Wound Dressing Applications Research Articles

Electrically Triggered Drug Delivery from Novel Electrospun Poly(Lactic Acid)/Graphene Oxide/Quercetin Fibrous Scaffolds for Wound Dressing Applications.

The novel controlled and localized delivery of drug molecules to target tissues using an external electric stimulus makes electro-responsive drug delivery systems both feasible and desirable, as well as entailing a reduction in the side effects. Novel micro-scaffold matrices were designed based on poly(lactic acid) (PLA) and graphene oxide (GO) via electrospinning. Quercetin (Q), a natural flavonoid, was loaded into the fiber matrices in order to investigate the potential as a model drug for wound dressing applications. The physico-chemical properties, electrical triggering capacity, antimicrobial assay and biocompatibility were also investigated. The newly fabricated PLA/GO/Q scaffolds showed uniform and smooth surface morphologies, without any beads, and with diameters ranging from 1107 nm (10%PLA/0.1GO/Q) to 1243 nm (10%PLA). The in vitro release tests of Q from the scaffolds showed that Q can be released much faster (up to 8640 times) when an appropriate electric field is applied compared to traditional drug-release approaches. For instance, 10 s of electric stimulation is enough to ensure the full delivery of the loaded Q from the 10%PLA/1%GO/Q microfiber scaffold at both 10 Hz and at 50 Hz. The antimicrobial tests showed the inhibition of bacterial film growth. Certainly, these materials could be loaded with more potent agents for anti-cancer, anti-infection, and anti-osteoporotic therapies. The L929 fibroblast cells cultured on these scaffolds were distributed homogeneously on the scaffolds, and the highest viability value of 82.3% was obtained for the 10%PLA/0.5%GO/Q microfiber scaffold. Moreover, the addition of Q in the PLA/GO matrix stimulated the production of IL-6 at 24 h, which could be linked to an acute inflammatory response in the exposed fibroblast cells, as a potential effect of wound healing. As a general conclusion, these results demonstrate the possibility of developing graphene oxide-based supports for the electrically triggered delivery of biological active agents, with the delivery rate being externally controlled in order to ensure personalized release.

Self-healing nanocomposite hydrogels via Janus nanosheets: Multiple effects of metal–coordination and host–guest interactions

Recently years, hydrogels have received increased attention due to their promising applications in wound dressing, tissue engineering, biosensors and human-machine interfaces. However, designing hydrogels with good mechanical strength and self-healing ability remains a challenge. As a novel strategy, functional Janus nanosheets (JNs) were used as reinforcement to develop self-healing nanocomposite hydrogels. Herein, the silica Janus hollow spheres were prepared by a sol-gel process, modified with poly(2-(acryloyloxy)ethyl ferrocenecarboxylate)(PMAEFc)/polydopamine(PDA) to the internal/external surfaces and then crushed to fabricate the SiO2@PMAEFc/PDA JNs. The SiO2@PMAEFc/PDA JNs were then used as robust reinforcement to design self-healing nanocomposite hydrogels. Based on multiple effects of metal–coordination and host–guest interactions, the mechanical strengths and self-healing properties of hydrogels were both enhanced. Specially, after introducing JNs, the rupture stress of hydrogels increased from 1.27 MPa to 2.23 MPa, and the self-healing efficiency improved from 66.7% to 92.4%. These results demonstrate that JNs can be used as robust reinforcement to fabricate self-healing nanocomposite hydrogels, which enriches the design of self-healing hydrogels and broadens the application prospects of Janus nanomaterials.

Biopolymer and Synthetic Polymer-Based Nanocomposites in Wound Dressing Applications: A Review.

Biopolymers are materials obtained from a natural origin, such as plants, animals, microorganisms, or other living beings; they are flexible, elastic, or fibrous materials. Polysaccharides and proteins are some of the natural polymers that are widely used in wound dressing applications. In this review paper, we will provide an overview of biopolymers and synthetic polymer-based nanocomposites, which have promising applications in the biomedical research field, such as wound dressings, wound healing, tissue engineering, drug delivery, and medical implants. Since these polymers have intrinsic biocompatibility, low immunogenicity, non-toxicity, and biodegradable properties, they can be used for various clinical applications. The significant advancements in materials research, drug development, nanotechnology, and biotechnology have laid the foundation for changing the biopolymeric structural and functional properties. The properties of biopolymer and synthetic polymers were modified by blending them with nanoparticles, so that these materials can be used as a wound dressing application. Recent wound care issues, such as tissue repairs, scarless healing, and lost tissue integrity, can be treated with blended polymers. Currently, researchers are focusing on metal/metal oxide nanomaterials such as zinc oxide (ZnO), cerium oxide (CeO2), silver (Ag), titanium oxide (TiO2), iron oxide (Fe2O3), and other materials (graphene and carbon nanotubes (CNT)). These materials have good antimicrobial properties, as well as action as antibacterial agents. Due to the highly antimicrobial properties of the metal/metal oxide materials, they can be used for wound dressing applications.

Fabrication and Antimicrobial Activity of Poly(lactic acid) Nanofibers Containing Firstly Synthesized Silver Diclofenac Complex with (2-methylimidazole) for Wound Dressing Applications

Fabrication and Antimicrobial Activity of Poly(lactic acid) Nanofibers Containing Firstly Synthesized Silver Diclofenac Complex with (2-methylimidazole) for Wound Dressing Applications

Characterization and evaluation of Bletilla striata polysaccharide/ethanol extract composite multifunctional sponges

Development of a fully functional dressing that can be applied throughout wound healing remains challenging. In this study, Bletilla striata polysaccharide (BSP) and the ethanol extract of B. striata (EEB) were physically blended and vacuum freeze-dried into a new medical dressing with various functions, such as hemostasis, anti-inflammatory, antibacterial and wound healing promotion. The in vivo and in vitro blood coagulation evaluation results showed that the most obvious hemostasis effects coming from the EEB25 sponge was probably due to good water absorption capacity. The drug sensitivity test results showed that the sponges presented a good antibacterial effect originated from the addition of EEB. In addition, the EEB25 sponge showed significant anti-inflammatory effects, as well as excellent biodegradability and biocompatibility. The full-thickness wound experiment illustrated the wound healing rates of EEB25 group on the 8th day and 16th day was 82.76 ± 2.78% and 95.36 ± 3.72%, respectively, which showed significant differences (p < 0.05) in comparison to the model group. Histological observations showed that the EEB25 group formed dense collagen fibers, granulation tissue and numerous new blood vessels on the 16th day, with the skin basically cured. Therefore, BSP/EEB multifunctional composite sponge provided a new perspective for the safe application of wound dressings.

Antimicrobial hydroxyapatite reinforced-polyelectrolyte complex nanofibers with long-term controlled release activity for potential wound dressing application

The prevention of wound infection has remained to be a critical step for facilitating wound healing following the application of wound dressing. To overcome such challenge, nano-hydroxyapatite (n-HAP) with high specific surface area, excellent biocompatibility, high mechanical strength and strong adsorption capacity was developed into a novel controlled release system for antimicrobial therapy. In general, n-HAP was loaded with a model antibiotic, tetracycline hydrochloride and was subsequently encapsulated inside chitosan/gelatin polyelectrolyte complex (PEC) nanofibers with a typical core-shell geometry. Firstly, the encapsulation of either tetracycline hydrochloride (TCH) or n-HAP led to the slight shrinkage of fiber diameter and enhancement in the thermotropic stability of PEC nanofiber. Secondly, the good water retention and air transmission properties of PEC was not impaired by the inclusion of n-HAP and TCH. Finally, the n-HAP reinforced PEC nanofiber membrane with encapsulated tetracycline hydrochloride has achieved the effect of long-term drug release, thereby improving the antibacterial efficacy against S. aureus, a common pathogen. Based on the good water retention, high rigidity, long term sustained drug release and prolonged antibacterial therapeutic efficacy, n-HAP reinforced PEC nanofiber membranes will serve as a promising platform for developing into novel antimicrobial wound dressings.

Polylactide/Polyvinylalcohol-Based Porous Bioscaffold Loaded with Gentamicin for Wound Dressing Applications.

This study explores the feasibility of modifying the surface liquid spraying method to prepare porous bioscaffolds intended for wound dressing applications. For this purpose, gentamicin sulfate was loaded into polylactide-polyvinyl alcohol bioscaffolds as a highly soluble (hygroscopic) model drug for in vitro release study. Moreover, the influence of inorganic salts including NaCl (10 g/L) and KMnO4 (0.4 mg/L), and post-thermal treatment (T) (80 °C for 2 min) on the properties of the bioscaffolds were studied. The bioscaffolds were characterized by scanning electron microscopy, Fourier Transform infrared spectroscopy, and differential scanning calorimetry. In addition, other properties including porosity, swelling degree, water vapor transmission rate, entrapment efficiency, and the release of gentamicin sulfate were investigated. Results showed that high concentrations of NaCl (10 g/L) in the aqueous phase led to an increase of around 68% in the initial burst release due to the increase in porosity. In fact, porosity increased from 68.1 ± 1.2 to 94.1 ± 1.5. Moreover, the thermal treatment of the Polylactide-polyvinyl alcohol/NaCl (PLA-PVA/NaCl) bioscaffolds above glass transition temperature (Tg) reduced the initial burst release by approximately 11% and prolonged the release of the drug. These results suggest that thermal treatment of polymer above Tg can be an efficient approach for a sustained release.

Influence of replacing oregano essential oil by ground oregano leaves on chitosan/alginate-based dressings properties

Biopolymers, as chitosan and alginate, have gained prominence in the biomedical area, mainly for application in wound dressings, as partial replacements for synthetic polymers. The present work aimed to compare the influence of the antimicrobial agent incorporation form on the properties of films prepared by casting. The chitosan/alginate-based films were manufactured containing oregano essential oil (OEO) or ground oregano leaves (OR). The OEO was chosen due to its excellent pharmacological properties, and the substitution by OR can represent an advantageous alternative for minimizing the final cost of the product, by removing the oil extraction step. The films, with different amounts of OEO and OR, were characterized in terms of their morphological, physicochemical, mechanical and antimicrobial properties. The films had properties according to desirable for wound dressing application: water vapor flux less than 35 g m−2 h−1, moderate liquid absorption capacity, and similar mechanical properties to human skin. All developed films showed antimicrobial activity against the bacteria Escherichia coli and Staphylococcus aureus. Formulations containing OEO presented the largest inhibition zones, although OR showed high potential for the proposed use. These results suggest that films developed, with both OEO and ground oregano leaves, are promising for use as dressings.

Rendering Banana Plant Residues into a Potentially Commercial Byproduct by Doping Cellulose Films with Phenolic Compounds.

This study seeks to render residues from banana plants into a useful byproduct with possible applications in wound dressings and food packaging. Films based on cellulose extracted from banana plant pseudostem and doped with phenolic compounds extracted from banana plant leaves were developed. The phenolic compounds were extracted using batch solid-liquid and Soxhlet methods, with different drying temperatures and periods of time. The total phenolic content and antioxidant activity were quantified. The optimum values were obtained using a three-day period batch-solid extraction at 40 °C (791.74 ± 43.75 mg/L). SEM analysis indicates that the pseudostem (PS) films have a porous structure, as opposed to hydroxyethyl cellulose (HEC) films which presented a homogeneous and dense surface. Mechanical properties confirmed the poor robustness of PS films. By contrast HEC films manifested improved tensile strength at low levels of water activity. FTIR spectroscopy reinforced the need to improve the cellulose extraction process, the success of lignin and hemicellulose removal, and the presence of phenolic compounds. XRD, TGA and contact angle analysis showed similar results for both films, with an amorphous structure, thermal stability and hydrophilic behavior.

Cosmetic, Biomedical and Pharmaceutical Applications of Fish Gelatin/Hydrolysates

There are several reviews that separately cover different aspects of fish gelatin including its preparation, characteristics, modifications, and applications. Its packaging application in food industry is extensively covered but other applications are not covered or covered alongside with those of collagen. This review is comprehensive, specific to fish gelatin/hydrolysate and cites recent research. It covers cosmetic applications, intrinsic activities, and biomedical applications in wound dressing and wound healing, gene therapy, tissue engineering, implants, and bone substitutes. It also covers its pharmaceutical applications including manufacturing of capsules, coating of microparticles/oils, coating of tablets, stabilization of emulsions and drug delivery (microspheres, nanospheres, scaffolds, microneedles, and hydrogels). The main outcomes are that fish gelatin is immunologically safe, protects from the possibility of transmission of bovine spongiform encephalopathy and foot and mouth diseases, has an economic and environmental benefits, and may be suitable for those that practice religious-based food restrictions, i.e., people of Muslim, Jewish and Hindu faiths. It has unique rheological properties, making it more suitable for certain applications than mammalian gelatins. It can be easily modified to enhance its mechanical properties. However, extensive research is still needed to characterize gelatin hydrolysates, elucidate the Structure Activity Relationship (SAR), and formulate them into dosage forms. Additionally, expansion into cosmetic applications and drug delivery is needed.

Fabrication of Sustained Release System of Electrospun Poly(acrylic acid)/Dextran Nanofibers Using Emulsion Electrospinning as Wound Dressing Applications.

The burst release of drug is a problem associated with the use of common blending electrospinning. This problem can be avoided via fabrication of core-shell nanofibers where drug can be coated with polymer nanofibers as a shell. Moreover, there is a need to provide wound dressing with prolonged system of sustained release to accelerate the recovery of the wound. Currently, electrospun ciprofloxacin loaded poly(acrylic acid)/Dextran (Cipro@PAA/Dex) core-shell nanofibers can be prepared in green method using emulsion electrospinning. For comparison study, blend electrospun nanofibers (Cipro/PAA/Dex) was also prepared. The entrapment of drug into the polymeric material and the interaction between polymer blends were confirmed by FT-IR. Moreover, DSC was used to identify the type of interaction between polymeric chains. Field emission scanning electron microscope (FE-SEM) was used to study the nanofiber morphology and transmission electron microscope (TEM) and confocal laser scanning microscope (CLSM) were used to confirm the formation of core-shell structure. In vitro drug release profile was monitored by UV-Vis spectrophotometer and the results showed that Cipro@PAA/Dex exhibited controlled release behavior whereas Cipro/PAA/Dex showed burst release behavior. Moreover, the release mechanism is kinetically followed diffusion.

Surface Modification of Electrospun Polyethylenimine/Polyvinyl Alcohol Nanofibers Immobilized with Silver Nanoparticles for Potential Antibacterial Applications

Objective: In order to investigate the potential biomedical applications of silver nanoparticle (Ag NP)-immobilized electrospun nanofibers with different surface functionalities. Methods: Silver nanoparticles were immobilized within water-stable electrospun polyethylenimine (PEI)/polyvinyl alcohol (PVA) nanofibers by an in-situ reduction method after complexing Ag+. ions with the free PEI amine groups. The obtained Ag NP-incorporated PEI/PVA nanofibers were then hydroxylated, carboxylated, and acetylated to generate different surface functionalities. Different techniques were employed to characterize the Ag NP-containing nanofibers with different surface functionalities.&gt; Results: In vitro antibacterial activity tests show that Ag NP-containing nanofibrous mats have high antibacterial activity and are capable of inhibiting the growth of both S. aureus and E. coli bacteria. Cell viability assay data show that the Ag NP-containing nanofibers are cytocompatible, and those treated by hydroxylation and acetylation display better cytocompatibility than those treated by carboxylation and the pristine non-modified fibers to promote cell adhesion and proliferation. Conclusion: Therefore, the hydroxylated or acetylated Ag NP-containing PEI/PVA nanofibers have a great potential for wound dressing, biological protection and tissue engineering applications.

Silver Nanoparticle-Based Nanocomposites for Combating Infectious Pathogens: Recent Advances and Future Prospects.

Silver nanoparticles (Ag NPs) and their nanocomposites with polymers are potent agents for antibacterial and disinfectant applications. The structural parameters of Ag-NPs, such as size, shape, and surface area, are very critical for developing appropriate formulations for the targeted applications. The impact of these factors on the performance of Ag NPs is analyzed. Ag NPs with a broad spectrum of antibacterial activities have already found applications in wound and burn dressing, food preservation, agricultural ponds, treatment for infected areas, coatings, water treatment, and other biomedical applications. Ag NPs are quite useful against antibiotic-resistant bacteria, but their level of toxicity needs careful investigation as their toxicity could be very harmful to human health and the environment. This review discusses the challenges and prospects of various Ag NPs and their composites. The review will enrich the knowledge about the efficiency and mechanism of various Ag nanoparticle-based antibacterial agents.

Preparation and characterization of injectable self-antibacterial gelatin/carrageenan/bacterial cellulose hydrogel scaffolds for wound healing application

This study reports the preparation of self-crosslinked Schiff base gels using gelatin and oxidized carrageenan gum interpenetrated with bacterial cellulose (BC) as injectable drug delivery systems. The injectable gels were successfully prepared at body temperature upon blending with BC and loaded with bovine serum albumin (as the model drug) to produce scaffolds. The gel scaffolds were characterized via rheological, FTIR, SEM, XRD, TGA and mechanical compression analysis. Gelation kinetics of gels as well as swelling, in vitro degradation and drug release kinetics of gel scaffolds were examined. Results showed that the incorporation of BC to the gel system considerably improved mechanical integrity with remarkable rheological shear-thinning properties. Maximum in vitro cumulative drug release from gel scaffolds was determined as 84.01 ± 3.66% within the studied time interval of 168 h. Further analysis showed that the prepared gel scaffolds possess self-antibacterial properties with growth inhibition capacity against E. coli, S. aureus, and K. pneumonia. In vitro cell cytotoxicity was also performed by MTT assay and results depicted >80% cell viability, which indicates the gel scaffolds are cytocompatible. In conclusion, this paper presents a facile approach to fabricate all-natural crosslinked injectable self-antibacterial gels systems with prospective potential application in wound dressing and tissue regeneration.

Novel multifunctional adenine-modified chitosan dressings for promoting wound healing

Wound healing is a dynamic and intricate process, and newly dressings are urgently needed to promote wound healing over the multiple stages. Herein, two water-soluble adenine-modified chitosan (CS-A) derivatives were synthesized in aqueous solutions and freeze-dried to obtain porous sponge-like dressings. The novel derivatives displayed antibacterial activities against S. aureus and E. coli. Moreover, CS-A derivatives demonstrated excellent hemocompatibility and cytocompatibility, as well as promoted the proliferation of the wound cells by shortening the G1 phase and improving DNA duplication efficiency. The ability of CS-A sponges to promote wound healing was studied in a full-thickness skin defect model. The histological analysis and immunohistochemical staining showed that the wounds treated with CS-A sponges displayed fewer inflammatory cells, and faster regeneration of epithelial tissue, collagen deposition and neovascularization. Therefore, CS-A derivatives have potential application in wound dressings and provide new ideas for the design of multifunctional biomaterials.

Celluloses as support materials for antibacterial agents: a review

The fabrication of safe, low cost and stable biocompatible antibacterial materials suitable for application in wound dressing and health sectors has been the main challenge for the researchers during the last 20 years. It has been demonstrated that naturally abundant cellulose bearing numerous readily modifiable hydroxyl groups along the chain can be good support materials for fixing antibacterial agents of both inorganic and organic origin. Additionally, strong tensile strength, biocompatible nature and favorable for application in moist environment are other suitable properties of cellulose that favor targeted transferring of immobilized antibacterial agents. However, special attention and emphasis are to be given during preparation so that the antibacterial agents supported on cellulose retain their antibacterial properties for mid to long-term application, and requisite application properties such as proper biocompatibility, strong fixation of antibacterial agents preventing leaching/leakage, color fastness, mechanical properties etc. are maintained. So far, various routes have been proposed for the preparation of cellulose based antibacterial biocomposites. Much attention has also been paid to measure the antibacterial activity but other aspects, mentioned above, are either not discussed or improperly resolved. In this review, attempt is made to find out merits and demerits in terms of performance stability, processing simplicity, cytotoxicity and efficiency in antibacterial activity, and propose new ideas for preparing more durable and efficient biocompatible antibacterial cellulose biocomposites to meet rising demand for more versatile applications.

Fabrication of PVA/PAAm IPN hydrogel with high adhesion and enhanced mechanical properties for body sensors and antibacterial activity

PVA hydrogel has excellent adhesion ability and biocompatibility, and is considered as a promising material in the field of wound dressings. However, the traditional PVA hydrogel has poor mechanical properties, which greatly limits its application. In this article, we obtained a PVA/PAAm interpenetrating networks (IPN) hydrogel by a one-pot free radical polymerization method, which improved the mechanical strength and retained the original properties of the PVA. The IPN hydrogel was proved to possess excellent adhesion strength and rheological properties with certain conductivity, which can be used as a human motion monitor. To achieve the application of wound dressing, a polymer antibacterial agent of polyhexamethylene guanidine (PHMG) was introduced into the hydrogel. The results showed the antibacterial properties of the PVA/PAAm IPN hydrogel were enhanced obviously on both Gram-positive and Gram-negative bacteria. The prepared PVA/PAAm IPN hydrogel may provide the possibility for the application in the field of body sensors and wound dressing.

A nature-derived, flexible and three dimensional (3D) nano-composite for chronic wounds pH monitoring

Current technologies on conductive carbon aerogels are merely for application of super-capacitors, anodes of lithium ion batteries and electrocatalysts. To our best knowledge, carbon nanofibre (CNF) aerogels in biomedical application of chronic wound monitoring have not been reported yet. In this paper, we proposed a chronic wounds pH sensor, which is based on 3D free-standing conductive CNF aerogel derived from pyrolyzed bacterial cellulose (p-BC) as conducting substrate and it is incorporated with flexible and proton-selective PDMS/PANI composite. The resulted p-BC/PDMS/PANI nanocomposite is soft, flexible, and can exhibit near Nernst limit pH sensitivity (~−50.4 mV/pH) in pH buffer solution, and −29 mV/pH in in vitro simulated wound fluid. This renders its applications in flexible bio-sensors and smart wound dressings.

Bacterial nanocellulose production and biomedical applications.

Bacterial nanocellulose (BNC) is a homopolymer of β-1,4 linked glycose, which is synthesized by Acetobacter using simple culturing methods to allow inexpensive and environmentally friendly small- and large-scale production. Depending on the growth media and types of fermentation methods, ultra-pure cellulose can be obtained with different physio-chemical characteristics. Upon biosynthesis, bacterial cellulose is assembled in the medium into a nanostructured network of glucan polymers that are semitransparent, mechanically highly resistant, but soft and elastic, and with a high capacity to store water and exchange gasses. BNC, generally recognized as safe as well as one of the most biocompatible materials, has been found numerous medical applications in wound dressing, drug delivery systems, and implants of heart valves, blood vessels, tympanic membranes, bones, teeth, cartilages, cornea, and urinary tracts.

Study of the Antibacterial Property of Tea Tree Oil and Its Incorporation Into Poly(Lactic Acid)‐montmorillonite Clay Bionanocomposites

AbstractThe presence of microorganisms in skin wounds can lead to infections that hamper the healing process; therefore, growing interest is given to the development of antimicrobial dressing. This study evaluates the ability of tea tree essential oil (EO) to eliminate resistant microorganisms, and new antibacterial bionanocomposites are prepared in two steps, namely sonication followed by melt mixing. Montmorillonite clay (MMT) and poly(acid lactic) (PLA) are chosen for constituting a polymer‐clay bionanocomposite for application in wound dressing. MMT retains and promotes a controlled release of the drug into the wound. Synthetic PLA is approved by the Food and Drug Administration for wound dressing applications. Disk diffusion tests evaluate the antimicrobial properties of tea tree oil, and X‐ray diffraction (XRD) and transmission electron microscopy (TEM) analyzed the extent of clay intercalation/exfoliation. Tea tree essential oil is effective against Escherichia coli and Staphylococcus aureus bacteria. According to the XRD results, the preparation method used can promote oil incorporation into the MMT galleries. TEM micrographs corroborated such results showing the coexistence of intercalated‐exfoliated structures in the bionanocomposites. As a conclusion, the produced bionanocomposites with tea tree essential oil are interesting antibacterial material to be used in wound dressing applications.