Fabrication of Electrospun Polylactic Acid/Cinnamaldehyde/β-Cyclodextrin Fibers as an Antimicrobial Wound Dressing

Advancements in application of chitosan and cyclodextrins in biomedicine and pharmaceutics: recent progress and future trends

The global community is faced with numerous health concerns such as cancer, cardiovascular and neurological diseases, diabetes, joint pain, osteoporosis, among others. With the advancement of research in the fields of materials chemistry and medicine, pharmaceutical technology and biomedical analysis have entered a new stage of development. The utilization of natural oligosaccharides and polysaccharides in pharmaceutical/biomedical studies has gained significant attention. Over the past decade, several studies have shown that chitosan and cyclodextrin have promising biomedical implications in background analysis, ongoing development, and critical applications in biomedical and pharmaceutical research fields. This review introduces different types of saccharides/natural biopolymers such as chitosan and cyclodextrin and discusses their wide-ranging applications in the biomedical/pharmaceutical research area. Recent research advances in pharmaceutics and drug delivery based on cyclodextrin, and their response to smart stimuli, as well as the biological functions of cyclodextrin and chitosan, such as the immunomodulatory effects, antioxidant, and antibacterial properties, have also been discussed, along with their applications in tissue engineering, wound dressing, and drug delivery systems. Finally, the innovative applications of chitosan and cyclodextrin in the pharmaceutical/biomedicine were reviewed, and current challenges, research/technological gaps, and future development opportunities were surveyed.

Functional electrospun nanofibers: fabrication, properties, and applications in wound-healing process

Electrostatic spinning as a technique for producing nanoscale fibers has recently attracted increasing attention due to its simplicity, versatility, and loadability. Nanofibers prepared by electrostatic spinning have been widely studied, especially in biomedical applications, because of their high specific surface area, high porosity, easy size control, and easy surface functionalization. Wound healing is a highly complex and dynamic process that is a crucial step in the body's healing process to recover from tissue injury or other forms of damage. Single-component nanofibers are more or less limited in terms of structural properties and do not fully satisfy various needs of the materials. This review aims to provide an in-depth analysis of the literature on the use of electrostatically spun nanofibers to promote wound healing, to overview the infinite possibilities for researchers to tap into their biomedical applications through functional composite modification of nanofibers for advanced and multifunctional materials, and to propose directions and perspectives for future research.

Chronic toxicity of biodegradable microplastic (Polylactic acid) to Daphnia magna: A comparison with polyethylene terephthalate

The increase in the usage of biodegradable microplastics (MPs) as an alternative to conventional plastics has necessitated comprehensive ecotoxicity assessments of biodegradable MPs alongside conventional MPs. This study aimed to assess ecotoxicity of biodegradable polylactic acid (PLA) MPs at concentration of 1 and 5 mgL-1 including a genetic analysis of Daphnia magna, and compared to effects of conventional polyethylene terephthalate (PET) MPs. The survival rate for D. magna exposed to 5 mg L-1 of PLA-MPs declined to 52.4 %, signifying a higher rate of mortality when contrasted with PET-MPs, which exhibited 85.7 % survival rate. Chronic exposure to 1 and 5 mgL-1 PLA-MPs resulted in a decrease of offspring, while increasing the sex ratio and deformed embryo. Interestingly, down-regulation of the SOD and AK genes was observed in D. magna after exposure to 5 mgL-1 of PLA-MPs, while 1 mgL-1 of PLA-MPs up-regulated. These results means that 5 mgL-1 PLA-MP could not produce energy and cope with oxidative stress, resulting in high mortality, and 1 mgL-1 of MP was maintained survival due to energy production and antioxidant action. This study contributes to our understanding of biodegradable microplastics (BMPs) toxic effects on D. magna which could be similar to conventional MPs and provide the importance of ecotoxicological data for risk assessment of BMPs in aquatic organisms.

Multifunctional bilayer membranes composed of poly(lactic acid), beta-chitin whiskers and silver nanoparticles for wound dressing applications

Nanomaterial-based wound dressings have been extensively studied for the treatment of both minor and life-threatening tissue injuries. These wound dressings must possess several crucial characteristics, such as tissue compatibility, non-toxicity, appropriate biodegradability to facilitate wound healing, effective antibacterial activity to prevent infection, and adequate physical and mechanical strength to withstand repetitive dynamic forces that could potentially disrupt the healing process. Nevertheless, the development of nanostructured wound dressings that incorporate various functional micro- and nanomaterials in distinct architectures, each serving specific purposes, presents significant challenges. In this study, we successfully developed a novel multifunctional wound dressing based on poly(lactic acid) (PLA) fibrous membranes produced by solution-blow spinning (SBS) and electrospinning. The PLA-based membranes underwent surface modifications aimed at tailoring their properties for utilization as effective wound dressing platforms. Initially, beta-chitin whiskers were deposited onto the membrane surface through filtration, imparting hydrophilic character. Afterward, silver nanoparticles (AgNPs) were incorporated onto the beta-chitin layer using a spray deposition method, resulting in platforms with antimicrobial properties against both Staphylococcus aureus and Escherichia coli. Cytotoxicity studies demonstrated the biocompatibility of the membranes with the neonatal human dermal fibroblast (HDFn) cell line. Moreover, bilayer membranes exhibited a high surface area and porosity (> 80%), remarkable stability in aqueous media, and favorable mechanical properties, making them promising candidates for application as multifunctional wound dressings.

Fabrication and Characterization of Polylactic Acid Electrospun Wound Dressing Modified with Polyethylene Glycol, Rosmarinic Acid and Graphite Oxide

Polylactic acid (PLA) is a biodegradable polymer made from natural sources, and its electrospinning (e-spinning) nanofiber membrane doped with antibacterial ingredients is widely used in the field of medical dressings. In this research, 9 wt% of rosmarinic acid (RosA) and 0.04 wt% of graphite oxide (GO) with synergistic antibacterial activity were introduced into the e-spinning PLA precursor solution, and the obtained PLA nanofiber membrane showed good antibacterial properties and wound healing effects. At the same time, a nonionic amphiphilic polymer, polyethylene glycol (PEG), was also introduced into this system to improve the hydrophilicity of the e-spinning membrane for wound healing application. The morphological characterization showed the RosA/GO and PEG did not affect the e-spinning of PLA. The tests of mechanical performance and wettability demonstrated that PEG and RosA/GO incorporated in PLA have migrated easily to the surface of the fiber. The e-spun PLA/PEG/RosA/GO membrane showed good antibacterial activity and promoted initial wound healing quickly, which would be a promising application in wound dressing.

Cinnamaldehyde-Based Self-Nanoemulsion (CA-SNEDDS) Accelerates Wound Healing and Exerts Antimicrobial, Antioxidant, and Anti-Inflammatory Effects in Rats’ Skin Burn Model

Cinnamaldehyde, the main phytoconstituent of the cinnamon oil, has been reported for its potential wound healing activity, associated to its antimicrobial and anti-inflammatory effects. In this study, we are reporting on the cinnamaldehyde-based self-nanoemulsifying drug delivery system (CA-SNEDDS), which was prepared and evaluated for its antimicrobial, antioxidant, anti-inflammatory, and wound healing potential using the rat third-degree skin injury model. The parameters, i.e., skin healing, proinflammatory, and oxidative/antioxidant markers, were evaluated after 3 weeks of treatment regimens with CA-SNEDDS. Twenty rats were divided randomly into negative control (untreated), SNEDDS control, silver sulfadiazine cream positive control (SS), and CA-SNEDDS groups. An aluminum cylinder (120 °C, 10-s duration) was used to induce 3rd-degree skin burns (1-inch square diameter each) on the rat’s dorsum. At the end of the experiment, skin biopsies were collected for biochemical analysis. The significantly reduced wound size in CA-SNEDDS compared to the negative group was observed. CA-SNEDDS-treated and SS-treated groups demonstrated significantly increased antioxidant biomarkers, i.e., superoxide dismutase (SOD) and catalase (CAT), and a significant reduction in the inflammatory marker, i.e., NAP-3, compared to the negative group. Compared to SNEDDS, CA-SNEDDS exhibited a substantial antimicrobial activity against all the tested organisms at the given dosage of 20 µL/disc. Among all the tested microorganisms, MRSA and S. typhimurium were the most susceptible bacteria, with an inhibition zone diameter (IZD) of 17.0 ± 0.3 mm and 19.0 ± 0.9 mm, respectively. CA-SNEDDS also exhibited strong antifungal activity against C. albicans and A. niger, with IZD of 35.0 ± 0.5 mm and 34.0 ± 0.5 mm, respectively. MIC and MBC of CA-SNEDDS for the tested bacteria ranged from 3.125 to 6.25 µL/mL and 6.25 to 12.5 µL/mL, respectively, while the MIC and MBC for C. albicans and A. niger were 1.56 µL/mL and 3.125 µL/mL, respectively. The MBIC and MBEC of CA-SNEDDS were also very significant for the tested bacteria and ranged from 6.25 to 12.5 µL/mL and 12.5 to 25.0 µL/mL, respectively, while the MBIC and MBEC for C. albicans and A. niger were 3.125 µL/mL and 6.25 µL/mL, respectively. Thus, the results indicated that CA-SNEDDS exhibited significant wound healing properties, which appeared to be attributed to the formulation’s antimicrobial, antioxidant, and anti-inflammatory effects.

Development of active packaging films based on liquefied shrimp shell chitin and polyvinyl alcohol containing β-cyclodextrin/cinnamaldehyde inclusion

To maintain the freshness of fruits and to meet environmental and consumer needs, a biobased packaging film with long-lasting antimicrobial activity was developed in this article. Liquefied ball-milled shrimp shell chitin/polyvinyl alcohol (LBSC/PVA) blend films containing varying concentrations (0, 1, 2, 3, 4, 5 wt%) of the β-cyclodextrin/cinnamaldehyde (β-CD/CA) inclusion were prepared and characterized. The association between β-CD and CA and the sustained release behavior of CA were explored. The physicochemical property, antimicrobial activity and food preservation performance of the films were investigated. Results showed that CA was successfully encapsulated into the cavity of CD by host-guest interactions, which greatly improved the sustained release of CA. The 3 wt% β-CD/CA/LBSC/PVA blend film showed optimized mechanical properties with a tensile strength of 41.5 MPa and an elongation at break of 810 %. In addition, the incorporation of β-CD/CA inclusion significantly enhanced the antimicrobial activity and food preservation performance of the blend films. Moreover, the 3 wt% β-CD/CA/LBSC/PVA blend film exhibited evidently longer lasting antimicrobial activity and cherry tomato preservation performance than the 3 wt% CA/LBSC/PVA blend film, further demonstrating the critical role of β-CD in delaying CA release. These novel β-CD/CA/LBSC/PVA blend films may have a potential use in active food packaging.

NIR-regulated dual-functional silica nanoplatform for infected-wound therapy via synergistic sterilization and anti-oxidation

Nature-derived bioactive components and photothermal synergistic therapy bring potential strategies for fighting bacterial infection and accelerating would healing by virtue of their excellent therapeutic efficiencies and ignorable side effects, where photothermal property not only acts as sterilization energy but also as a doorkeeper to control the natural component release. Herein, by integrating the excellent antibacterial property of cinnamaldehyde (CA) and the outstanding photothermal performance of copper sulfide nanoparticles (CuS NPs), a multifunctional nanoplatform of SiO₂ @CA@CuS nanospheres (NSs) is constructed with silica nanosphere (SiO₂ NSs) as carrier. SiO₂ @CA@CuS NSs exhibit photothermal property, bacterial absorption capacity, extraordinary antibacterial activity and antioxidant property. Mechanism characteriazation and antibacterial experiment indicate that positive charged SiO₂ @CA@CuS can adhere to the negative charged surface of bacteria, and quickly kill bacteria through the synergistic action of the released CA and heat produced under near infrared light (NIR) irradiation at 980 nm. The sterilization efficiencies for Escherichia coli (E. coli) and S. aureus reach 99.86% and 99.84%, respectively. Furthermore, NIR-regulated SiO₂ @CA@CuS perform great biocompatibility, as well as effective effects for accelerating S. aureus-infected wound healing at a low photothermal temperature (45 °C) relying on synergistic sterilization and anti-oxidation.

Dual Spinneret Electrospun Polyurethane/PVA-Gelatin Nanofibrous Scaffolds Containing Cinnamon Essential Oil and Nanoceria for Chronic Diabetic Wound Healing: Preparation, Physicochemical Characterization and In-Vitro Evaluation

In this study, a dual spinneret electrospinning technique was applied to fabricate a series of polyurethane (PU) and polyvinyl alcohol-gelatin (PVA/Gel) nanofibrous scaffolds. The study aims to enhance the properties of PU/PVA-Gel NFs loaded with a low dose of nanoceria through the incorporation of cinnamon essential oil (CEO). The as-prepared nCeO2 were embedded into the PVA/Gel nanofibrous layer, where the cinnamon essential oil (CEO) was incorporated into the PU nanofibrous layer. The morphology, thermal stability, mechanical properties, and chemical composition of the produced NF mats were investigated by STEM, DSC, and FTIR. The obtained results showed improvement in the mechanical, and thermal stability of the dual-fiber scaffolds by adding CEO along with nanoceria. The cytotoxicity evaluation revealed that the incorporation of CEO to PU/PVA-Gel loaded with a low dose of nanoceria could enhance the cell population compared to using pure PU/PVA-Gel NFs. Moreover, the presence of CEO could inhibit the growth rate of S. aureus more than E. coli. To our knowledge, this is the first time such nanofibrous membranes composed of PU and PVA-Gel have been produced. The first time was to load the nanofibrous membranes with both CEO and nCeO2. The obtained results indicate that the proposed PU/PVA-Gel NFs represent promising platforms with CEO and nCeO2 for effectively managing diabetic wounds.

Cinnamaldehyde as antimicrobial in cellulose-based dental appliances

AIMS

In the context of minor orthodontic intervention using clear aligner technologies, we determined antimicrobial properties of a cellulose-based material loaded with essential oils such as cinnamaldehyde.

METHODS AND RESULTS

Isothermal microcalorimetry was used to assess the growth of bacterial biofilms at the interface between the tested material and the solid growth medium. The calorimetric data were analyzed using conventional growth models (Gompertz and Richards), and inhibition at 12 and 24 h was calculated.

CONCLUSIONS

The tested material showed antimicrobial properties against Staphylococcus epidermidis as well as Streptococcus mutans and Streptococcus mitis clinical isolates. The inhibition was more pronounced against S. epidermidis, for which growth rate was reduced by 70% and lag phase was extended by 12 h. For S. mutans and S. mitis, the decrease in growth rate was 20% and 10%, and the lag phase increased by 2 and 6 h, respectively.

SIGNIFICANCE AND IMPACT

Clear aligners for minor teeth alignment are becoming very popular. As they must be worn for at least 22 h per day for up to 40 weeks, it is important that they remain clean and do not promote caries formation or other oral infections. Therefore, introducing material with antimicrobial properties is expected to maintain oral hygiene during the aligner therapy. Here, we demonstrate the use of cinnamaldehyde for reducing microbial growth and biofilm formation on cellulose-based dental clear aligners.

Advances and Classification of Cyclodextrin-Based Polymers for Food-Related Issues

Cyclodextrins (CDs) are a good alternative to reduce or enhance different biomolecule characteristics and have demonstrated great results in food science. However, CDs present intrinsic limitations that can be solved by derivative synthesis. This review represents a survey of the state of the art of CD-based materials and their uses in food science. A deep review of the structure is carried out and different groups for ordination are suggested. After that, different applications such as cholesterol complexation or its use as sensors are reviewed. The derivatives show novel and promising activities for the industry. A critical perspective of the materials suggests that they might not present toxicity, although more studies are required. These points suggest that the research in this field will be increased in the following years.

Recent advances in polymer scaffolds for biomedical applications

The review provides insights into current advancements in electrospinning-assisted manufacturing for optimally designing biomedical devices for their prospective applications in tissue engineering, wound healing, drug delivery, sensing, and enzyme immobilization, and others. Further, the evolution of electrospinning-based hybrid biomedical devices using a combined approach of 3 D printing and/or film casting/molding, to design dimensionally stable membranes/micro-nanofibrous assemblies/patches/porous surfaces, etc. is reported. The influence of various electrospinning parameters, polymeric material, testing environment, and other allied factors on the morphological and physico-mechanical properties of electrospun (nano-/micro-fibrous) mats (EMs) and fibrous assemblies have been compiled and critically discussed. The spectrum of operational research and statistical approaches that are now being adopted for efficient optimization of electrospinning process parameters so as to obtain the desired response (physical and structural attributes) has prospectively been looked into. Further, the present review summarizes some current limitations and future perspectives for modeling architecturally novel hybrid 3 D/selectively textured structural assemblies, such as biocompatible, non-toxic, and bioresorbable mats/scaffolds/membranes/patches with apt mechanical stability, as biological substrates for various regenerative and non-regenerative therapeutic devices.

Flexible mats as promising antimicrobial systems via integration of Thymus capitatus (L.) essential oil into PLA

Aim: To develop electrospun mats loaded with Thymus capitatus (L.) essential oil (ThymEO) and to study their morpho-mechanical and antimicrobial properties. Materials & methods: Poly(lactic acid) (PLA) mats containing ThymEO were prepared by electrospinning. The effect of ThymEO on the morpho-mechanical properties of fibers was assayed by scanning electron microscopy and dynamometer measurements. The antimicrobial activity of ThymEO delivered either in liquid or vapor phase was assessed through killing curves and invert Petri dishes method. The cytotoxicity was also investigated. Results: The mechanical properties were enhanced by integrating ThymEO into PLA. Both liquid and vapors of ThymEO released from mats caused reductions of microbial viable cells. Negligible cytotoxicity was demonstrated. Conclusion: PLA/ThymEO delivery systems could be suitable for treating microbial infections.

Chitosan-Coated Poly(lactic acid) Nanofibres Loaded with Essential Oils for Wound Healing

Chronic skin wounds are characterised by a non-healing process that makes necessary the application of wound dressings on the damaged area to promote and facilitate the recovery of skin’s physiological integrity. The aim of the present work is to develop a bioactive dressing that, once applied on the injured tissue, would exert antibacterial activity and promote adhesion and proliferation of fibroblasts. Nanofibres consisting of poly(lactic acid) (PLA) and essential oils (EOs) were electrospun and coated with a medium molecular weight chitosan (CS). Black pepper essential oil (BP-EO) or limonene (L), well-known for their antibacterial properties, were added to the PLA/acetone solution before electrospinning; phase separation phenomena occurred due to the poor solubility of the EOs in the PLA solution and led to fibres having surface nano-pores. The porous electrospun fibres were coated with CS to produce hydrophilic membranes that were easy to handle, biocompatible, and suited to promote cellular proliferation. The fibrous scaffolds were tested in terms of mechanical resistance, wettability, antibacterial activity, in-vitro cytotoxicity, and ability to promote fibroblasts’ adhesion and proliferation. The results obtained proved that the CS coating improved the hydrophilicity of the fibrous mats, enhanced EO’s antibacterial potential, and promoted cell adhesion and proliferation.

Biodegradable and Biocompatible 3D Constructs for Dental Applications: Manufacturing Options and Perspectives

Designing 3D constructs with appropriate materials and structural frameworks for complex dental restorative/regenerative procedures has always remained a multi-criteria optimization challenge. In this regard, 3D printing has long been known to be a potent tool for various tissue regenerative applications, however, the preparation of biocompatible, biodegradable, and stable inks is yet to be explored and revolutionized for overall performance improvisation. The review reports the currently employed manufacturing processes for the development of engineered self-supporting, easily processable, and cost-effective 3D constructs with target-specific tuneable mechanics, bioactivity, and degradability aspects in the oral cavity for their potential use in numerous dental applications ranging from soft pulp tissues to hard alveolar bone tissues. A hybrid synergistic approach, comprising of development of multi-layered, structurally stable, composite building blocks with desired physicomechanical performance and bioactivity presents an optimal solution to circumvent the major limitations and develop new-age advanced dental restorations and implants. Further, the review summarizes some manufacturing perspectives which may inspire the readers to design appropriate structures for clinical trials so as to pave the way for their routine applications in dentistry in the near future.

Preparation of cypress (Cupressus sempervirens L.) essential oil loaded poly(lactic acid) nanofibers

This study investigated the production of poly(lactic acid) (PLA) nanofibers containing cypress (CUP) essential oil (EO) via electrospinning. The nanofibers were produced from polymer solution prepared with different percentages of cypress EO. Cypress EO-containing PLA nanofibers were characterized and some mechanical and thermal properties were examined using thermogravimetric analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and dynamic mechanical analysis. The thermal stability of the nanofibers was reduced depending on the percentage of the cypress EO. As the ratio of the cypress EO to polymer matrices was increased, it was observed that the glassy transition temperatures of the nanofibers decreased and their flexibility increased. The T g value was determined to be 53.74°C for the neat PLA nanofiber, while 51.83°C for the PLA-CUP nanofiber (containing 15% cypress EO). According to the results of releasing trial, the increased amount of cypress EO resulted in less cypress EO releasing from polymer matrices. The nanofibers were observed to exhibit antibacterial activity against Escherichia coli and Staphylococcus aureus. The inhibition zone diameter of the nanofibers containing 10% cypress EO was 20 mm for S. aureus and 16 mm for E. coli, while 10 mm in the presence of Kanamycin.

Multi-layered in vitro 3D-bone model via combination of osteogenic cell sheets with electrospun membrane interlayer

In this study, it was aimed to present an approach for the development of multi-layered tissue engineering constructs by using cell sheet engineering. Briefly, MC3T3-E1 mouse pre-osteoblast cells were cultured in temperature-responsive plates (Nunc Upcell®) in the presence of osteogenic medium and the resulting cell sheets were laminated with electrospun poly(L-lactic acid) (PLLA) membranes to obtain viable three-dimensional, thick constructs. The constructs prepared without PLLA membranes were used as control. The cell viability and death in the resulting structures were investigated by microscopic and colorimetric methods. The in vitro performance of the structures was discussed comparatively. Alkaline phosphatase (ALP) activity, collagen and sulfated glycosaminoglycan (sGAG) content values were calculated. The presented approach shows potential for engineering applications of complex tissues with at least two or more microenvironments such as osteochondral, corneal or vascular tissues.

Physicomechanical performance and encapsulation efficiency of β-cyclodextrin loaded functional electrospun mats based on aliphatic polyesters and their blends

Designing complex-forming biodegradable and biocompatible electrospun mats (EMs) by incorporating β- cyclodextrin (β-CD) into polylactic acid (PLA)/poly(ε-caprolactone) (PCL) (70:30 w/w) blend based polyester matrix. The influence of β-CD loading on the morphological, thermal, and microstructural properties was investigated using scanning electron microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The studies revealed the presence of characteristic interactions between the polymer matrix and β-CD moieties. Further, the quasi-static mechanical properties of EMs were evaluated using a universal testing machine. An enhancement in modulus and strength was obtained for ∼ 2.5-5 phr of β-CD content and beyond ∼ 5 phr of β-CD content, the mechanical properties of EMs were observed to deteriorate. The contact angle studies indicated a decrease in hydrophobicity of PLA/PCL-based EMs with the increase in β-CD content. The swelling and weight loss studies in phosphate buffer saline (PBS) indicated a subsequent release of β-CD from the EMs. FT-IR and ¹H NMR spectra elucidated the removal of curcumin from ethanol-water solutions and its simultaneous encapsulation in β-CD hydrophobic cavities (released) of fabricated EMs. Thus, the study demonstrates the development of aliphatic polyester-based biodegradable-functional EMs with tunable physico-mechanical properties for biomedical applications, facilitating encapsulation and rapid removal of waste hydrophobic ultrafine molecules from the system.

Optimally controlled morphology and physico-mechanical properties of inclusion complex loaded electrospun polyvinyl alcohol based nanofibrous mats for therapeutic applications

Hydrophilic polyvinyl alcohol (PVA) based electrospun nanofibrous mats (ENMs) are recently being used for the designing and fabrication of active wound dressing materials. Thus, in this study an inclusion complex (IC) of curcumin (CUR) and β-cyclodextrin (β-CD) was optimally incorporated in electrospun PVA nanofibers, to obtain uniform bead-free nanofibers with minimum average diameter and variation using Taguchi's design of experiments (DOE). The optimum level parameters were ascertained using Taguchi's methodology, to obtain IC loaded PVA based bead-free ENMs, by varying IC (∼20, ∼40, and ∼60 wt.%) loading, applied voltage, solution concentration, and N, N-dimethylformamide (DMF) content in the electrospinning solution mixture. Validation experiments revealed a good agreement between the predicted and experimental values of fiber diameter, diameter-variation, and bead-numbers. Analysis of variance (ANOVA) showed a major influence of IC loading on the average fiber diameter and the number of bead defects, for IC-loaded PVA based ENMs. However, the DMF content of the solvent mixture significantly influenced the diameter variations of ENMs. The surface morphologies of ENMs were analyzed using Scanning Electron Microscopy (SEM) whereas the microstructural aspects were studied by Wide-Angle X-ray Diffraction (WAXD) and Fourier transform infrared (FT-IR) spectroscopy. The thermal properties were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) whereas the mechanical properties were measured by using uniaxial tensile testing and dynamic mechanical analysis (DMA). The variation in properties of IC loaded PVA based ENMs were correlated with neat PVA based ENMs fabricated using a similar set of optimized electrospinning process parameters. The study conceptually demonstrated the optimal designing of structurally-engineered hydrophilic IC loaded PVA based ENMs by using the Taguchi approach based on orthogonal DOE as potential drug release substrates.

Nanostructured Oxide-Based Systems for the pH-Triggered Release of Cinnamaldehyde

Cinnamaldehyde is a natural product with antibacterial, antifungal, and anti-inflammatory properties, poorly stable in environmental conditions. Systems for the controlled release of cinnamaldehyde are of great interest to the food and pharmaceutical industries. Here, a new oxide-based construct for the release of cinnamaldehyde catalyzed by acidic pH was obtained by a facile grafting method based on amino-silane linkers and imine chemistry. The grafting procedure led to a loading of ca. 5 molecules/nm2, determined on oxide powders with CHN and TGA measurements. The covalent grafting of cinnamaldehyde, demonstrated by FTIR analyses, preserved the molecule stability, simplifying storage. Release tests were performed at different pH values (between 5.0 and 7.4). Thanks to imine chemistry, a fast cinnamaldehyde (CIN) release was observed in a pH 5.0 environment. Using 1 mg/mL suspensions, CIN concentrations within the range adopted in the food industry were obtained (12.4 ppm). The grafting procedure was also performed on a porous film based on a photocatalytic oxide, demonstrating the versatility of this method, adaptable to both powders and macroscopic materials. By taking advantage of the photoactivity of the oxide, regeneration of the fouled film was achieved upon UV irradiation for 1 h, opening the door to reusable devices for the controlled release of cinnamaldehyde.

Recent trends on wound management: New therapeutic choices based on polymeric carriers

Wound healing is an unmet therapeutic challenge among medical society since wound assessment and management is a complex procedure including several factors playing major role in healing process. Wounds can mainly be categorized as acute or chronic. It is well referred that the acute wound displays normal wound physiology while healing, in most cases, is seemed to progress through the normal phases of wound healing. On the other hand, a chronic wound is physiologically impaired. The main problem in wound management is that the majority of wounds are colonized with microbes, whereas this does not mean that all wounds will be infected. In this review, we address the problems that clinicians face to manage while treat acute and chronic wounds. Moreover, we demonstrate the pathophysiology, etiology, prognosis and microbiology of wounds. We further introduce the state of art in pharmaceutical technology field as part of wound management aiming to assist health professionals to overcome the current implications on wound assessment. In addition, authors review researches which included the use of gels and dermal films as wound healing agents. It can be said that natural and synthetic drugs or carriers provide promising solutions in order to meet the wound management standards. However, are the current strategies as desirable as medical society wish?

Repositioning Natural Antioxidants for Therapeutic Applications in Tissue Engineering

Although a large panel of natural antioxidants demonstrate a protective effect in preventing cellular oxidative stress, their low bioavailability limits therapeutic activity at the targeted injury site. The importance to deliver drug or cells into oxidative microenvironments can be realized with the development of biocompatible redox-modulating materials. The incorporation of antioxidant compounds within implanted biomaterials should be able to retain the antioxidant activity, while also allowing graft survival and tissue recovery. This review summarizes the recent literature reporting the combined role of natural antioxidants with biomaterials. Our review highlights how such functionalization is a promising strategy in tissue engineering to improve the engraftment and promote tissue healing or regeneration.

Cinnamaldehyde incorporated gellan/PVA electrospun nanofibers for eradicating Candida biofilm

Immunocompromised patients encounter fungal infections more frequently than healthy individuals. Conventional drugs associated health risk and resistance, portrayed fungal infections as a global health problem. This issue needs to be answered immediately by designing a novel anti-fungal therapeutic agent. Phytoactive molecules based therapeutics are most suitable candidate due to their low cytotoxicity and minimal side effects to the host. In this study, cinnamaldehyde (CA), an FDA approved phytoactive molecule present in cinnamon essential oil was incorporated into gellan (GA)/poly vinyl alcohol (PVA) based electrospun nanofibers to resolve the issues like low water solubility, high volatility and irritant effect associated with CA and also to enhance its therapeutic applications. The drug encapsulation, morphology and physical properties of the synthesized CA nanofibers were evaluated by FESEM, AFM, TGA, FTIR and static water contact angle analysis. The average diameters of CA encapsulated GA/PVA nanofibers and GA/PVA nanofibers were recorded to be 278.5 ± 57.8 nm and 204.03 ± 39.14 nm, respectively. These nanofibers were evaluated for their anti-biofilm activity against Candida using XTT (2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl]-2H-tetrazolium salt) reduction assay. Data demonstrated that CA encapsulated GA/PVA nanofibers can effectively eradicate 89.29% and 50.45% of Candida glabrata and Candida albicans biofilm respectively. CA encapsulated nanofibers exhibited brilliant antimicrobial property against Staphylococcus aureus and Pseudomonas aeruginosa. The cytotoxicity assay demonstrated that nanofibers loaded with CA have anticancer properties as it reduces cell viability of breast cancer cells (MCF-7) by 27.7%. These CA loaded GA/PVA (CA-GA/PVA) nanofibers could be used as novel wound dressing material and coatings on biomedical implants to eradicate biofilm.

Tailored-design of electrospun nanofiber cellulose acetate/poly(lactic acid) dressing mats loaded with a newly synthesized sulfonamide analog exhibiting superior wound healing

To effectively allow for controlled release of a newly synthesized sulfonamide analog, biodegradable poly(lactic acid) nanofibrous dressing mats tailored-designed for maximum wound healing efficacy were developed. The heterocyclic analog, N-(3,4-diamino-7-(benzo [d]thiazol-2-yl)-6-oxo-1H-pyrazolo[4,3-c]pyridin-5(6H)-yl)benzenesulfonamide, has been specifically synthesized to possess superior antibacterial and anti-inflammatory characteristics. Hydrophilic cellulose acetate and/or poly(ethylene oxide) were blended with the hydrophobic PLA to control the hydrophilicity/hydrophobicity ratio for the sustained release of the drug. SEM detected no drug crystals on the surface of the nanofibers confirming the homogeneous dispersion and compatibility of the drug with the nanofibers. BET indicated almost-reversible Type II sorption isotherms. The swelling studies revealed that the presence of hydrogen bonds between the hydroxyl groups of CA with the carbonyl ester groups of PLA limited the ability of CA molecules to leach from the polymer matrix. Water vapor permeability were all determined to be within the range of 15-19 g/m²/h. In-vitro cell viability and cell proliferation studies revealed the superiority of the fabricated dressing mats in terms of its bioactivity and cellular interaction. In-vivo studies confirmed the major improvement in its wound healing capabilities attributed to an enhanced epithelization, anti-inflammation, neo-angiogenesis, fibroplasias and collagen deposition that surpassed that of commercially available ones.

Supramolecular Interactions in Hybrid Polylactide Blends-The Structures, Mechanisms and Properties

The conformation of polylactide (PLA) chains can be adjusted by supramolecular interactions (the formation of hydrogen bonds or host-guest complexes) with appropriate organic molecules. The structures formed due to those intermolecular interactions may act as crystal nuclei in the PLA matrix ("soft templating"). In this review, the properties of several supramolecular nucleating systems based on synthetic organic nucleators (arylamides, hydrazides, and 1,3:2,4-dibenzylidene-d-sorbitol) are compared to those achieved with biobased nucleating agents (orotic acid, humic acids, fulvic acids, nanocellulose, and cyclodextrins) that can also improve the mechanical properties of PLA. The PLA nanocomposites containing both types of nucleating agents/additives are discussed and evaluated in the context of their biomedical applicability.

Nanostructured Fibers Containing Natural or Synthetic Bioactive Compounds in Wound Dressing Applications

The interest in wound healing characteristics of bioactive constituents and therapeutic agents, especially natural compounds, is increasing because of their therapeutic properties, cost-effectiveness, and few adverse effects. Lately, nanocarriers as a drug delivery system have been actively investigated and applied in medical and therapeutic applications. In recent decades, researchers have investigated the incorporation of natural or synthetic substances into novel bioactive electrospun nanofibrous architectures produced by the electrospinning method for skin substitutes. Therefore, the development of nanotechnology in the area of dressings that could provide higher performance and a synergistic effect for wound healing is needed. Natural compounds with antimicrobial, antibacterial, and anti-inflammatory activity in combination with nanostructured fibers represent a future approach due to the increased wound healing process and regeneration of the lost tissue. This paper presents different approaches in producing electrospun nanofibers, highlighting the electrospinning process used in fabricating innovative wound dressings that are able to release natural and/or synthetic substances in a controlled way, thus enhancing the healing process.

Biofunctionalization of Textile Materials. 2. Antimicrobial Modification of Poly(lactide) (PLA) Nonwoven Fabricsby Fosfomycin

This research is focused on obtaining antimicrobial hybrid materials consisting of poly(lactide) nonwoven fabrics and using phosphoro-organic compound—fosfomycin—as a coating and modifying agent. Polylactide (PLA) presents biodegradable polymer with multifunctional application, widely engaged in medical related areas. Fosfomycin as functionalized phosphonates presents antibiotic properties expressed by broad spectrum of antimicrobial properties. The analysis of these biofunctionalized nonwoven fabrics processed by the melt-blown technique, included: scanning electron microscopy (SEM), UV/VIS transmittance, FTIR spectrometry, air permeability. The functionalized nonwovens were tested on microbial activity tests against colonies of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria.

Molecular Encapsulation of Cinnamaldehyde within Cyclodextrin Inclusion Complex Electrospun Nanofibers: Fast-Dissolution, Enhanced Water Solubility, High Temperature Stability, and Antibacterial Activity of Cinnamaldehyde

The electrospinning of nanofibers (NFs) of cinnamaldehyde inclusion complexes (ICs) with two different hydroxypropylated cyclodextrins (CDs), hydroxypropyl-β-cyclodextrin (HP-β-CD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CD), was successfully performed in order to produce cinnamaldehyde/CD-IC NFs without using an additional polymer matrix. The inclusion complexation between cinnamaldehyde and hydroxypropylated CDs was studied by computational molecular modeling, and the results suggested that HP-β-CD and HP-γ-CD can be inclusion complexed with cinnamaldehyde at 1:1 and 2:1 (cinnamaldehyde/CD) molar ratios. Additionally, molecular modeling and phase solubility studies showed that water solubility of cinnamaldehyde dramatically increases with cyclodextrin inclusion complex (CD-IC) formation. The HP-β-CD has shown slightly stronger binding with cinnamaldehyde when compared to HP-γ-CD for cinnamaldehyde/CD-IC. Although cinnamaldehyde is a highly volatile compound, it was effectively preserved with high loading by the cinnamaldehyde/CD-IC NFs. It was also observed that cinnamaldehyde has shown much higher temperature stability in cinnamaldehyde/CD-IC NFs compared to uncomplexed cinnamaldehyde because of the inclusion complexation state of cinnamaldehyde within the hydroxypropylated CD cavity. Moreover, cinnamaldehyde still has kept its antibacterial activity in cinnamaldehyde/CD-IC NF samples when tested against Escherichia coli. In addition, cinnamaldehyde/CD-IC NF mats were fast-dissolving in water, even though pure cinnamaldehyde has a water-insoluble nature. In brief, self-standing nanofibrous mats of electrospun cinnamaldehyde/CD-IC NFs are potentially applicable in food, oral-care, healthcare, and pharmaceutics because of their fast-dissolving character, enhanced water solubility, stability at elevated temperature, and promising antibacterial activity.

Electrospinning of Cyclodextrin Functional Nanofibers for Drug Delivery Applications

Electrospun nanofibers have sparked tremendous attention in drug delivery since they can offer high specific surface area, tailored release of drugs, controlled surface chemistry for preferred protein adsorption, and tunable porosity. Several functional motifs were incorporated into electrospun nanofibers to greatly expand their drug loading capacity or to provide the sustained release of the embedded drug molecules. In this regard, cyclodextrins (CyD) are considered as ideal drug carrier molecules as they are natural, edible, and biocompatible compounds with a truncated cone-shape with a relatively hydrophobic cavity interior for complexation with hydrophobic drugs and a hydrophilic exterior to increase the water-solubility of drugs. Further, the formation of CyD-drug inclusion complexes can protect drug molecules from physiological degradation, or elimination and thus increases the stability and bioavailability of drugs, of which the release takes place with time, accompanied by fiber degradation. In this review, we summarize studies related to CyD-functional electrospun nanofibers for drug delivery applications. The review begins with an introductory description of electrospinning; the structure, properties, and toxicology of CyD; and CyD-drug complexation. Thereafter, the release of various drug molecules from CyD-functional electrospun nanofibers is provided in subsequent sections. The review concludes with a summary and outlook on material strategies.

Electrospun vascular grafts fabricated from poly(L-lactide-co-ε-caprolactone) used as a bypass for the rabbit carotid artery

The study involved the electrospinning of the copolymer poly(L-lactide-co-ε-caprolactone) (PLCL) into tubular grafts. The subsequent material characterization, including micro-computed tomography analysis, revealed a level of porosity of around 70%, with pore sizes of 9.34 ± 0.19 μm and fiber diameters of 5.58 ± 0.10 μm. Unlike fibrous polycaprolactone, the electrospun PLCL copolymer promoted fibroblast and endothelial cell adhesion and proliferation in vitro. Moreover, the regeneration of the vessel wall was detected following implantation and, after six months, the endothelialization of the lumen and the infiltration of arranged smooth muscle cells producing collagen was observed. However, the degradation rate was found to be accelerated in the rabbit animal model. The study was conducted under conditions that reflected the clinical requirements-the prostheses were sutured in the end-to-side fashion and the long-term end point of prosthesis healing was assessed. The regeneration of the vessel wall in terms of endothelialization, smooth cell infiltration and the presence of collagen fibers was observed after six months in vivo. A part of the grafts failed due to the rapid degradation rate of the PLCL copolymer.

Aliphatic Polyester Nanofibers Functionalized with Cyclodextrins and Cyclodextrin-Guest Inclusion Complexes

The fabrication of nanofibers by electrospinning has gained popularity in the past two decades; however, only in this decade, have polymeric nanofibers been functionalized using cyclodextrins (CDs) or their inclusion complexes (ICs). By combining electrospinning of polymers with free CDs, nanofibers can be fabricated that are capable of capturing small molecules, such as wound odors or environmental toxins in water and air. Likewise, combining polymers with cyclodextrin-inclusion complexes (CD-ICs), has shown promise in enhancing or controlling the delivery of small molecule guests, by minor tweaking in the technique utilized in fabricating these nanofibers, for example, by forming core⁻shell or multilayered structures and conventional electrospinning, for controlled and rapid delivery, respectively. In addition to small molecule delivery, the thermomechanical properties of the polymers can be significantly improved, as our group has shown recently, by adding non-stoichiometric inclusion complexes to the polymeric nanofibers. We recently reported and thoroughly characterized the fabrication of polypseudorotaxane (PpR) nanofibers without a polymeric carrier. These PpR nanofibers show unusual rheological and thermomechanical properties, even when the coverage of those polymer chains is relatively sparse (~3%). A key advantage of these PpR nanofibers is the presence of relatively stable hydroxyl groups on the outer surface of the nanofibers, which can subsequently be taken advantage of for bioconjugation, making them suitable for biomedical applications. Although the number of studies in this area is limited, initial results suggest significant potential for bone tissue engineering, and with additional bioconjugation in other areas of tissue engineering. In addition, the behaviors and uses of aliphatic polyester nanofibers functionalized with CDs and CD-ICs are briefly described and summarized. Based on these observations, we attempt to draw conclusions for each of these combinations, and the relationships that exist between their presence and the functional behaviors of their nanofibers.

Preparation of Fish Skin Gelatin-Based Nanofibers Incorporating Cinnamaldehyde by Solution Blow Spinning

Cinnamaldehyde, a natural preservative that can non-specifically deactivate foodborne pathogens, was successfully incorporated into fish skin gelatin (FSG) solutions and blow spun into uniform nanofibers. The effects of cinnamaldehyde ratios (5-30%, w/w FSG) on physicochemical properties of fiber-forming emulsions (FFEs) and their nanofibers were investigated. Higher ratios resulted in higher values in particle size and viscosity of FFEs, as well as higher values in diameter of nanofibers. Loss of cinnamaldehyde was observed during solution blow spinning (SBS) process and cinnamaldehyde was mainly located on the surface of resultant nanofibers. Nanofibers all showed antibacterial activity by direct diffusion and vapor release against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes. Inhibition zones increased as cinnamaldehyde ratio increased. Nanofibers showed larger inhibition effects than films prepared by casting method when S. typhimurium was exposed to the released cinnamaldehyde vapor, although films had higher remaining cinnamaldehyde than nanofibers after preparation. Lower temperature was favorable for cinnamaldehyde retention, and nanofibers added with 10% cinnamaldehyde ratio showed the highest retention over eight-weeks of storage. Results suggest that FSG nanofibers can be prepared by SBS as carriers for antimicrobials.

Immobilization of Platelet-Rich Plasma onto COOH Plasma-Coated PCL Nanofibers Boost Viability and Proliferation of Human Mesenchymal Stem Cells

The scaffolds made of polycaprolactone (PCL) are actively employed in different areas of biology and medicine, especially in tissue engineering. However, the usage of unmodified PCL is significantly restricted by the hydrophobicity of its surface, due to the fact that its inert surface hinders the adhesion of cells and the cell interactions on PCL surface. In this work, the surface of PCL nanofibers is modified by Ar/CO₂/C₂H₄ plasma depositing active COOH groups in the amount of 0.57 at % that were later used for the immobilization of platelet-rich plasma (PRP). The modification of PCL nanofibers significantly enhances the viability and proliferation (by hundred times) of human mesenchymal stem cells, and decreases apoptotic cell death to a normal level. According to X-ray photoelectron spectroscopy (XPS), after immobilization of PRP, up to 10.7 at % of nitrogen was incorporated into the nanofibers surface confirming the grafting of proteins. Active proliferation and sustaining the cell viability on nanofibers with immobilized PRP led to an average number of cells of 258 ± 12.9 and 364 ± 34.5 for nanofibers with ionic and covalent bonding of PRP, respectively. Hence, our new method for the modification of PCL nanofibers with PRP opens new possibilities for its application in tissue engineering.

Hydroxypropyltrimethyl Ammonium Chloride Chitosan Functionalized-PLGA Electrospun Fibrous Membranes as Antibacterial Wound Dressing: In Vitro and In Vivo Evaluation

A novel poly(lactic-co-glycolic acid) (PLGA)-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) composite nanofiber wound dressing was prepared through electrospinning and the entrapment-graft technique as an antibacterial dressing for cutaneous wound healing. HACC with 30% degrees of substitution (DS) was immobilized onto the surface of PLGA membranes via the reaction between carboxyl groups in PLGA after alkali treatment and the reactive groups (⁻NH₂) in HACC molecules. The naked PLGA and chitosan graft PLGA (PLGA-CS) membranes served as controls. The surface immobilization was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and energy dispersive X-ray spectrometry (EDX). The morphology studies showed that the membranes remain uniform after the immobilization process. The effects of the surface modification by HACC and CS on the biological properties of the membranes were also investigated. Compared with PLGA and PLGA-CS, PLGA-HACC exhibited more effective antibacterial activity towards both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacteria. The newly developed fibrous membranes were evaluated in vitro for their cytotoxicity using human dermal fibroblasts (HDFs) and human keratinocytes (HaCaTs) and in vivo using a wound healing mice model. It was revealed that PLGA-HACC fibrous membranes exhibited favorable cytocompatibility and significantly stimulated adhesion, spreading and proliferation of HDFs and HaCaTs. PLGA-HACC exhibited excellent wound healing efficacy, which was confirmed using a full thickness excision wound model in S. aureus-infected mice. The experimental results in this work suggest that PLGA-HACC is a strong candidate for use as a therapeutic biomaterial in the treatment of infected wounds.