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Hydrogels consist of a network of highly porous polymeric chains with the potential for use as a wound dressing. Propolis is a natural product with several biological properties including anti-inflammatory, antibacterial and antioxidant activities. This study was aimed at synthesizing and characterizing a polyacrylamide/methylcellulose hydrogel containing propolis as an active ingredient, to serve as a wound dressing alternative, for the treatment of skin lesions. The hydrogels were prepared using free radical polymerization, and were characterized using scanning electron microscopy, infrared spectroscopy, thermogravimetry, differential scanning calorimetry, swelling capacity, mechanical and rheological properties, UV-Vis spectroscopy, antioxidant activity by the DPPH, ABTS and FRAP assays and biocompatibility determined in Vero cells and J774 macrophages by the MTT assay. Hydrogels showed a porous and foliaceous structure with a well-defined network, a good ability to absorb water and aqueous solutions simulating body fluids as well as desirable mechanical properties and pseudoplastic behavior. In hydrogels containing 1.0 and 2.5% propolis, the contents of total polyphenols were 24.74 ± 1.71 mg GAE/g and 32.10 ± 1.01 mg GAE/g and those of total flavonoids 8.01 ± 0.99 mg QE/g and 13.81 ± 0.71 mg QE/g, respectively, in addition to good antioxidant activity determined with all three methods used. Therefore, hydrogels containing propolis extract, may serve as a promising alternative wound dressing for the treatment of skin lesions, due to their anti-oxidant properties, low cost and availability. [ABSTRACT FROM AUTHOR]

Hydrogel is a biomaterial widely used in several areas of industry due to its great biocompatibility and adaptability to biological tissues. In Brazil, the Calendula plant is approved by the Ministry of Health as a medicinal herb. It was chosen to be incorporated in the hydrogel formulation because of its anti-inflammatory, antiseptic and healing effects. This study synthesized polyacrylamide hydrogel containing calendula extract and evaluated its efficiency as a bandage for wound healing. The hydrogels were prepared using free radical polymerization and characterized by Scanning Electron Microscopy, swelling analysis and mechanical properties by texturometer. The morphology of the matrices showed large pores and foliaceous structure. In vivo testing, as well as the evaluation of acute dermal toxicity, was conducted using male Wistar rats. The tests indicated efficient collagen fiber production, improved skin repair and no signs of dermal toxicity. Thus, the hydrogel presents compatible properties for the controlled release of calendula extract used as a bandage to promote cicatrization. [ABSTRACT FROM AUTHOR]

Chronic wounds are severe breaks in the skin barrier that fail to heal in an acceptable time-frame, thus preventing the complete restoration of the tissue's anatomical and functional integrity, increasing the likelihood of infections and apoptosis. Hydrogels are known as a drug delivery system and have the potential to cover wounds and burns on the skin. Aloe barbadensis contains over 75 different bioactive compounds which are responsible for its anti-inflammatory and antimicrobial properties. In this study, the polyacrylamide-co-methylcellulose hydrogel containing Aloe barbadensis were developed. The extract was prepared from lyophilized Aloe barbadensis, using methanolic extraction, characterized by high performance liquid chromatography and incorporated into the hydrogels. These Aloe barbadensis hydrogels were characterized by degree of swelling, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermal profiling using thermogravimetric analysis. The minimum inhibitory concentration test was done on the Aloe barbadensis extract to evaluate its antibacterial and antifungal activity in vitro. The Aloe barbadensis hydrogels and were shown to swell to almost 2000% of their original sizes. The Fourier-transform infrared spectroscopy indicated the presence of bands characteristic of Aloe barbadensis and hydrogel polymers. The basic hydrogel showed greater thermal stability than the hydrogels with Aloe barbadensis. The minimum inhibitory concentration showed inhibition of the growth of S. aureus and Salmonella spp. at specific concentrations. The hydrogel therefore presents itself as an excellent potential curative cover of cutaneous lesions. [ABSTRACT FROM AUTHOR]

Hydrogels are three-dimensional hydrophilic polymeric networks, capable of absorbing large quantities of water and biological fluids and simulating biological tissue when swollen. Hydrogels are frequently explored for use in numerous biological and biomedical applications due to their desirable properties. Hydrogels are characterized as either synthetic, natural or hybrid, based on the nature of their constituent polymers. The use of natural polymers in hydrogels for biomedical applications is advantageous due to their biocompatibility, biodegradability and non-toxicity, whereas, synthetic polymers are hydrophobic, possessing strong covalent bonds within their matrix, which improves the mechanical strength, service life and absorbability of the gels. Their polymeric crosslinking structure defines their physical or chemical nature, while their polymeric composition indicates whether they are homopolymeric, copolymeric or multipolymeric. All the classifying properties of hydrogels affect their applicability and types of areas in which they can be incorporated. In this review, we critically detail the most common natural and synthetic hydrogel formulations, their designs and their most significant and current biomedical applications. [ABSTRACT FROM AUTHOR]