Preparation Method of Porous Dressing Materials Based on Butyric-Acetic Chitin Co-Polyesters

Methyl cellulose/okra mucilage composite films, functionalized with Hypericum perforatum oil and gentamicin, as a potential wound dressing

There is a growing demand for the development of functional wound dressings enriched with bioactive natural compounds to improve the quality of life of the population by accelerating the healing process of chronic wounds. In this regard, a functional composite film of okra mucilage (OM) and methylcellulose (MC) incorporated with Hypericum perforatum oil (Hp) and gentamicin (G) was prepared and characterized as a wound dressing. Increasing Hp resulted in improved film properties with a more porous structure, higher WVTR, and lower surface hydrophobicity. Furthermore, incorporating Hp into OM:MC films led to increased elongation at the break while reducing the tensile strength of the films. The highest values of total antioxidant capacity (1.09-1.16 mM trolox equivalent) and total phenolic content (13.76-16.94 μg GA equivalent mL-1) were measured in the composite films containing the highest Hp concentration (1.5 %). In addition, OM:MC/HpG composite films exhibited significant antibacterial activity against both E. coli and S. aureus and prevented the transmission of these bacteria through the films. Hp incorporation reduced the cytotoxic effects of OM:MC films on BJ cells and increased the wound closure rate in vitro. In conclusion, the developed OM:MC/HpG composite film can be a promising candidate as a novel wound dressing with its superior properties.

Natural Polymer-Based Thin Film Strategies for Skin Regeneration in Lieu of Regenerative Dentistry

Wound healing (WH) is a complex and dynamic process that comprises of a series of molecular and cellular events that occur after tissue injury. The injuries of the maxillofacial and oral region caused by trauma or surgery result in undesirable WH such as delayed wound closure and formation of scar tissue. Skin tissue engineering (TE)/regeneration is an emerging approach toward faster, superior, and more effective resolution of clinically significant wounds effectively. A multitude of TE principles approaches are being put to action for the fabrication of hydrogels, electrospun sheets, 3D scaffolds, and thin films that can be used as wound dressings materials, sutures, or skin substitutes. Thin films are advantageous over other materials owing to their flexibility, ability to provide a barrier against external contamination, easy gaseous exchange, and easy monitoring of wounds. This review focuses on wound-dressing films and their significance and discusses various fabrication techniques. In addition, we explore various natural biopolymers that can be used for fabrication of skin TE materials. Impact Statement In this review article, critical evaluations of natural polymers used in skin regeneration were discussed. Further, the fabrication technology of the 2D and 3D material in wound healing were discussed.

Effect of cold plasma treatment on polylactic acid and polylactic acid/poly (ethylene glycol) films developed as a drug delivery system for streptomycin sulfate

Polylactic acid (PLA) being a renewable polyester have extensively researched in the biomedical field due to its non-toxicity, high biocompatibility, and easy processing properties. However, low functionalization ability and hydrophobicity limit its applications and hence demands physical and chemical modifications to overcome these limitations. Cold plasma treatment (CPT) is frequently used to improve the hydrophilic properties of PLA-based biomaterials. This provides an advantage to obtain a controlled drug release profile in drug delivery systems. The rapid drug release profile may be advantageous in some applications such as wound application. The main objective of this study is to determine the effects of CPT on PLA or PLA@polyethylene glycol (PLA@PEG) porous films fabricated by solution casting method for use as a drug delivery system with a rapid release profile. The physical, chemical, morphological and drug release properties of PLA and PLA@PEG films, such as surface topography, thickness, porosity, water contact angle (WCA), chemical structure, and streptomycin sulfate release properties, after CPT were systematically investigated. XRD, XPS and FTIR results showed that oxygen-containing functional groups were formed on the film surface with CPT without changing the bulk properties. Along with the changes in the surface morphology such as surface roughness and porosity, the new functional groups provide the films hydrophilic properties by reducing the water contact angle. The improved surface properties enabled the selected model drug, streptomycin sulfate, to exhibit a faster release profile with drug-released mechanism fitted by first order kinetic model. Considering all the results, the prepared films showed an enormous potential for future drug delivery applications, especially in wound application where rapid drug release profile is an advantage.

The Influence of Novel, Biocompatible, and Bioresorbable Poly(3-hydroxyoctanoate) Dressings on Wound Healing in Mice

The human body's natural protective barrier, the skin, is exposed daily to minor or major mechanical trauma, which can compromise its integrity. Therefore, the search for new dressing materials that can offer new functionalisation is fully justified. In this work, the development of two new types of dressings based on poly(3-hydroxyoctanoate) (P(3HO)) is presented. One of the groups was supplemented with conjugates of an anti-inflammatory substance (diclofenac) that was covalently linked to oligomers of hydroxycarboxylic acids (Oli-dicP(3HO)). The novel dressings were prepared using the solvent casting/particulate leaching technique. To our knowledge, this is the first paper in which P(3HO)-based dressings were used in mice wound treatment. The results of our research confirm that dressings based on P(3HO) are safe, do not induce an inflammatory response, reduce the expression of pro-inflammatory cytokines, provide adequate wound moisture, support angiogenesis, and, thanks to their hydrophobic characteristics, provide an ideal protective barrier. Newly designed dressings containing Oli-dicP(3HO) can promote tissue regeneration by partially reducing the inflammation at the injury site. To conclude, the presented materials might be potential candidates as excellent dressings for wound treatment.

Evaluation of Polysaccharide-Peptide Conjugates Containing the RGD Motif for Potential Use in Muscle Tissue Regeneration

New scaffold materials composed of biodegradable components are of great interest in regenerative medicine. These materials should be: stable, nontoxic, and biodegrade slowly and steadily, allowing the stable release of biodegradable and biologically active substances. We analyzed peptide-polysaccharide conjugates derived from peptides containing RGD motif (H-RGDS-OH (1), H-GRGDS-NH₂ (2), and cyclo(RGDfC) (3)) and polysaccharides as scaffolds to select the most appropriate biomaterials for application in regenerative medicine. Based on the results of MTT and Ki-67 assays, we can state that the conjugates containing calcium alginate and the ternary nonwoven material were the most supportive of muscle tissue regeneration. Scanning electron microscopy imaging and light microscopy studies with hematoxylin-eosin staining showed that C2C12 cells were able to interact with the tested peptide-polysaccharide conjugates. The release factor (Q) varied depending on both the peptide and the structure of the polysaccharide matrix. LDH, Alamarblue^®, Ki-67, and cell cycle assays indicated that peptides 1 and 2 were characterized by the best biological properties. Conjugates containing chitosan and the ternary polysaccharide nonwoven with peptide 1 exhibited very high antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae. Overall, the results of the study suggested that polysaccharide conjugates with peptides 1 and 2 can be potentially used in regenerative medicine.

Characteristic Features of Wound Dressings Based on Butyric-Acetic Chitin Copolyesters-Results of Clinical Trials

The article presents the results of clinical trials of wound dressings whose main ingredient is butyric-acetic chitin copolyester (BAC 90:10). It is a chitin derivative soluble in typical organic solvents. During the trial, the dressings were used on wounds resulting from venous insufficiency or diabetes. The trial evaluated the safety of use and efficacy of three forms of the dressing including porous membrane (Medisorb R Membrane), porous membrane with silver (Medisorb R Ag), and powder (Medisorb R Powder). The clinical trial had a multi-centre character. Three medical units were engaged in the study. The trial included 36 patients (12 men and 24 women). The mean age of the participants was 65 years of age (age range: 26-96). The choice of dressings was made on the basis of preliminary evaluation of the wound, clinical signs of infection, or risk of infection. Medisorb R Membrane dressing was used in 23 patients, Medisorb R Ag dressing was used in 15 patients, and Medisorb R powder was used in two patients. During the course of the trial, there were 10 control visits planned. The obtained results prove the safety and efficacy of dressings in question. The efficacy of treatment was evaluated as good. In the majority of patients, the ulceration was decreased both on the surface and in depth. The success of the treatment relied not only on the applied dressing, but also the stage of the basic disease, the accompanying diseases, and the age of the patient.

Influence of Porous Dressings Based on Butyric-Acetic Chitin Co-Polymer on Biological Processes In Vitro and In Vivo

In spite of intensively conducted research allowing for the development of more and more advanced wound dressing materials, there is still a need for dressings that stimulate not only reparative and regenerative processes, but also have a positive effect on infected and/or difficult-to-heal wounds. Porous dressing materials based on butyric-acetic chitin co-polyester containing 90% of butyryl and 10% of acetyl groups (BAC 90/10) can also be included in the group mentioned above. Two types of dressings were obtained by the salt leaching method, i.e. a porous sponge Medisorb R and Medisorb Ag with an antibacterial additive. The aim of the study was to evaluate biological effects of porous Medisorb R and Medisorb Ag dressings under in vitro and in vivo conditions. In an in vitro biodegradation test, no mass loss of Medisorb R dressing was observed within 14 days of incubation in physiological fluids at 37 °C. However, on the basis of the FTIR (Fourier Transform Infrared Spectroscopy) tests, surface degradation of Medisorb R dressing was observed. Additionally, the antibacterial activity of the porous Medisorb Ag dressing containing microsilver as an antibacterial additive was confirmed. The in vivo studies included inflammatory activity, skin irritation and sensitisation tests, as well an assessment of local effect after contact with subcutaneous tissue up to 6 months and skin wounds up to 21 days. In the in vivo tests, the dressings exhibited neither effects of skin irritation nor sensitisation. Under macroscopic examination, in full thickness defects of subcutaneous tissue and skin, the dressings caused wound healing with no inflammation, undergoing the most gradual biodegradation between weeks 4 and 8, and the observed differences were statistically significant. In the histological assessment, a weakened, limited inflammatory process associated with degradation of the material has been observed. The process of skin wound healing under Medisorb R dressing in the early period was accelerated compared to that observed in the control group with a gauze dressing.