Antibacterial electrospun nanofibers from triclosan/cyclodextrin inclusion complexes

Long-Term Antibacterial and Antimildew Polyacrylate-Based TCS@ZIF-8 Leather Coatings Based on Encapsulation and Slow-Release Effects

In this work, we synthesized an acid-responsive zinc metal-organic framework (ZIF-8) at room temperature by a solvent method, which can not only be used as an antibacterial by releasing zinc ions but also as a carrier for antibacterial material encapsulation. Subsequently, the broad-spectrum antibacterial triclosan (TCS) was encapsulated in ZIF-8 by the impregnation method, and a long-term antibacterial and antimildew material with slow-release effect TCS@ZIF-8 was synthesized successfully. The encapsulation rate and drug loading rate of TCS@ZIF-8 prepared by adjusting the mass ratio of ZIF-8 and TCS were 71.9 and 25.1%, respectively. Further, TCS@ZIF-8 was introduced into polyacrylate (PA) emulsion, and PA/TCS@ZIF-8 nanocomposite emulsion was prepared successfully by the physical blending method. When the pH of the coating surface became slightly acidic due to the metabolic byproducts of microbial growth, ZIF-8 in PA/TCS@ZIF-8 disintegrated to release Zn2+ and TCS, which can effectively kill bacteria and mold. When the dosage of TCS was 4.0 wt %, the antibacterial rate of the PA/TCS@ZIF-8 nanocomposite film against Escherichia coli and S. aureus was 100 and 97.3%, respectively. Finally, PA/TCS@ZIF-8 nanocomposite emulsion-coated leather was prepared by the spraying method. Compared with the control group that did not use ZIF-8-encapsulated TCS, PA/TCS@ZIF-8 nanocomposite emulsion-coated leather not only showed better antibacterial and antimildew effects but also showed long-term antibacterial and antimildew performance even after being treated under hot and humid environments of 90% humidity and 40 °C for 30 days. Overall, this study not only provides theoretical guidance into the preparation of long-term antibacterial and antimildew coatings for leather but also has great application prospects in paper, clothing, furniture, and other fields, which has great significance in protecting consumers from the invasion of bacteria and mildew.

Electrospun Nanofibers Incorporated with HPγCD Inclusion Complex for Improved Water Solubility and Activity of Hydrophobic Fungicides Pyrimethanil

The discovery of efficient and stable nanopesticides with improved water solubility and sustained release effects has become particularly important. Pyrimethanil (Pyr) as a low toxicity fungicide of an aniline pyrimidine group is widely used for the prevention and control of gray mold in crops and ornamental plants, however, poor water solubility hinders its further development. Herein, we use a supramolecular self-assembly process to encapsulate a pyrimethanil in a hydroxypropyl-gamma-cyclodextrin (HPγCD) via electrostatic interactions, thereby constructing the inclusion complex nanofibers. The HPγCD as an environmentally friendly carrier material for pesticide delivery is favorable for facilitating the control efficacy, water solubility, and thermostability with Pyr. The diameter of the prepared inclusion nanofiber is 426.6 ± 82.1 nm. Pyr/HPγCD inclusion complex nanofibers could be completely dissolved in water within 3 s. As predicted, the fungicidal activity of Pyr/HPγCD inclusion complex nanofibers is much higher than that of either Pyr, and the EC50 value of Pyr/HPγCD inclusion nanofibers is 0.437 μg/mL, which is about half of that of Pyr (0.840 μg/mL). The inclusion strategy achieved by Pyr and HPγCD is important for improving the safety of nanopesticides. This work provides a versatile insight to promote the development of water-based pesticide dosage forms and reduce pesticide losses in agricultural production.

Polymer-Free Electrospinning of β-Cyclodextrin-Oligolactide for Magnolol and Honokiol Pharmaceutical Formulations

Background: Magnolol (MG) and honokiol (HK) are bioactive compounds extracted from Magnolia obovata and Magnolia Officinalis trees with significant pharmacological properties, including antioxidant and antibacterial activity. However, their poor water solubility and low bioavailability limit the therapeutic potential. Methods: To address these limitations, this study aims to develop MG and HK formulations by co-electrospinning using custom-synthesized β-cyclodextrin-oligolactide (β-CDLA) derivatives. MALDI MS and NMR were employed for the structural assessment of the β-CDLA derivatives. This polymer-free electrospinning technique utilizes the high solubility of β-CDLA to incorporate MG and HK into fibrous webs. The morphology of the resulting fibers is established by SEM and further characterized using FTIR and NMR spectroscopy to confirm the successful incorporation of MG and HK. The antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while the antimicrobial activity was evaluated against several standard microorganisms (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans). Results: The MG and HK electrospun formulations were prepared using highly concentrated feed solutions in dimethylformamide (180% w/v). The resulting β-CDLA fibers, with diameters above 400 nm and an active compound content of 7% wt., exhibited enhanced long-term antioxidant activity and improved antimicrobial efficacy, including notable activity against Escherichia coli. Conclusions: This study demonstrates the potential of MG and HK-loaded β-CDLA fibrous formulations as delivery systems with prolonged antioxidant activity and notable antibacterial efficacy, providing a promising platform for biomedical applications.

Synthesis and Antibacterial Evaluation of Chlorhexidine- and Triclosan-Impregnated Kaolinite Nanocomposites

Clay minerals are actively used to obtain a bioactive composite. Kaolinite, as a representative of clay minerals, possesses unique properties essential for the creation of biocomposite materials. This mineral, characterized by its distinctive layered structure, is chemically inert, highly stable, thermally resistant, eco-friendly, biocompatible, and non-toxic. Kaolinite, which plays the role of a carrier in this work, has such properties and can be the basis for biologically active composites. Antibacterial composites, namely, kaolinite/chlorhexidine and kaolinite/triclosan, were synthesized by impregnation of calcined and non-calcined samples of natural kaolinite with the antibacterial agents chlorhexidine and triclosan. The structure, morphology, elemental composition, and mineralogical characteristics of the natural and synthesized kaolinite/chlorhexidine (KAO/CHX) and kaolinite/triclosan (KAO/TCS) composites were investigated by methods of analysis such as X-ray diffraction, FTIR (Fourier-transform infrared) spectroscopy, and scanning electron microscopy. The calcined kaolinite/chlorhexidine composite at 500 °C (KAO500°C/CHX) exhibited a higher content of antiseptics compared to the non-calcined kaolinite composite. The antibacterial activities of the kaolinite/chlorhexidine and kaolinite/triclosan composites were investigated against Gram-positive Staphylococcus epidermidis and Gram-negative Klebsiella pneumoniae and Escherichia coli strains by the well diffusion method and dilution method. The highest zone of inhibition was observed against Staphylococcus epidermidis (30.00 ± 0.00 mm and 30.67 ± 0.58 mm) by applying KAO/TCS and KAO500°C/TCS via the well diffusion method. The minimum bactericidal concentration of the kaolinite/TCS composite was 15.63 μg/mL for Staphylococcus epidermidis and Klebsiella pneumoniae.

Enrofloxacin Pharmaceutical Formulations through the Polymer-Free Electrospinning of β-Cyclodextrin-oligolactide Derivatives

Enrofloxacin (ENR), a member of the fluoroquinolone class of antibiotics, is widely used in veterinary medicine to treat bacterial infections. Like many antibiotics, ENR has limited water solubility and low bioavailability. To address these challenges, drug formulations using solid dispersions, nanosuspensions, surfactants, cocrystal/salt formation, and inclusion complexes with cyclodextrins may be employed. The approach described herein proposes the development of ENR formulations by co-electrospinning ENR with custom-prepared cyclodextrin-oligolactide (CDLA) derivatives. This method benefits from the high solubility of these derivatives, enabling polymer-free electrospinning. The electrospinning parameters were optimized to incorporate significant amounts of ENR into the CDLA nanofibrous webs, reaching up to 15.6% by weight. The obtained formulations were characterized by FTIR and NMR spectroscopy methods and evaluated for their antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. This study indicates that the presence of CDLA derivative does not inhibit the antibacterial activity of ENR, recommending these formulations for further development.

Photocuring and Gelatin-Based Antibacterial Hydrogel for Skin Care

The development of moisturizing, antibacterial, and biocompatible multifunctional hydrogels is essential to protect skin and promote skin defects recovery. Gelatin has admired potential to be applied for skin care as a hydrogel in virtue of its hydrophilic biocompatible and biodegradable properties. In this study, triclosan-grafted gelatin and photo-cross-linkable methacrylated gelatin were synthesized and then combined to construct the semi-interpenetrating network and antibacterial hydrogels with the aid of a visible blue light. The antimicrobial test demonstrated that the resulting hydrogel obtained excellent inactivation capacity against E. coli, S. aureus, T. rubrum, and C. albicans with sterilizing rates of 99.998%, 99.998%, 99.19%, and 99.64%, respectively. In addition, the cytotoxicity, hemolysis, skin irritation, and rat skin wound healing experiments proved the good biocompatibility of the hydrogel. Therefore, this investigation sheds light on the development of multifunctional hydrogels in skin care.

Advances in Nanotechnology for Biofilm Inhibition

Biofilm-associated infections have emerged as a significant public health challenge due to their persistent nature and increased resistance to conventional treatment methods. The indiscriminate usage of antibiotics has made us susceptible to a range of multidrug-resistant pathogens. These pathogens show reduced susceptibility to antibiotics and increased intracellular survival. However, current methods for treating biofilms, such as smart materials and targeted drug delivery systems, have not been found effective in preventing biofilm formation. To address this challenge, nanotechnology has provided innovative solutions for preventing and treating biofilm formation by clinically relevant pathogens. Recent advances in nanotechnological strategies, including metallic nanoparticles, functionalized metallic nanoparticles, dendrimers, polymeric nanoparticles, cyclodextrin-based delivery, solid lipid nanoparticles, polymer drug conjugates, and liposomes, may provide valuable technological solutions against infectious diseases. Therefore, it is imperative to conduct a comprehensive review to summarize the recent advancements and limitations of advanced nanotechnologies. The present Review encompasses a summary of infectious agents, the mechanisms that lead to biofilm formation, and the impact of pathogens on human health. In a nutshell, this Review offers a comprehensive survey of the advanced nanotechnological solutions for managing infections. A detailed presentation has been made as to how these strategies may improve biofilm control and prevent infections. The key objective of this Review is to summarize the mechanisms, applications, and prospects of advanced nanotechnologies to provide a better understanding of their impact on biofilm formation by clinically relevant pathogens.

Antibacterial Capability of Air Filter Fiber Materials Treated with Triclosan against Indoor Environmental Microbes

Antibacterial filtration materials have been used effectively to control biological pollutants and purify indoor air. This study aimed to assess the antibacterial capability of three fiber filter materials treated with triclosan: glass fiber (GF), non-woven fabric (NF) and chemical fiber (CF). Triclosan was loaded onto the filtration materials by the impregnation method. The triclosan-treated filter materials exhibited antibacterial zones obviously: the average antibacterial bands against E. coli were 11.8 mm (GF), 13.3 mm (NF) and 10.5 mm (CF); against S. albus, they were 25.5 mm (GF), 21.0 mm (NF) and 23.5 mm (CF). The percent reductions of bacteria for the antibacterial air fiber materials treated with triclosan against E. coli were 71.4% (CF) and 62.6% (GF), while the percent reductions against S. albus were 61.3% (NF) and 84.6% (CF). These findings could help to reduce the transmission and threat of epidemic and purify the environment through the use of environmentally friendly antibacterial filter fibers.

Electrospun Nanofibers Revisited: An Update on the Emerging Applications in Nanomedicine

Electrospinning (ES) has become a straightforward and customizable drug delivery technique for fabricating drug-loaded nanofibers (NFs) using various biodegradable and non-biodegradable polymers. One of NF's pros is to provide a controlled drug release through managing the NF structure by changing the spinneret type and nature of the used polymer. Electrospun NFs are employed as implants in several applications including, cancer therapy, microbial infections, and regenerative medicine. These implants facilitate a unique local delivery of chemotherapy because of their high loading capability, wide surface area, and cost-effectiveness. Multi-drug combination, magnetic, thermal, and gene therapies are promising strategies for improving chemotherapeutic efficiency. In addition, implants are recognized as an effective antimicrobial drug delivery system overriding drawbacks of traditional antibiotic administration routes such as their bioavailability and dosage levels. Recently, a sophisticated strategy has emerged for wound healing by producing biomimetic nanofibrous materials with clinically relevant properties and desirable loading capability with regenerative agents. Electrospun NFs have proposed unique solutions, including pelvic organ prolapse treatment, viable alternatives to surgical operations, and dental tissue regeneration. Conventional ES setups include difficult-assembled mega-sized equipment producing bulky matrices with inadequate stability and storage. Lately, there has become an increasing need for portable ES devices using completely available off-shelf materials to yield highly-efficient NFs for dressing wounds and rapid hemostasis. This review covers recent updates on electrospun NFs in nanomedicine applications. ES of biopolymers and drugs is discussed regarding their current scope and future outlook.

Application of essential oils in packaging films for the preservation of fruits and vegetables: A review

Fruits and vegetables are highly perishable in nature. Several factors could affect the quality and shelf life of fruits and vegetables. Packaging materials (usually made up of polymers, proteins, lipids, polysaccharides, etc.,) are incorporated with essential oil (EO) which is high in antimicrobial and antioxidant compounds that can enhance the shelf life of fruits and vegetables without affecting their quality. However, the use of EO for postharvest preservation can alter the organoleptic properties of fresh produce. Exploiting synergistic interactions between several EOs, encapsulation of EO, or combining EO with non-thermal techniques such as irradiation, UV-C, cold plasma, ultrasound, etc., may help in preventing the spoilage of food products at lower concentrations without altering their organoleptic properties. This review aims to discuss the overview and current scenario of packaging film with EO for the preservation of fruit and vegetables. We have also discussed the spoilage mechanism of fruits and vegetables, mode of action of EOs, and the effect of EO with packaging film on antimicrobial and sensory properties of fruits and vegetables.

Enhanced stability and controlled release of menthol using a β-cyclodextrin metal-organic framework

Menthol inclusion complexes (ICs) have addressed a range of opportunities in food applications due to their volatile resistance. However, previous protocols used for their synthesis give low yields and high industrial application costs. In the present investigation, metal-organic frameworks based on β-cyclodextrin (β-CD-MOF) have been prepared for the molecular encapsulation of menthol. Menthol/β-CD-MOF-IC was synthesized under the optimized parameters, after which release behavior was studied. In this optimized manner, a higher menthol capacity was obtained in which the menthol content and encapsulation efficiency were 27.1 and 30.6%, respectively. Compared with menthol/β-CD-IC, menthol/β-CD-MOF-IC is resistant to high temperature, but sensitive to moisture. In a simulated oral release experiment, the rate of menthol release from different samples followed the order of: pure menthol > β-CD > β-CD-MOF, which can be attributed to two mechanisms: non-specific binding and site preference. We propose that β-CD-MOF can be used as a promising delivery system for aroma compounds.

Recent developments in polysaccharide-based electrospun nanofibers for environmental applications

Electrospinning has become an inevitable approach to produce nanofibrous structures for diverse environmental applications. Polysaccharides, due to their variety of types, biobased origins, and eco-friendly, and renewable nature are wonderful materials for the said purpose. The present review discusses the electrospinning process, the parameters involved in the formation of electrospun nanofibers in general, and the polysaccharides in specific. The selection of materials to be electrospun depends on the processing conditions and properties deemed desirable for specific applications. Thereby, the conditions to electrospun polysaccharides-based nanofibers have been focused on for possible environmental applications including air filtration, water treatment, antimicrobial treatment, environmental sensing, and so forth. The polysaccharide-based electrospun membranes, for instance, due to their active adsorption sites could find significant potential for contaminants removal from the aqueous systems. The study also gives some recommendations to overcome any shortcomings faced during the electrospinning and environmental applications of polysaccharide-based matrices.

Physicochemical compatibility studies of triclosan and flurbiprofen with excipients of pharmaceutical formulation using binary, ternary, and multi-combination approach

Background

The aim of the study was to evaluate the suitability of triclosan (TCS) and flurbiprofen (FLB) with poly-ε-caprolactone (PCL), chitosan (CS), and Kolliphor® P188 (KP) for possible application in the design of nano-formulations.

Results

Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) revealed the physical characteristics of the various sample compositions without any apparent interaction. The Fourier transform infrared spectroscopy (FTIR)’s spectra of the physical mixtures showed their characteristic absorption bands with broadening and overlapping of bands in some instances, but no appearance of new bands was observed.

Conclusion

The study revealed the physical form stability of the evaluated components after the storage period and lack of definite pharmaceutical incompatibility between them. Thus, the selected drugs and excipients could be used for the development of pharmaceutical nano-formulations.

Advances in Fabricating the Electrospun Biopolymer-Based Biomaterials

Biopolymers formed into a fibrous morphology through electrospinning are of increasing interest in the field of biomedicine due to their intrinsic biocompatibility and biodegradability and their ability to be biomimetic to various fibrous structures present in animal tissues. However, their mechanical properties are often unsatisfactory and their processing may be troublesome. Thus, extensive research interest is focused on improving these qualities. This review article presents the selection of the recent advances in techniques aimed to improve the electrospinnability of various biopolymers (polysaccharides, polynucleotides, peptides, and phospholipids). The electrospinning of single materials, and the variety of co-polymers, with and without additives, is covered. Additionally, various crosslinking strategies are presented. Examples of cytocompatibility, biocompatibility, and antimicrobial properties are analyzed. Special attention is given to whey protein isolate as an example of a novel, promising, green material with good potential in the field of biomedicine. This review ends with a brief summary and outlook for the biomedical applicability of electrospinnable biopolymers.

Prospects of Polymeric Nanofibers Loaded with Essential Oils for Biomedical and Food-Packaging Applications

Essential oils prevent superbug formation, which is mainly caused by the continuous use of synthetic drugs. This is a significant threat to health, the environment, and food safety. Plant extracts in the form of essential oils are good enough to destroy pests and fight bacterial infections in animals and humans. In this review article, different essential oils containing polymeric nanofibers fabricated by electrospinning are reviewed. These nanofibers containing essential oils have shown applications in biomedical applications and as food-packaging materials. This approach of delivering essential oils in nanoformulations has attracted considerable attention in the scientific community due to its low price, a considerable ratio of surface area to volume, versatility, and high yield. It is observed that the resulting nanofibers possess antimicrobial, anti-inflammatory, and antioxidant properties. Therefore, they can reduce the use of toxic synthetic drugs that are utilized in the cosmetics, medicine, and food industries. These nanofibers increase barrier properties against light, oxygen, and heat, thereby protecting and preserving the food from oxidative damage. Moreover, the nanofibers discussed are introduced with naturally derived chemical compounds in a controlled manner, which simultaneously prevents their degradation. The nanofibers loaded with different essential oils demonstrate an ability to increase the shelf-life of various food products while using them as active packaging materials.

Polymer-free cyclodextrin and natural polymer-cyclodextrin electrospun nanofibers: A comprehensive review on current applications and future perspectives

The present review discusses the use of cyclodextrins and their derivatives to prepare electrospun nanofibers with specific features. Cyclodextrins, owing to their unique capability to form inclusion complexes with hydrophobic and volatile molecules, can indeed facilitate the encapsulation of bioactive compounds in electrospun nanofibers allowing fast-dissolving products for food, biomedical, and pharmaceutical purposes, filtering materials for wastewater and air purification, as well as a variety of other technological applications. Additionally, cyclodextrins can improve the processability of naturally occurring biopolymers helping the fabrication of "green" materials with a strong industrial relevance. Hence, this review provides a comprehensive state-of-the-art of different cyclodextrins-based nanofibers including those made of pure cyclodextrins, of polycyclodextrins, and those made of natural biopolymer functionalized with cyclodextrins. To this end, the advantages and disadvantages of such approaches and their possible applications are investigated along with the current limitations in the exploitation of electrospinning at the industrial level.

Fast-dissolving antibacterial nanofibers of cyclodextrin/antibiotic inclusion complexes for oral drug delivery

HYPOTHESIS

The widespread use of antibacterial electrospun nanofibers is mostly restricted due to their low loading capacity to carry antibiotics and the need to use toxic organic solvents to boost the antibiotic loading capacity. Nanofibers based on natural excipients, such as cyclodextrin (CD)-based nanofibers, can carry larger amounts of antibiotics while achieving better stability via inclusion complexation.

EXPERIMENTS

Nanofibers were produced by electrospinning and analyzed by electron microscopy to investigate the morphology of fibers. The formation of inclusion-complexation was analyzed by ¹H NMR, FTIR, and XRD. Thermal analysis of the fibers was done using TGA. Ab initio modeling studies were done to calculate the complexation energies of antibiotics with CD. A disk-diffusion assay was used to test the antibacterial activity of the fibers.

FINDINGS

Bead-free antibacterial nanofibers with mean diameters between 340 and 550 nm were produced. The formation of inclusion complexes (IC) between the CD and the antibiotics was confirmed by FTIR and ¹H NMR, which was further verified by the disappearance of the crystalline peaks of antibiotics as determined by XRD analysis. Thermal analysis of the nanofibers revealed that the formulations showed good antibiotic encapsulation (45-90%). Ab initio simulations revealed that gentamicin had the highest complexation energy, followed by kanamycin, chloramphenicol, and ampicillin. The antibacterial nanofibers rapidly dissolved in water and artificial saliva, successfully releasing the CD antibiotic complexes. The nanofibers showed high antibacterial activity against Gram-negative Escherichia coli.

Progress in the design and development of "fast-dissolving" electrospun nanofibers based drug delivery systems - A systematic review

Electrospinning has emerged as most viable approach for the fabrication of nanofibers with several beneficial features that are essential to various applications ranging from environment to biomedicine. The electrospun nanofiber based drug delivery systems have shown tremendous advancements over the controlled and sustained release complemented from their high surface area, tunable porosity, mechanical endurance, offer compatible environment for drug encapsulation, biocompatibility, high drug loading and tailorable release characteristics. The dosage formulation of poorly water-soluble drugs often faces several challenges including complete dissolution with maximum therapeutic efficiency over a short period of time especially through oral administration. In this context, challenges associated with the dosage formulation of poorly-water soluble drugs can be addressed through combining the beneficial features of electrospun nanofibers. This review describes major developments progressed in the preparation of electrospun nanofibers based "fast dissolving" drug delivery systems by employing variety of polymers, drug molecules and encapsulation approaches with primary focus on oral delivery. Furthermore, the review also highlights current scientific challenges and provide an outlook with regard to future prospectus.

Development of natural polymeric microcapsules for antimicrobial drug delivery: triclosan loaded chitosan and alginate-based microcapsules

The goal of this work was the development of natural polymeric microcapsules for antimicrobial drug delivery - triclosan loaded alginate and chitosan-based microcapsules for potential coating applications in substrates such as textiles or plastics. Microcapsules containing 2.5% (w/w) or 3% (w/w) triclosan in both core and matrix were synthesized and evaluated by Fourier-transform infrared spectroscopy, scanning electron microscopy, confocal microscopy, differential scanning calorimetry, thermogravimetry, and antimicrobial activity. The microcapsules produced featured spherical and mostly irregularly-shaped surfaces composed by an alginate core in a chitosan outer matrix, as revealed by confocal microscopy, and antimicrobial activity against S. aureus and E. coli with inhibition halos up to 60 mm and 25 mm respectively, granted by a triclosan loading of 61.66%. The thermal analysis suggested that the polymers protected the active substance from temperature-induced degradation. In conclusion, these microcapsules may be applied toward antimicrobial functionalization of plastics, textiles and other materials.

Bioactive bacterial cellulose membrane with prolonged release of chlorhexidine for dental medical application

Bioabsorbable barrier membrane is desired in dental medicine for treatment of periodontal diseases caused by different types of bacteria. Bioactive and bioabsorbable bacterial cellulose (BC) is a promising material for such application. However, a key challenge to implement this approach is produce BC membranes selectively oxidized and loaded with a bactericide, in order to modulate bioabsortion time and bactericide effect, respectively. In the present study, the drug model chlorhexidine (CHX) was chosen and NaIO₄ was used as oxidizing agent. To modulate CHX release and efficacy, inclusion complexes of CHX with β-cyclodextrin (CHX:βCD) were synthesized. A linear dependence between degree of oxidation (DO) and oxidant concentration was found (DO = 2.07 + 45 [NaIO₄]). CHX has strong chemical interaction with cellulose structure, contributing for its significant retention. The association of membrane oxidation and formation of the inclusion complex with βCD causes a 10-fold increase in CHX release rate compared to unmodified cellulose. Thus, validating the concept that CHX release can be modulated using these two strategies. All membranes loaded with CHX inhibited S. aureus, E. coli and C. albicans growth, but DABC+CHX:βCD showed greater inhibition zone (p < 0.05). That, associated with other results, indicates potential application as bioactive and bioabsorbable membrane.

Electrospun nanofibers as versatile platform in antimicrobial delivery: current state and perspectives

Nanotechnology has attracted increasing interest in different aspects of biotechnology. The fabrication of electrospun nanofibers (NFs) containing antibacterial agents for antimicrobial applications has been significantly enhanced in recent years. In the current review, various electrospun NFs with antimicrobial properties were introduced and evaluated. The main focus was on the recent developments and applications of antimicrobial electrospun NFs incorporated with different antimicrobial agents, including metal nanoparticles (NPs), antibiotics, quaternized ammonium compounds, triclosan, herbal extracts, carbon nanomaterials, and antimicrobial biopolymers with inherent antimicrobial properties. The search results revealed that antimicrobial containing electrospun NFs had enhanced antimicrobial performance with various biomedical applications compared to the traditional antimicrobial materials. According to the reported results, most of the studies were of an investigative nature and were mostly based on in vitro tests. Hence, further examination on in vivo clinical performance of these antimicrobial NFs seems necessary. However, these antimicrobial NFs appear to have the potential to achieve clinical usefulness and commercial production in the near future.

A dual-action chitosan-based nanogel system of triclosan and flurbiprofen for localised treatment of periodontitis

This study aimed to develop a dual action, namely anti-inflammatory and antimicrobial, nanogels (NG) for the treatment of periodontitis using triclosan (TCS) and flurbiprofen (FLB). Triclosan, an antimicrobial drug, was prepared as nanoparticles (NPs) using poly-ε-caprolactone (PCL), while flurbiprofen, an anti-inflammatory drug, was directly loaded in a chitosan (CS) based hydrogel. The entwinement of both NPs and hydrogel loaded systems resulted in the NG. The characterisation data confirmed that the developed formulation consists of nanosized spherical structures and displays pH-dependent swelling/erosion and temperature-responsiveness. Besides, the NG exhibited adequate bioadhesiveness using the chicken pouch model and displayed antibacterial activity through the agar plate method. An in-vivo study of the NG on experimental periodontitis (EP) rats confirmed the dual antibacterial and anti-inflammatory effects which revealed an excellent therapeutic outcome. In conclusion, a dual action NG was successfully developed and proved to have superior therapeutic effects in comparison to physical mixtures of the individual drugs.

Development of polyvinyl alcohol/β-cyclodextrin antimicrobial nanofibers for fresh mushroom packaging

Under the optimal conditions, a crosslinked electrospun polyvinyl alcohol/cinnamon essential oil/β-cyclodextrin (CPVA-CEO-β-CD) nanofibrous films for sustained release of antimicrobials were successfully prepared. Cinnamon essential oil (CEO) can be sustainably released due to CPVA-CEO-β-CD nanofibers complex delivery systems. The chemical crosslinking and physical welding achieved simultaneously by glutaraldehyde atomization fumigation, making fibers more suitable for fresh food packaging. Nanofibrous films were characterized in terms of SEM, ATR-FTIR, DSC, water contact angle analysis and antibacterial trials. ATR-FTIR and DSC data indicated that CEO was encapsulated in a β-CD cavity and they coexisted in PVA nanofibers. The water contact angle of the crosslinked PVA nanofibrous films increased with CEO and the values were always below 90°. Crosslinked nanofibers possessed fine properties in vitro antibacterial against Staphylococcus aureus and Escherichia coli. Furthermore, CPVA/β-CD/CEO nanofibrous films delayed decay of mushroom during storage, indicating their potential implementation in active food packaging.

β-Cyclodextrin based air filter for high-efficiency filtration of pollution sources

Airborne particulate matter (PM) pollution has become a serious environmental problem. Thus, there is a need for the development of air filters with satisfactory overall performance. In this paper, we develop a kind of β-cyclodextrin (β-CD) based air filter with high strength, which has not only high filtration efficiency (about 99%) but also good air permeability (the pressure drop is only 45Pa). Especially after long-term application, the pression drop of β-cyclodextrin based was less than half of the commercial air-filter. Additionally, the material can capture the toxic gasous chemicals (e.g. formaldehyde and SO₂). The introduction of β-CD is supposed to be the key factor for improvement of air filter.

Electrochemical sensor based on molecularly imprinted polymer for sensitive triclosan detection in wastewater and mineral water

Triclosan (TCS) is a topical antiseptic widely used in different cosmetic products. It is also a common additive in many antimicrobial household consumables. Over a certain concentration, it becomes risky for human and environmental health. This work describes the development of an electrochemical sensor based on molecularly imprinted polymer (MIP), assembled on screen-printed gold electrode (Au-SPE), dedicated to the TCS detection in environmental water sources. To achieve this goal, an acrylamide/bisacrylamide solution was polymerized after linking TCS with the carboxylic polyvinyl chloride (PVC-COOH) layer onto the Au-SPE. The sensor device fabrication and its retention capabilities were characterized through cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. As control experiment, negligible responses were obtained during the non-imprinted polymer (NIP) test. The sensor could effectively detect TCS avoiding interferences of structural similar substances like 2,4,6-trichlorophenol and catechol. Under optimal conditions, the sensor responses were found logarithmic in the concentration range from 0.1 to 1000 pg mL^-1. Indeed, compared with reported works, this sensor exhibits lower detection limit (LOD) and quantification limit (LOQ) of 0.23 and 0.78 pg mL^-1, respectively. The developed sensor was effectively applied to wastewater samples for TCS detection and displayed satisfactory performances. Moreover, the different wastewater samples, regarding their TCS contents, were correctly classified by using principal component analysis (PCA) technique. Correspondingly, this work has demonstrated a cheap, simple and effective sensing platform for TCS detection thus making it a promising tool for future evolution of accurate and reliable environmental analysis.

Functional characteristics of Bambara groundnut starch-catechin complex formed using cyclodextrins as initiators

Bambara groundnut (BGN) starch extracted from BGN flour was modified through complexation methods using alpha and beta cyclodextrin. Complexation methods used included the microwave, co-evaporation and kneading methods. Cyclodextrin (alpha and beta) were used as initiators for grafting catechin to the BGN starch molecule. The functional properties of native and modified BGN starches were assessed. The swelling capacity of BGN starches increased with an increase in temperature. The swelling capacities of BGN starches ranged from 0.36 g/g (BGN starch modified through the co-evaporation method, beta cyclodextrin + catechin) to 4.84 g/g (BGN starch modified through the microwave method, beta cyclodextrin + catechin). Complexation methods significantly reduced the swelling capacity of native BGN starch. Temperatures had a significant (p ≤ 0.05) effect on the swelling capacity of BGN starches. The solubility of BGN starches ranged from 0.61 g/100 g (native BGN starch) to 46.04 g/100 g (BGN starch modified through the kneading method, alpha cyclodextrin); using water as a solvent. The water absorption of native and modified BGN starches ranged from 0.23 to 1.17 g/g, respectively. Starches complexed with β-cyclodextrin showed increased water absorption capacity in comparison to the starches complexed with alpha cyclodextrin. The modification methods had a significant (p ≤ 0.05) effect on the water absorption capacities of BGN starches. There was no significant difference in the oil absorption capacities of BGN starches and they ranged from 1.02 to 1.07 g/g. Pasting properties of BGN starches were assessed using a rapid visco analyser (RVA). The modified starches exhibited lower breakdown, setback, and final viscosities as well as significant increase in gelatinisation temperature compared to the native BGN starch.

Dual-functional core-shell electrospun mats with precisely controlled release of anti-inflammatory and anti-bacterial agents

Acute wounds are worldwide problems affecting millions of people and causing heavy economic burden to national healthcare systems. Herein, we describe novel wound dressing materials relying on core/shell electrospun mats incorporated with flurbiprofen and vancomycin for achieving programmable release of anti-inflammatory and anti-bacterial agents. The shell matrix of nanofibers consisted of polyethylene oxide while the core matrix was made from a blend of silk and collagen. Several optimal mat architectures were engineered with distinct configurations, of which release profiles displayed an exponential trend, which indicates a first-order process following Fickian diffusion behavior. The flurbiprofen release lasted from 2 to 6 days, which was much faster compared to the one of vancomycin prolonged up to about 20 days. Mechanical data indicated tensile modulus, tensile strength, elongation before break of core/shell electrospun mats became enhanced or comparable to those for human skin after methanol vapor treatment. Desirable release kinetics and mechanical characteristics achieved by novel core/shell electrospun mats were attributable to induced enrichment of β-sheet phase in silk via methanol vapor treatment as well as water annealing process with time and judicious selections for matrix materials and mat configurations. The design principles considered in this study successfully addressed a range of inflammation and infection requirements in wound healing, potentially guiding construction of other biomedical coatings and devices.

Advances of nanosystems containing cyclodextrins and their applications in pharmaceuticals

For many years, researchers have worked with supramolecular structures involving inclusion complexes with cyclodextrins. These studies have resulted in new commercially available drugs which have been of great benefit. More recently, studies using nanoparticles, including nanosystems containing cyclodextrins, have become a focus of academic research due to the versatility of the systems and their remarkable therapeutic potential. This review focuses on studies published between 2002 and 2018 involving nanosystems containing cyclodextrins. We consider the type of nanosystems, their importance in a health context, the physicochemical techniques used to show the quality of these systems and their potential for the development of novel pharmaceutical formulations. These have been developed in recent studies which have mainly been focusing on basic science with no clinical trials as yet being performed. This is important to note because it means that the studies do not include any toxicity tests. Despite this limitation, the characterization assays performed suggest that these new formulations may have therapeutic potential. However, more research is required to assess the efficacy and safety of these nanosystems.

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.

Active Food Packaging Coatings Based on Hybrid Electrospun Gliadin Nanofibers Containing Ferulic Acid/Hydroxypropyl-Beta-Cyclodextrin Inclusion Complexes

In this work, hybrid gliadin electrospun fibers containing inclusion complexes of ferulic acid (FA) with hydroxypropyl-beta-cyclodextrins (FA/HP-β-CD-IC) were prepared as a strategy to increase the stability and solubility of the antioxidant FA. Inclusion complex formation between FA and HP-β-CD was confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD). After adjusting the electrospinning conditions, beaded-free fibers of gliadin incorporating FA/HP-β-CD-IC with average fiber diameters ranging from 269.91 ± 73.53 to 271.68 ± 72.76 nm were obtained. Control gliadin fibers containing free FA were also produced for comparison purposes. The incorporation of FA within the cyclodextrin molecules resulted in increased thermal stability of the antioxidant compound. Moreover, formation of the inclusion complexes also enhanced the FA photostability, as after exposing the electrospun fibers to UV light during 60 min, photodegradation of the compound was reduced in more than 30%. Moreover, a slower degradation rate was also observed when compared to the fibers containing the free FA. Results from the release into two food simulants (ethanol 10% and acetic acid 3%) and PBS also demonstrated that the formation of the inclusion complexes successfully resulted in improved solubility, as reflected from the faster and greater release of the compounds in the three assayed media. Moreover, in both types of hybrid fibers, the antioxidant capacity of FA was kept, thus confirming the suitability of electrospinning for the encapsulation of sensitive compounds, giving raise to nanostructures with potential as active packaging structures or delivery systems of use in pharmaceutical or biomedical applications.