Double‐layer PLLA /PEO_Chitosan nanofibrous mats containing Hypericum perforatum L. as an effective approach for wound treatment

Electrospun wound dressings with antibacterial function: a critical review of plant extract and essential oil incorporation

Among the many different types of wound dressings, nanofiber-based materials produced through electrospinning are claimed to be ideal because of their advantageous intrinsic properties and the feasibility of employing several strategies to load bioactive compounds into their structure. Bioactive compounds with antimicrobial properties have been incorporated into different wound dressings to promote healing as well as prevent and treat bacterial infections. Among these, natural products, such as medicinal plant extracts and essential oils (EOs), have proven particularly attractive thanks to their nontoxic nature, minor side effects, desirable bioactive properties, and favorable effects on the healing process. To this end, the present review provides an exhaustive and up-to-date revision of the most prominent medicinal plant extracts and EOs with antimicrobial properties that have been incorporated into nanofiber-based wound dressings. The most common methods used for incorporating bioactive compounds into electrospun nanofibers include: pre-electrospinning (blend, encapsulation, coaxial, and emulsion electrospinning), post-electrospinning (physical adsorption, chemical immobilization, and layer-by-layer assembly), and nanoparticle loading. Furthermore, a general overview of the benefits of EOs and medicinal plant extracts is presented, describing their intrinsic properties and biotechniques for their incorporation into wound dressings. Finally, the current challenges and safety issues that need to be adequately clarified and addressed are discussed.

In vitro assessment of Momordica charantia/Hypericum perforatum oils loaded PCL/Collagen fibers: Novel scaffold for tissue engineering

The research on tissue engineering applications has been progressing to manufacture ideal tissue scaffold biomaterials. In this study, a double-layered electrospun biofiber scaffold biomaterial including Polycaprolactone (PCL)/Collagen (COL) fibrous inner layer and PCL/ Momordica charantia (MC) and Hypericum perforatum (HP) oils fibrous outer layer was developed to manufacture a functional, novel tissue scaffold with the advantageous mechanical and biological properties. The main approach was to combine the natural perspective using medicinal oils with an engineering point of view to fabricate a potential functional scaffold for tissue engineering. Medicinal plants MC and HP are rich in functional oils and incorporation of them in a tissue scaffold will unveil their potential to augment both new tissue formation and wound healing. In this study, a novel double-layered scaffold prototype was fabricated using electrospinning technique with two PCL fiber layers, first is composed of collagen, and second is composed of oils extracted from medicinal plants. Initially, the composition of plant oils was analyzed. Thereafter the biofiber scaffold layers were fabricated and were evaluated in terms of morphology, physicochemistry, thermal and mechanical features, wettability, in vitro bio-degradability. Double-layered scaffold prototype was further analyzed in terms of in vitro biocompatibility and antibacterial effect. The medicinal oils blend provided antioxidant and antibacterial properties to the novel PCL/Oils layer. The results signify that inner PCL/COL layer exhibited advanced biodegradability of 8.5% compared to PCL and enhanced wettability with 11.7° contact angle. Strength of scaffold prototype was 5.98 N/mm2 thanks to the elastic PCL fibrous matrix. The double-layered functional biofiber scaffold enabled 92% viability after 72 h contact with fibroblast cells and furthermore provided feasible attachment sites for the cells. The functional scaffold prototype's noteworthy mechanical, chemical, and biological features enable it to be suggested as a different novel biomaterial with the potential to be utilized in tissue engineering applications.

Innovative Bioactive Nanofibrous Materials Combining Medicinal and Aromatic Plant Extracts and Electrospinning Method

Since antiquity, humans have known about plants as a medicinal cure. Recently, plant extracts are attracting more attention as a result of their natural origin and wide range of desirable features. Nanotechnology's progress and innovations enable the production of novel materials with enhanced properties for a broad range of applications. Electrospinning is a cutting-edge, flexible and economical technique that allows the creation of continuous nano- and microfibrous membranes with tunable structure, characteristics and functionalities. Electrospun fibrous materials are used in drug delivery, tissue engineering, wound healing, cosmetics, food packaging, agriculture and other fields due to their useful properties such as a large surface area to volume ratio and high porosity with small pore size. By encapsulating plant extracts in a suitable polymer matrix, electrospinning can increase the medicinal potential of these extracts, thus improving their bioavailability and maintaining the required concentration of bioactive compounds at the target site. Moreover, the created hybrid fibrous materials could possess antimicrobial, antifungal, antitumor, anti-inflammatory and antioxidant properties that make the obtained structures attractive for biomedical and pharmaceutical applications. This review summarizes the known approaches that have been applied to fabricate fibrous materials loaded with diverse plant extracts by electrospinning. Some potential applications of the extract-containing micro- and nanofibers such as wound dressings, drug delivery systems, scaffolds for tissue engineering and active food packaging systems are discussed.

Enrichment of Cellulose Acetate Nanofibrous Scaffolds with Retinyl Palmitate and Clove Essential Oil for Wound Healing Applications

The use of biocompatible materials and fabrication methods is of particular importance in the development of wound dressings. Cellulose acetate (CA) has excellent properties for wound dressing applications, but it is insufficient for the wound healing process due to its lack of bioactive and antibacterial properties. In this study, CA was electrospun with retinyl palmitate (RP) and clove essential oil (CLV) to fabricate a novel antibacterial and antioxidant biomaterial. The effects of RP and CLV incorporation on the surface morphology, fiber diameter, antioxidant activity, antibacterial activity, cell viability, and release behavior of the fabricated CA mats were investigated. In light of these studies, it was determined that the nanofiber mat, fabricated with a 15% w/v CA polymer concentration, a 1% w/w RP ratio, and a 5% w/w CLV ratio, was biocompatible with L929 fibroblast cells with antibacterial and antioxidant properties. Overall, results showed that this nanofiber offers promise for use as a wound dressing.

Single unit functionally graded bioresorbable electrospun scaffold for scar-free full-thickness skin wound healing

Full-thickness wounds are difficult to heal spontaneously. Scaffolds, meant for treating full-thickness wounds, should ensure proper tissue regeneration, both structurally and functionally. An ideal scaffold should mimic the physical, mechanical and biochemical properties of natural skin. However, available mono- or bi-layer skin scaffolds lack in the precise architecture and functionality, thus, failing to provide scar-free regeneration of full-thickness skin wounds. These unmet challenges of scar-free skin regeneration have been addressed in the present study for the first time. This research deals with the synthesis of a low-cost, structurally and functionally graded single unit biodegradable polymeric scaffold. The functional gradient in this scaffold was achieved by varying polymer concentration and electrospinning parameters. This gradient in the scaffold provided the required microenvironment for proper functional and structural reconstruction of all the layers of natural skin. The mechanical property of the scaffold matched that of the natural skin. Besides, the degradation kinetics of the scaffold was in coordination with the regeneration time for the full-thickness wound. The porosity and hydrophilicity gradients of the scaffold helped it mimic the in vivo hypodermal, dermal and epidermal microenvironments of the skin, simultaneously. Co-culturing PCS-201 (dermal fibroblasts) and HaCaT (keratinocytes) on the scaffold resulted in successful regeneration through cellular proliferation, differentiation and organization of the skin tissue. The scaffold also displayed better wound healing in vivo, in terms of speedy wound closure and proper tissue regeneration, in comparison to the standard treatment. Altogether, this study successfully established a simple, one-step synthesis process of a functionally graded, bioresorbable scaffold for scar-free, native-like, structural and functional regeneration of full-thickness skin wounds. Due to cost-effectiveness, easy synthesis process and microarchitectural features, the designed scaffold possesses a potential of translation to a good commercial wound healing product.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

Electrospun hierarchical structural films for effective wound healing

Patients with acute and chronic wounds have been increasing around the world, and the demand for wound treatment and care is also increasing. Therefore, a new nanofiber wound dressing should be prepared to promote the wound healing process. In this study, we report the design and preparation of a hierarchical structural film wound dressing. The top layer is composed of profoundly hydrophobic polycaprolactone (PCL), which is used to resist the adhesion of external microorganisms. The bottom layer is made of hydrophilic gelatin, which provides a moist healing environment for the wound. The middle layer is composed of hydrophilic Janus nanofibers prepared with the latest side-by-side electrospinning technique. Gelatin and PCL are used as polymer matrices loaded with the ciprofloxacin (CIP) drug and zinc oxide nanoparticles (n-ZnO), respectively. Test results show that the dressing has outstanding surface wettability, excellent mechanical properties, and rapid drug release. The presence of biologically active ingredients provides antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Finally, the results of wound healing in mice show accelerated collagen deposition, promotion of angiogenesis, and complete wound healing within 14 days. Overall, this hierarchical structural dressing has a strong potential for accelerating wound healing.

Poly(lactic acid)-Based Electrospun Fibrous Structures for Biomedical Applications

Poly(lactic acid)(PLA) is an aliphatic polyester that can be derived from natural and renewable resources. Owing to favorable features, such as biocompatibility, biodegradability, good thermal and mechanical performance, and processability, PLA has been considered as one of the most promising biopolymers for biomedical applications. Particularly, electrospun PLA nanofibers with distinguishing characteristics, such as similarity to the extracellular matrix, large specific surface area and high porosity with small pore size and tunable mechanical properties for diverse applications, have recently given rise to advanced spillovers in the medical area. A variety of PLA-based nanofibrous structures have been explored for biomedical purposes, such as wound dressing, drug delivery systems, and tissue engineering scaffolds. This review highlights the recent advances in electrospinning of PLA-based structures for biomedical applications. It also gives a comprehensive discussion about the promising approaches suggested for optimizing the electrospun PLA nanofibrous structures towards the design of specific medical devices with appropriate physical, mechanical and biological functions.

An In Vitro Study of Antibacterial Properties of Electrospun Hypericum perforatum Oil-Loaded Poly(lactic Acid) Nonwovens for Potential Biomedical Applications

The growth of population and increase in diseases that cause an enormous demand for biomedical material consumption is a pointer to the pressing need to develop new sustainable biomaterials. Electrospun materials derived from green polymers have gained popularity in recent years for biomedical applications such as tissue engineering, wound dressings, and drug delivery. Among the various bioengineering materials used in the synthesis of a biodegradable polymer, poly(lactic acid) (PLA) has received the most attention from researchers. Hypericum perforatum oil (HPO) has antimicrobial activity against a variety of bacteria. This study aimed to investigate the development of an antibacterial sustainable material based on PLA by incorporating HPO via a simple, low-cost electrospinning method. Chemical, morphological, thermal, thickness and, air permeability properties, and in vitro antibacterial activity of the electrospun nonwoven fabric were investigated. Scanning electron microscopy (SEM) was used to examine the morphology of the electrospun nonwoven fabric, which had bead-free morphology ultrafine fibers. Antibacterial tests revealed that the Hypericum perforatum oil-loaded poly(lactic acid) nonwoven fabrics obtained had high antibacterial efficiency against Escherichia coli and Staphylococcus aureus, indicating a strong potential for use in biomedical applications.