Volume 28, Issue 10 (12-2021)                   RJMS 2021, 28(10): 40-57 | Back to browse issues page

Research code: 960078
Ethics code: 1395.377
Clinical trials code: 960078

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Norouz-Gohari F, Nikkhoo M, Tehrani P, Shojaei S. Effects of 8-week Interval and Continuous Training on Brain-Derived Neurotrophic (BDNF) and Insulin-like Growth-1 (IGF-1) in Wistar Male Rat. RJMS 2021; 28 (10) :40-57
URL: http://rjms.iums.ac.ir/article-1-6290-en.html
Department of Biomedical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran , shahrokh.shojaei@gmail.com
Abstract:   (1127 Views)

Background & Aims: Wound dressing materials allocate a great portion of skin and draught maintenance in the global medical market.  In previous times the conventional dressing materials as natural and synthesized bondage, Cotton and gas were used for caring of skin wounds. Nowadays the production of modern wound dressing of higher restorative capabilities has attracted the attentions. These modern wound dressing can precipitate the re-epithelization, collagen synthesis and angiogenesis. These modern wound dressing materials can reduce the PH and perform as a barrier to bacterial penetration. There are several methods available for production of fibers and nanofibers. Between these methods electrospinning has attracted much interests. By this procedure it is possible to produce composite fibers and porous mats. The cells can penetrate to these pores and grow appropriately. The manufactured fibers usually have proper uniformity and the dimensions can vary from several nanometers to micrometers. These fibers can be used in different applications such as the filters, the fortifiers, the scaffolds and the wound dressing materials. The biocompatible materials are among the best choices for fabrication of the wound dressing, They can provide the necessary condition for growth of derma and epidermal layers. The multi-polymers Mat fibers have been used for tissue engineering applications, as they have the capability of the simulation of the extracellular Matrix. Drug addition to these scaffolds can enhance the function of this system and improve the restoration capabilities.  The electrospun wound dressing materials facilitate the tissue growth. The electrospun nano-fibers have similar structures to that of the skin and have higher compatibility with blood. They make the wound and tissue restoration possible.
In this research the production of two layers wound dressing materials has been conducted by the electrospinning Method. The downward layers of these wound dressing materials have been manufactured from polyvinyl alcohol. Polyvinyl alcohol is a synthetic polymer which has proper electrospinning properties, and therefore it can be used for nanofibers production. The fibers have high tensile strength and an appropriate flexibility. This material is one of the oldest and most common materials that have been utilized for drug delivery systems, wound dressing and wound maintenance, contact lens and artificial limbs. This polymer is biocompatible, and due to the hydroxyl groups, it has reasonable water absorption. Also for infection inhibition vancomycin drug has been loaded in this layer.
Methods: Many different wound dressing fabrication methods have been used for many years. Among these techniques, electrospinning has attracted a lot of attention. This simple and cost-effective method produces nano and micro fibers substrates which simulate extracellular matrixes and provide a suitable porous structure for cell adhesion and proliferation. In this study, electrospinning was used for the fabrication of two-layer wound dressing, consisted from chitosan and poly (lactide-co-glycolide) acid (PLGA) as the first layer and polyvinyl alcohol (PVA) and vancomycin as the second layer. For the first layer electrospinning, the solution of chitosan, poly-lactic co-glycolic acid has been provided and transmitted to 5 ml syringe and located in the place.  the syringe tip attached to the electrical current source and the electrospun fibers were collected it on a aluminum foil covered collector. The ejection action was performed by the flow rate of 2 ml per hour and the electrospun fibers were manufactured on a 50 mm diameter collector.  In this research, the distance between the nozzle and the collector was 120mm and the rotating speed of the collector was 16 RPM. The device voltage was set at 15 kilovolts. For electrospinning of the second layer the solution of polyvinyl alcohol and vancomycin was provided and transmitted into 5ml syringe, just like previous steps.  The injection process was performed by the volume rate of 1 ml per hour and electrospun fibers were gathered on the 15 mm diameter collector.  In this level, the distance between the nozzle and the Collector was 200mm, the rotating speed was 10 RPM and the device voltage was set at 15 kilovolts. For cross-linking, the samples were located on the vapor of glutaraldehyde and HCL by the molar ratio of 1:10 for 12 hours.
Results: Electrospun two layer wound dressing microstructure was evaluated by scanning electron microscopy (SEM). It was observed that both layers have homogenous bead free interconnected porous structures. Image measurement software revealed that fiber diameters ranged from 0.2 to 1.2 micrometer, which can provide a proper substrate for cell proliferation. Functional groups of raw materials and chemical bonding between layers were assessed by FTIR analysis. In order to evaluate layers absorption capacity, they were soaked in PBS solution for 24 hours. They showed about 112.4±10.2 % PBS absorption after 24 hours. So they can absorb wound secretions and keep the wound environment dry. Biodegradation tests showed that 32.7 % of these two layer wound dressing was degraded after 3-weeks immersion in PBS solution. Drug release tests demonstrated a burst release of vancomycin in the first hours which followed by decreasing releasing rates. These releasing manner lowered infection appearance in the wound site. Antibacterial activity is an important factor in wound dressing and the co-existence of chitosan and vancomycin provided approximately 98.72 % bacterial reduction in the antibacterial assay. Although the antibacterial test showed a significant reduction in bacterial growth, the MTT test showed that these scaffolds are biocompatible and provide a favorable environment for cell attachment and proliferation.
Conclusion: The images of the microstructure electrospun substrates depicted that electrospun two-layer polyvinyl alcohol vancomycin and poly lactic co-glycolic acid chitosan substrate has a porous fiber structure, in a way that these pores are interconnected.  The fibers of two layers have no beads and they have relatively homogeneous distribution. The water absorption of these scaffolds showed suitable inflation strength in 24-hours of submerge in phosphate buffer saline.  Also the degradation capability of the samples demonstrated the approximately 32% degradation of the structure in 3-weeks.  It illustrated convenient degradation time of wound dressing and it is in good correspondence with previous researchers. Drug delivery assessment of vancomycin from these samples was relatively explosive in the initial hours.  But it reached an equilibrium state in some hours.  The initial explosive delivery can lead to eradication of the initial bacteria and it is a key factor in wound dressing applications. The antibacterial assessment of their structure demonstrated high antibacterial capabilities due to the existence of chitosan and vancomycin in these scaffolds. About 98% of the batteries at the dose of 10 mg/lit were perished.  Also the cellular viability investigation for these scaffolds proved non-toxicity and biocompatibility. The cultured cells on the scaffolds had normal morphology. According to acquired results in this study, it seems that these two layer electrospinning substrates can be useful for wound healing.

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Type of Study: Research | Subject: Biotechnology

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