Evaluations of poly(vinyl alcohol)/alginate hydrogels cross-linked by γ-ray irradiation technique

Abstract

In this work, we prepared hydrogels for wound dressing from a mixture of poly(vinyl alcohol) (PVA) and alginate using the 60 Co γ-ray irradiation technique. We examined the physical properties of these hydrogels, including gelation, water absorptivity, and gel strength, to evaluate the applicability of these hydrogels for wound dressings. The biocompatibility of these hydrogels was also evaluated in vitro, in cultures of mouse fibroblasts, and in vivo, by subcutaneous implantation studies in rats. The gel content and strength increased upon increasing the radiation dose and upon decreasing the concentration of alginate. The degree of swelling was inversely proportional to the gel content and strength. The degree of cytotoxicity of the γ-ray-treated hydrogels was ca. 60% compared to the (-) control (serum) after 1 day of incubation. When the incubations were prolonged up to 2 days, the toxicity of all the samples decreased remarkably and reached that of the control. Subcutaneous implantation studies in rats indicated that foreign body reactions occurring around the implanted hydrogels were moderate and became minimal upon increasing the implantation time.

Properties of Sodium Alginate–Polyvinyl Alcohol Hydrogels Irradiated By Gamma Ray For Wound Dressing Materials

“…Finally, the hydrogels were taken out from the shaker and dried in oven at 60 °C until a constant weight (W f ). Gel fraction was calculated gravimetrically (Nam et al, 2004) ). Dried hydrogels were soaked in distilled water at room temperature.…”

“…Nam et al (2004) reported that they obtain the gel fraction in the range of 80-95% from the SA-PVA hydrogel. It means that the higher the irradiation dose, the closer the crosslinking formed, hence only a small amount of available substances were water soluble.…”

“…It was because there was a lot of SA degraded and finally it didn't form a crosslinking or copolymerization and therefore it dissolved in water and lost. Nam et al (2004) used the alginate content of 1%, 3%, and 5% in the mixture of SA-PVA hydrogels with the total mix of 15 % SA-PVA in hydrogels, with irradiation dose of 25 kGy, 35 kGy, and 50 kGy. They obtained, at certain irradiation dose the higher the SA content, the lower the gel fraction resulted.…”

“…It is used in various pharmaceutical, biomedical, and other industrial fields, e.g. as an immobilization matrix in biotechnology field (Lee & Mooney, 2001;Hoffman, 2002;Bahrami et al, 2003;Nam et al, 2004;Mishra et al, 2007;Zain et al, 2011). However, as a biomaterial, PVA is brittle therefore it needs to be combined with other polymer or by copolymerization, e.g.…”

“…Utilization of gamma ray or electron beam irradiation was more popular among those methods of polymerization process because there is no neccessity to use crosslinker and initiator, which may be harmful and difficult to remove. In addition, the irradiation technique is easy to control in processing and possesses the possibility of combining hydrogels formation and sterilization in one technological step (Nam et al, 2004;Stasko et al, 2009). Nam et al (2004) produced a mix of SA-PVA hydrogels with the total mix of SA-PVA in hydrogels was 15%, the SA content in the mix of SA-PVA was 1%, 3%, and 5%, and the irradiation dose was 25 kGy, 35 kGy, and 50 kGy.…”