Research Article: Evaluation of wound healing effect of alginate film containing Aloe vera gel and cross-linked with zinc chloride 1

Date Published: July 03, 2020

Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia

Author(s): Adriana Yuriko Koga, Julio César Felix, Rodrigo Gomes Marques Silvestre, Leandro Cavalcante Lipinski, Bruna Carletto, Fernanda Alexia Kawahara, Airton Vicente Pereira.


To develop a new wound dressing composed of alginate and Aloe vera gel and cross-linked with zinc ions.

The aloe-alginate film was characterized using scanning electron microscopy (SEM), swelling profile, mechanical properties, polysaccharide content and X-ray diffraction (XRD). Thirty Wistar rats were divided in two groups a) treated with aloe-alginate film and b) control (treated with sterile gauze). Wound contraction measurements and hystological analysis were performed on 7th, 14th and 21st days after wound surgery.

The aloe-alginate film presented adequated mechanical resistance and malleability for application as wound dressing. There was no statistical difference in wound contraction between two groups. Histological assay demonstrated that aloe-alginate film presented anti-inflammatory activity, stimulated angiogenesis on proliferative phase and a more significant increased in collagen type I fibers and decreased type III fibers which promoted a mature scar formation when compared to control.

The aloe-alginate film showed adequate physicochemical characteristics for wound dressing applications. The in vivo assay demonstrated that aloe-alginate film enhanced the healing process of incisional skin wounds.

Partial Text

Chronic wounds such as diabetic ulcers, pressure ulcers and venous ulcers affect the quality of life of patients and have a great economic and social impact. The cost increases with the population aging and the incidence of chronic diseases like obesity and diabetes1 .

SEM analysis was performed using a MIRA3 LM, Tescan Orsay Holdingn electron microscope. Prior to analysis, the film samples (cross-linked and non-cross-linked films) were covered with a thin layer of gold by spraying and disposing of a maximum distance to avoid damage to the surface. All the samples were examined using an accelerating voltage of 10 kV.

X-ray diffraction of cross-linked and non-cross-linked aloe-alginate films was performed using an Ultima IV/Rigaku. A scanning rate of 5°/min and range of 3-90° were applied at room temperature.

All the experiments were approved by the Ethics Committee on Animal Experimentation of UEPG, registry number 041/2017. Thirty male Wistar rats (250 g) were divided into the following two groups (n=15): (a) aloe-alginate film and (b) control (sterile gauze). The rats were anesthetized with an i.p. injection of ketamine (40 mg/kg) and xylazine (5 mg/kg).

Tissue of wounds were collected on 7th, 14th, and 21st days and included in paraffin. The tissues samples were cut at a thickness of 3 μm and stained with hematoxylin-eosin. Inflammatory changes and angiogenesis were then observed in three fields under 40 times magnification using a conventional light microscope Olympus. The images were captured using cellSens Standard software. Cell counter image J software was used to count inflammatory cells and blood vessels.

The statistical analysis was performed using analysis of variance (ANOVA) for multiple comparisons, followed by Tukey’s test with a confidence interval of 95% (p ≤0.05).

Aloe vera ( Aloe barbadensis Miller) is a popular medicinal plant for wound healing. Aloe gel contains about 98% of water and polysaccharides constitute 55% of dry matter15 . Acemannan, the major polysaccharide extracted from Aloe vera gel, can stimulate macrophages activation and promote the release of cytokines from fibroblasts16 . The beneficial properties of acemannan in wound healing have been reported17 .

Aloe-alginate film presented adequate physicochemical characteristics for application as wound dressing. The new aloe-alginate film cross-linked with zinc chloride modulated inflammatory phase, increased angiogenesis on proliferative phase and collagen type I suggesting that aloe gel combined with zinc ions contributed to the wound healing process and a better scar formation.




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