A photocrosslinkable and hemostatic bilayer wound dressing based on gelatin methacrylate hydrogel and polyvinyl alcohol foam for skin regeneration.

The enormous potential of multifunctional bilayer wound dressings in various medical interventions for wound healing has led to decades of exploration into this field of medicine. However, it is usually difficult to synthesize a single hydrogel with all the required capabilities simultaneously. This paper proposes a bilayer model with an outer layer intended for hydrogel wound treatment. By adding gelatin methacrylate (GelMA) and tannic acid (TA) to the hydrogel composition and using polyvinyl alcohol-carboxymethyl chitosan (PVA-CMCs) foam layer as supports, a photocrosslinkable hydrogel with an optimal formulation was created. The hydrogels were then examined using a range of analytical procedures, including mechanical testing, rheology, chemical characterization, and in vitro and in vivo tests. The resulting bilayer wound dressing has many desirable properties, namely uniform adhesion and quick crosslinking by UV light. When used against Gram-positive and Gram-negative bacterial strains, bilayer wound dressings demonstrated broad antibacterial efficacy. In bilayer wound dressings with GelMA and TA, better wound healing was observed. Those without these elements showed less effectiveness in healing wounds. Additionally, encouraging collagen production and reducing wound infection has a major therapeutic impact on wounds. The results of this study could have a significant impact on the development of better-performing wound dressings.

Antibacterial self-healing bilayer dressing for epidermal sensors and accelerate wound repair.

This study aimed to investigate the effect of the bilayer hydrogel as a wound dressing on the wound-healing rate. We synthesized a self-healing hydrogel with optimized formulation by introducing natural polymer (chitosan) and arginine to the hydrogel composition. We then characterized the hydrogels using FT-IR, thermal analysis, mechanical testing, and in vitro and in vivo assay. The resulting bilayer wound dressing offers a lot of desirable characteristics, including good self-healing and repeatable adhesiveness. Likewise, the conductive bilayer wound dressing could be used to analyze the patient's healthcare data in real-time as epidermal sensors. Bilayer wound dressings remarkably have broad antibacterial efficacy against Gram-positive and Gram-negative bacteria. The potential applications of this bilayer wound dressing are illustrated by detectable body movement and conductivity. The wound-healing rate of bilayer wound dressings containing chitosan and arginine was higher, but those without the aforementioned ingredients had lower wound-healing efficacy. Additionally, promoting collagen synthesis and reducing wound infection has a considerable therapeutic impact on wounds. These results could have significant implications for the development of high-performance wound dressings.

Antimicrobial activity and wound healing effect of a novel natural ointment: an in vitro and in vivo study.

Infection and pathological disorders, such as cellular disorders, ischaemia, neuropathy and angiogenesis, are considered the most critical factors which cause a delay in the wound healing process in patients with diabetes. This study aimed to investigate the effect of an ointment based on ostrich oil containing honey, beeswax, and ethanolic extracts of Nigella sativa, propolis and Cassia angustifolia on the wound healing process of diabetic rats. Gas chromatography/mass spectrometry analysis showed caffeic acid and pinostrobin chalcone molecules present in propolis, giving antibacterial and antifungal properties to the compound. The antibacterial assessment showed the ointment had remarkable antibacterial activity against Staphylococcus aureus (8.6±0.28mm), Escherichia coli (9.4±0.31mm), Acinetobacter baumannii (7.2±0.23mm) and Pseudomonas aeruginosa (13.9±0.42mm). In vivo results showed the ointment significantly accelerated wound healing and increased collagen deposition compared with the control (p<0.05). Histopathology evaluation also showed hair follicles, sebaceous glands and vessels in the group that used the ointment. These results proved successful and diabetic wound healing was rapid. Therefore, it could be concluded that the fabricated ointment could be a suitable candidate for wound healing.

A Novel Bilayer Wound Dressing Composed of a Dense Polyurethane/Propolis Membrane and a Biodegradable Polycaprolactone/Gelatin Nanofibrous Scaffold.

One-layer wound dressings cannot meet all the clinical needs due to their individual characteristics and shortcomings. Therefore, bilayer wound dressings which are composed of two layers with different properties have gained lots of attention. In the present study, polycaprolactone/gelatin (PCL/Gel) scaffold was electrospun on a dense membrane composed of polyurethane and ethanolic extract of propolis (PU/EEP). The PU/EEP membrane was used as the top layer to protect the wound area from external contamination and dehydration, while the PCL/Gel scaffold was used as the sublayer to facilitate cells' adhesion and proliferation. The bilayer wound dressing was investigated regarding its microstructure, mechanical properties, surface wettability, anti-bacterial activity, biodegradability, biocompatibility, and its efficacy in the animal wound model and histopathological analyzes. Scanning electron micrographs exhibited uniform morphology and bead-free structure of the PCL/Gel scaffold with average fibers' diameter of 237.3 ± 65.1 nm. Significant anti-bacterial activity was observed against Staphylococcal aureus (5.4 ± 0.3 mm), Escherichia coli (1.9 ± 0.4 mm) and Staphylococcus epidermidis (1.0 ± 0.2 mm) according to inhibition zone test. The bilayer wound dressing exhibited high hydrophilicity (51.1 ± 4.9°), biodegradability, and biocompatibility. The bilayer wound dressing could significantly accelerate the wound closure and collagen deposition in the Wistar rats' skin wound model. Taking together, the PU/EEP-PCL/Gel bilayer wound dressing can be a potential candidate for biomedical applications due to remarkable mechanical properties, biocompatibility, antibacterial features, and wound healing activities.

A propolis enriched polyurethane-hyaluronic acid nanofibrous wound dressing with remarkable antibacterial and wound healing activities.

A biocompatible and antibacterial scaffold with efficient wound healing activity can be an appropriate option for wound dressing application. In this study, polyurethane-hyaluronic acid (PU-HA) nanofibrous wound dressing was fabricated and then enriched with three different concentrations of ethanolic extract of propolis (EEP). The obtained samples were characterized by attenuated total reflectance/Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, mechanical investigations, antibacterial tests, water uptake exam, and in vitro and in vivo evaluations. The PU-HA/1% EEP and PU-HA/2% EEP samples exhibited higher antibacterial activity against Staphylococcus aureus (2.36 ± 0.33 and 5.63 ± 0.87 mm), Escherichia coli (1.94 ± 0.12 and 3.18 ± 0.63 mm) in comparison with other samples. However, the PU-HA/1% EEP sample exhibited significantly higher biocompatibility for L929 fibroblast cells in comparison with PU-HA/2% EEP. Also, the PU-HA/1% EEP sample could significantly accelerate the wound healing progression and wound closure at the animal model. At the histopathological analyses, improved dermis development and collagen deposition at the healed wound area of the PU-HA/1% EEP sample in comparison with other groups was observed. These results indicate that 1 wt% EEP enriched PU-HA nanofibrous scaffold can be a promising candidate with considerable biocompatibility, wound healing, and antibacterial activities for further biomedical applications.

A Review of Controlled Drug Delivery Systems Based on Cells and Cell Membranes.

Novel drug delivery systems have ameliorated drugs' pharmacokinetics and declined undesired ramifications while led to a better patient compliance by extending the time of release. In fact, although there has been a multitude of encouraging achievements in controlled drug release, the application of micro- and nano-carriers is confronted with some challenges such as rapid clearance and inefficient targeting. In addition, since cell systems can be an appropriate alternative to micro- and nano-particles, they have been used as biological carriers. In general, features such as stable release into blood, slow clearance, efficient targeting, and high biocompatibility are the main properties of cells applied as drug carriers. Furthermore, some cells such as erythrocytes, leukocytes, stem cells, and platelets have been used as release systems. Hence, most common cells that were used as aforementioned release systems are going to be presented in this review article.

Cornstarch-based wound dressing incorporated with hyaluronic acid and propolis: In vitro and in vivo studies.

The unique physicochemical and functional characteristics of starch-based biomaterials and wound dressings have been proposed for several biomedical applications. Film dressings of cornstarch/hyaluronic acid/ ethanolic extract of propolis (CS/HA/EEP) were prepared by solvent-casting and characterized by attenuated total reflectance/Fourier transform infrared spectroscopy, scanning electron microscopy, gas chromatography/mass spectrometry, light transmission, opacity measurements, EEP release, equilibrium swelling, and in vitro and in vivo evaluations. The CS/HA/0.5%EEP film dressing exhibited higher antibacterial activity against Staphylococcus aureus (2.08 ± 0.14 mm), Escherichia coli (2.64 ± 0.18 mm), and Staphylococcus epidermidis (1.02 ± 0.15 mm) in comparison with the CS, CS/HA, and CS/HA/0.25%EEP films. Also, it showed no cytotoxicity for the L929 fibroblast cells. This wound dressing could effectively accelerate the wound healing process at Wistar rats' skin excisions. These results indicate that enrichment of cornstarch wound dressings with HA and EEP can significantly enhance their potential efficacy as wound dressing material.

In vitro and in vivo performance of a propolis-coated polyurethane wound dressing with high porosity and antibacterial efficacy.

Wound dressings with antimicrobial and wound healing accelerating properties are emerging as valuable options to prevent wound infection and improve the wound healing process. In this study, high porous polyurethane (PU) foams were successfully prepared using salt leaching/solvent casting method and were coated with propolis as a well-known anti-bacterial agent. The wound dressings were subjected to detail analyzes using electron microscopy, reflectance Fourier transform infrared spectroscopy, mechanical properties, contact angle measurement, ratio swelling, porosity measurement, and in vitro and in vivo evaluations. The prepared wound dressings had high porosity (more than 80%) with homogeneous pore structure and sufficient interconnectivity. The increase of propolis concentration (10%-30%) caused tensile strength decrease (5.26 ± 0.40-2.99 ± 0.11 MPa), elongation at break increase (372 ± 12-434 ± 22%), contact angle decrease (114.52 ± 2.31° to 35.53 ± 1.65°), water absorption decreased (243 ± 15-207 ± 14%) and enhancement of the antibacterial activity against Escherichia coli and Staphylococcus aureus. The propolis coated wound dressing exhibited significant enhancement of in vitro cellular compatibility and in vivo wound healing which had direct relative with coated propolis concentration. Therefore, propolis-coated polyurethane wound dressing can be an appropriate candidate for more pre-clinical investigations.