process of wound healing. However, nitrocellulose liquid bandage is not approved for producing in China, thereby, the effects and mechanisms of liquid bandage on wound healing are not reported in any references.In this study, we obtained nano-porous membrane formed by liquid bandage which utilized ethyl acetate as solvent, nitrocellulose as membrane-forming materials, non-toxic acetyl tributyl citrate as a plasticizer, additional benzyl alcohol as antibacterial agents and analgesics, benzalkonium chloride as the antimicrobial agent. Further, we investigated the effects and mechanisms of liquid bandage on wound healing.Firstly, we tested the physical properties of liquid bandage. SEM test results indicated liquid bandage formed membrane had dense porous and the pore size is about 18.20 nm. Bacterial permeation test showed that the liquid bandage formed membrane was beneficial for preventing bacterial permeation. WVTR of liquid bandage formed membrane showed it could keep a moist environment for wound healing. FTIR test results revealed that liquid bandage formed membrane contained OH structure that helped to absorb water and maintained moisture of the wound, which promoted cell growth. liquid bandage formed membrane had a water contact angle of approximately 70°, an advantageous angle for cell growth. What’s more, liquid bandage formed membrane had good mechanical properties, the tensile strength and percentage elongation at the breaking point of liquid bandage with 0.034 mm thickness were 6.30N/mm2 and 127.25%, respectively.Secondly, liquid bandage had good biological properties. It was non-bacterial, and had a good anti-bacterial property against Escherichia Coli(E.coli). What’s more, it showed light irritation for SD rats and non-toxicity for the growth of 3T3-Swiss albino.To understand the effects of liquid bandage on wound healing, we used mice’s skin full-thickness wound model and then tested the wound closure and the change of cells or cell factors after treated by liquid bandage. The results showed that the size of the wound treated by liquid bandage were evidently smaller than the naturally healing wounds(model-L) and the wounds treated by solid Band-aid(control). The wounds treated by liquid bandage healed 2-4 days earlier than wounds treated by Band-aid, 4-6 days earlier than the untreated wounds, with relatively good healing qualities as well(macroscopic observation). The results of immunohistochemistry showed that inflammatory cells significantly reduced and regeneration of the epidermis accelerated of wounds treated by liquid bandage. Meanwhile, TGF-β1 was expressed earlier in fibroblasts and keratinocytes, angiogenesis and fibroblasts differentiation towards myofibroblasts, and collagen was faster synthesis and deposition of wounds treated by liquid bandage. Western blot results revealed that inflammatory cells reduced in liquid bandage treatment wounds while proinflammatory cytokines, chemokines Ccl2 and cytokines TNF-α decreasd also. Besides, healing tissue, mechanical properties tests showed 21 days post treatment, the tensile strength at the break point of the healing tissue of liquid bandage treated groups reached 65.67% of normal tissue, whereas that of the Band-aid groups were 42.58%, and that of the untreated groups were only 28.09%.In conclusion, these results suggested that liquid bandage has good physical and biological properties and can promote wound healing process. There are great chances for liquid bandage to become the priority as a fine wound dressing for protecting superficial cutaneous wounds.