Characterization and in vivo evaluation of a fabricated absorbable poly(vinyl alcohol)-based hernia mesh

The most widely taken medical approach toward hernia repair involves the implementation of a prosthetic mesh to cover the herniated site and reinforce the weakened area of the abdominal wall. Biodegradable meshes can serve as biocompatible grafts with a low risk of infection. However, their major complication is associated with a high rate of degradation and hernia recurrence. We proposed a facile and cost-effective method to fabricate a poly(vinyl alcohol)-based mesh, using the solution casting technique. The inclusion of zinc oxide nanoparticles, citric acid, and three cycles of freeze-thaw were intended to ameliorate the mechanical properties of poly(vinyl alcohol). Several characterization, cell culture, and animal studies were conducted. Swelling and water contact angle measurements confirmed good water uptake capacity and wetting behavior of the final mesh sample. The synthesized mesh acquired a high mechanical strength of 52.8 MPa, and its weight loss was decreased to 39 %. No cytotoxicity was found in all samples. In vivo experiments revealed that less adhesion and granuloma formation, greater tissue integration, and notably higher neovascularization rate were resulted from implanting this fabricated hernia mesh, compared to commercial Prolene® mesh. Furthermore, the amount of collagen deposition and influential growth factors were enhanced when rats were treated with the proposed mesh instead of Prolene®.

Biomedical properties and hemostatic efficacy of polyvinyl alcohol (PVA) based hydrogel in experimental rat liver injury model

PURPOSE

Bleeding is a leading cause of mortality and morbidity in the trauma and surgery field, using effective hemostatic agents can help us reduce bleeding especially in parenchymal hemorrhage. Nowadays polyvinyl alcohol (PVA) is known as a safe candidate for wound dressing and maybe a hemostatic agent. PVA-based hydrogel is a popular biocompatible material in the biomedical field especially when it has high water absorption. In this study, we investigated the PVA hydrogel's mechanical and biological properties as well as its hemostatic potential in parenchymal bleeding.

METHODS

PVA hydrogel had made by the freeze-thawing approach, we used PVA hydrogel in comparison to standard treatment to investigate hemostatic potency. Also, we performed MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) tests to survey PVA cellular toxicity. After an acute liver injury, two groups of 12 rats were treated with PVA hydrogel or standard treatment with sterile gauze. The results including the time and volume of bleeding, and the time and survival rate of the rats were measured and compared.

RESULTS

We saw that PVA hydrogel was safe with no cellular toxicity in the MTT assay. Regarding efficacy, PVA hydrogel increased rats' survival after bleeding from 75% to 91.7%, and decreased bleeding time (p: 0.015), and bleeding volume (p: 0.03) compared to the control group.

CONCLUSION

Polyvinyl alcohol is safe. It has good biological properties with no cellular toxicity and has a significant hemostatic effect and can be regarded in control of parenchymal hemorrhage.

Design and fabrication of polyvinylidene fluoride-graphene oxide/gelatine nanofibrous scaffold for cardiac tissue engineering

Polyvinylidene fluoride (PVDF) electrospun scaffolds have recently been developed for cardiac tissue engineering applications thanks to their piezoelectricity. However, PVDFs' hydrophobic nature requires modifications by incorporating natural polymers. In this study, we focussed on the hybrid electrospinning of PVDF and gelatine and the further introduction of graphene oxide nanoparticles to investigate either hydrophilicity or piezoelectricity enhancement and its impact on mouse embryonic cardiomyocytes. The results revealed a nanofibre diameter of 379 ± 73 nm for the PVDF/gelatine/graphene oxide (PVDF-GO-CG) platform, providing excellent tensile strength. Additionally, hydrophilicity was improved by gelatine and GO incorporation compared with pure PVDF. Cellular studies also showed an elongated morphology of cardiomyocytes, similar to the myocardial tissue, as well as high viability and non-toxicity in the PVDF-GO-CG scaffold according to the average survival rate. Furthermore, the expression of connexin 43 and troponin T genes underwent an increment of 41 and 35% in the PVDF-GO-CG compared with the PVDF-CG sample. This study proves the applicability of the PVDF-GO-CG scaffold as an alternative substrate for developing engineered cardiac tissues by providing an environment to re-establish their synchronised communications.