Abstract
Functionalizing cotton to induce biological activity is a viable approach for developing wound dressing. This study explores the development of cotton-based wound dressing through coating with biologically active nanofibers. Bioactive compounds like lawsone offer dual benefits of wound healing and infection prevention, however, their limited solubility and viability hinder their applications. To address this, Hydroxypropyl-beta-cyclodextrin (HP-β-CD) and Hydroxypropyl-gamma-cyclodextrin (HP-γ-CD) were employed. Inclusion complexations of CD/lawsone were achieved at 2:1 and 4:1 M ratios, followed by the fabrication of CD/lawsone nanofibrous systems via electrospinning. Phase solubility studies indicated a twofold increase in lawsone water-solubility with HP-β-CD. Electrospinning yielded smooth and uniform nanofibers with an average diameter of ∼300–700 nm. The results showed that while specific crystalline peaks of lawsone are apparent in the samples with a 2:1 M ratio, they disappeared in 4:1, indicating complete complexation. The nanofibers exhibited ∼100 % loading efficiency of lawsone and its rapid release upon dissolution. Notably, antibacterial assays demonstrated the complete elimination of Escherichia coli and Staphylococcus aureus colonies. The CD/lawsone nanofibers also showed suitable antioxidant activity ranging from 50 % to 70 %. This integrated approach effectively enhances lawsone’s solubility through CD complexation and offers promise for bilayer cotton-based wound dressings.
Introduction
Wound management represents a pivotal challenge in healthcare, requiring continuous innovation and research. Wound healing is a complex procedure involving various phases such as hemostasis, inflammation, proliferation, and remodeling (Ghiyasi et al., 2023). Factors such as desiccation, infection, necrosis, pressure, and trauma can hinder the wound-healing process (Thomas, 2011). Therefore, a potent wound dressing should besides preserving the wounds from the outer environment, moisturize the skin and prevent infections (Maaz Arif et al., 2021). In this approach, smart wound dressings should not only expedite the healing process but also proactively combat infections, thereby minimizing complications and enhancing patient outcomes.
Cotton as the most dominant cellulosic fiber, has been a cornerstone in medical dressings for over a century, driven by its biocompatibility, intricate structure, moisture retention, comfort properties, and sustainable sourcing (Pinho and Soares, 2018). Although cotton gauze stands as a foundational wound dressing, its limited biological properties and drawbacks such as wound dehydration and bacterial proliferation, necessitate innovative enhancements (Pinho and Soares, 2018, Dhivya et al., 2015). Coating the cotton substrate with a biologically active layer presents a promising approach to fortifying cotton as the outer layer and another layer to facilitate wound healing and prevent infection. In this pursuit, coating nanoparticles (Montaser et al., 2020), hydrogel (Gunes and Ziylan, 2021), and nanofibers (Li et al., 2019) onto cotton substrates has emerged as a transformative strategy. Nanofibers, in particular, have garnered attention due to their resemblance to the extracellular matrix and their potential to emulate skin structure, rendering them invaluable in skin regeneration studies (Rezaei et al., 2022, Law et al., 2017). Their unique attributes, including high surface-to-volume ratio, customizable release profiles, and flexibility to be fabricated with different materials make nanofibers suitable devices for transdermal drug delivery (Asgari et al., 2021, Mendes et al., 2016).
Nanofibrous systems are especially beneficial for coating systems with low-soluble drugs. For fast-dissolving systems and low-soluble drugs, nanofibers with their high surface-to-volume ratio can provide a higher dissolution rate (Balusamy et al., 2020, Kamali et al., 2022). Moreover, nanofibers can act as a potent system to improve drug solubility by preventing premature degradation and enabling the fast wetting and/or disintegration of its dosage form (Kajdič et al., 2020). The high surface-to-volume ratio of the nanofibers can particularly be beneficial for coating systems as they can provide a higher surface area on the first layer. Besides these advantageous features, due to the stability of the jet, producing homogenous nanofibers, and using electrostatic forces that prevent the clumping of fibers, electrospinning results in the formation of uniform nanofibrous coating and preservation of the therapeutics structure throughout the fiber formation process (Berkland et al., 2004, Zhou et al., 2009).
Several reports studied the development of nanofibers-coated cotton as a drug delivery system for wound healing applications. Moazzami Goudarzi et al. facilitated the controlled release of ciprofloxacin, clotrimazole, and benzalkonium chloride by coating the nanofibers on cotton (Moazzami Goudarzi et al., 2022). Notably, as the pursuit of optimal wound management extends beyond single-agent interventions, sometimes dual drug delivery systems should be considered. Moreover, the emergence of antibiotic-resistant bacteria has heightened the urgency to explore novel approaches that can effectively prevent infections and expedite wound closure (Davani et al., 2021, Martínez-Pérez et al., 2023). Natural bioactive agents hold promise in achieving this dual objective, given their biocompatibility, low toxicity, and multifunctional attributes, which can translate into the development of biofunctional wound dressings (Dias et al., 2011, Gaspar-Pintiliescu et al., 2019, Gorain et al., 2022). Lawsone, a naphthoquinone found abundantly in henna leaves (Lawsonia inermis), has garnered attention for its diverse therapeutic properties (Singh et al., 2015). Its antioxidant activity, anti-inflammatory effects, and antimicrobial attributes make it an intriguing prospect for wound management (Sakthiguru and Sithique, 2020, Jridi et al., 2017). It was shown that incorporating lawsone into chitosan/polyethylene oxide nanofibers not only introduced an antithetical property but also reduced the dressing’s cytotoxicity, promoting the cell viability of normal human fibroblast cells (Abadehie et al., 2021). Another study indicated that lawsone antibacterial activity aided wound closure and accelerated wound healing in rat models (Sultana et al., 2021). It was also shown that incorporating lawsone into the nanofibers can promote wound healing by increasing the expressions of TGF-B1 and COL1 genes as well as enhancing re-epithelialization (Adeli-Sardou et al., 2019).
However, the clinical translation of natural bioactive agents particularly lawsone, is encumbered by challenges, including limited solubility and bioavailability. Cyclodextrins (CDs), cyclic oligosaccharides with a hydrophobic core and hydrophilic exterior, are renowned for their ability to form non-covalent inclusion complexes (Wang et al., 2023, Celebioglu and Uyar, 2020). This interaction enhances solubility, stability, and bioavailability, offering a promising avenue for elevating lawsone’s therapeutic impact (Patil et al., 2023). Moreover, these molecules are particularly well-tolerated by the human body (Hsiung et al., 2022). Furthermore, the compatibility of CDs with electrospinning technology underscores their suitability for nanofiber coating on cotton substrates, amplifying their potential in wound dressing applications. The potential of the CD inclusion complexation to enhance the therapeutic efficacy of bioactives has garnered significant attention and validation across diverse research endeavors (Ertan et al., 2023, Celebioglu et al., 2022, Celebioglu et al., 2022). Thus, developing inclusion complexion with cyclodextrin (CD) is a potent approach to increase the solubility and provide stability to lawsone, and prepare nanofibrous coating on the cotton substrate for wound dressing applications. Particularly, it was shown that inclusion complexation with CDs can result in the significant improvement of the antifungal and antiparasitic activities of lawsone, upon increasing its solubility (Nicoletti et al., 2023).
Utilizing the aforementioned features of CDs, the current study aimed to prepare the inclusion complexation of lawsone and hydroxypropyl-beta-cyclodextrin (HP-β-CD) and hydroxypropyl-gamma-cyclodextrin (HP-γ-CD), and then fabrication of nanofibers to be coated on cotton substrate to develop bilayer wound dressing (Fig. 1). This approach offers the opportunity to utilize the full potential of lawsone to functionalize cotton. The morphological, structural, biological, and pharmaco-technical properties of these electrospun nanofibrous films were analyzed through appropriate techniques and approaches.
Section snippets
Materials
Hydroxypropyl-beta-cyclodextrin (HP-β-CD) (Cavasol W7 HP, with a degree of substitution of approximately 0.9) and Hydroxypropyl-gamma-cyclodextrin (HP-γ-CD) (Cavasol W8 HP Pharma, with a degree of substitution of approximately 0.6) were generously provided by Wacker Chemie AG (USA) for laboratory experiments. Lawsone (2-Hydroxy-1,4-naphthoquinone,>98 %, TCI chemicals), methanol (≥99.8 % (GC), Sigma Aldrich), 2,2-diphenyl-1-picrylhydrazyl (DPPH, ≥97 %, TCI America), dimethyl sulfoxide (DMSO,
Phase solubility
The phase solubility was conducted as described by Higuchi and Connors (Higuchi and Connors, 1965), and the results demonstrate the impact of inclusion complexation on the solubility of lawsone. The phase solubility diagrams of HP-β-CD/lawsone and HP-γ-CD/lawsone systems (Fig. 2) indicate that the bioactive solubility increased linearly. This linearity shows an AL-type pattern, indicative of the formation of inclusion complexes with a 1:1 M ratio (Higuchi and Connors, 1965). The results show
Conclusion
Compared to synthetic materials, cotton has many properties that make its substrate ideal for use in wound dressing including high absorbency, hypoallergenic, soft, comfortable, breathable, biodegradable, natural origin, widely available, and easy processing. When developing wound healing patches or any other medical textiles, choosing the right substrate is essential for achieving optimal performance and patient comfort. Although a foundational material in wound dressing, cotton is accompanied ….
