Microencapsulation of lime (Citrus aurantifolia) oil for antibacterial finishing of cotton fabric

An optimized chitosan/alginate-based microencapsulation of lime peel essential oil and its application as an antibacterial textile

A functional textile immobilized by microcapsules of the lime peel essential oils of C. aurantifolia (LPEO) was prepared and characterized. A varied amount of Chitosan/Alginate (CH/AG) ratios, followed by a mass of LPEO and concentration of sodium tripolyphosphate (STPP) crosslinker, was optimized sequentially to coacervate LPEO using a Tween 80 emulsifier. An antibacterial assay against both Gram-positive and Gram-negative bacteria was further evaluated for the embedded microcapsules. The LPEO (0.2 g) was effectively coacervated by CH/AG (5:3) crosslinked by 2% of STTP to give a yield, oil content (OC), and encapsulation efficiency (EE) of 53.45 ± 2.16%, 65.08 ± 2.60% and 85.04 ± 0.70% respectively. A rough spherical shape of LPEO microcapsules was homogeneously observed with an average particle size of 0.757 mm. An Avrami's kinetic model revealed the release mechanism of the core following zero-order kinetics (k = 1.11 ± 0.13 × 10-9 s-1, Ea = 70.21 kJ/mol). The LPEO microcapsules demonstrated good thermal stability up to 122 °C and maintained 38% OC at ambient temperature for four weeks. A 70.34 ± 4.16% of the LPEO microcapsules were successfully overlaid onto the gauze with citric acid binder and sodium phosphate catalyst. Overall, the immobilized microcapsules exhibited strong inhibition against S. aureus and moderate against S. epidermidis, E. coli, and K. pneumonia.

Mechanochemical Encapsulation of Caffeine in UiO-66 and UiO-66-NH2 to Obtain Polymeric Composites by Extrusion with Recycled Polyamide 6 or Polylactic Acid Biopolymer

The development of capsules with additives that can be added to polymers during extrusion processing can lead to advances in the manufacturing of textile fabrics with improved and durable properties. In this work, caffeine (CAF), which has anti-cellulite properties, has been encapsulated by liquid-assisted milling in zirconium-based metal-organic frameworks (MOFs) with different textural properties and chemical functionalization: commercial UiO-66, UiO-66 synthesized without solvents, and UiO-66-NH2 synthesized in ethanol. The CAF@MOF capsules obtained through the grinding procedure have been added during the extrusion process to recycled polyamide 6 (PA6) and to a biopolymer based on polylactic acid (PLA) to obtain a load of approximately 2.5 wt% of caffeine. The materials have been characterized by various techniques (XRD, NMR, TGA, FTIR, nitrogen sorption, UV-vis, SEM, and TEM) that confirm the caffeine encapsulation, the preservation of caffeine during the extrusion process, and the good contact between the polymer and the MOF. Studies of the capsules and PA6 polymer+capsules composites have shown that release is slower when caffeine is encapsulated than when it is free, and the textural properties of UiO-66 influence the release more prominently than the NH2 group. However, an interaction is established between the biopolymer PLA and caffeine that delays the release of the additive.

Boric acid crosslinked chitosan microcapsules loaded with frankincense oil for the development of mosquito-repellent, antibacterial, antioxidant, and flame-retardant cotton

In ancient times, textiles were only used for covering the human body. Nowadays, people are looking for functional textiles to provide additional functional properties. In the present work, an attempt was made to develop chitosan and boric acid-based microcapsules loaded with frankincense oil. Application of these microcapsules was done on cotton using a pad-dry method. The release rate, encapsulation efficiency and microencapsulation yield of microcapsules, and functional properties of finished fabric were studied. The prepared microcapsules were also characterised by different techniques like SEM, FTIR, TGA, and EDX. The finished fabric exhibited mosquito repellency (100 %), antioxidant activity (>66 %), antibacterial activity against E. coli (88.69 %) and S. aureus (94.5 %), and LOI of 24 with a pleasant aroma.

Bioactive Components and Their Activities from Different Parts of Citrus aurantifolia (Christm.) Swingle for Food Development

Citrus aurantifolia is part of the Rutaceae family and belongs to the genus Citrus. It is widely used in food, the chemical industry, and pharmaceuticals because it has a unique flavor and odor. It is nutrient-rich and is beneficial as an antibacterial, anticancer, antioxidant, anti-inflammatory, and insecticide. Secondary metabolites present in C. aurantifolia are what give rise to biological action. Flavonoids, terpenoids, phenolics, limonoids, alkaloids, and essential oils are among the secondary metabolites/phytochemicals discovered in C. aurantifolia. Every portion of the plant's C. aurantifolia has a different composition of secondary metabolites. Environmental conditions such as light and temperature affect the oxidative stability of the secondary metabolites from C. aurantifolia. The oxidative stability has been increased by using microencapsulation. The advantages of microencapsulation are control of the release, solubilization, and protection of the bioactive component. Therefore, the chemical makeup and biological functions of the various plant components of C. aurantifolia must be investigated. The aim of this review is to discuss the bioactive components of C. aurantifolia such as essential oils, flavonoids, terpenoids, phenolic, limonoids, and alkaloids obtained from different parts of the plants and their biological activities such as being antibacterial, antioxidant, anticancer, an insecticide, and anti-inflammatory. In addition, various extraction techniques of the compounds out of different parts of the plant matrix as well as the microencapsulation of the bioactive components in food are also provided.

Water-resistant antibacterial properties of a graphene oxide/cetylpyridinium chloride complex formed on medical gauze fibers

OBJECTIVES

Graphene oxide (GO) is a nanocarbon material with a high aspect ratio (width:thickness) and abundant anionic functional groups on its surface. In this study, we attached GO to the surface of medical gauze fibers, constructed a complex with a cationic surface active agent (CSAA), and demonstrated that the treated gauze exhibits antibacterial activity even after rinsing with water.

METHODS

Medical gauze was immersed in GO dispersion (0.001%, 0.01%, and 0.1%), rinsed with water, dried, and subjected to the Raman spectroscopy analysis. Subsequently, the gauze treated with 0.001% GO dispersion was immersed in 0.1% cetylpyridinium chloride (CPC) solution, immediately rinsed with water, and dried. Untreated, GO-only, and CPC-only gauzes were prepared for comparison. Each gauze was placed in a culture well, seeded with Escherichia coli or Actinomyces naeslundii, and turbidity was measured after 24 h of incubation.

RESULTS

The Raman spectroscopy analysis of the gauze after immersion and rinsing showed a G-band peak, indicating that GO remained on the surface of the gauze. The turbidity measurements indicated that GO/CPC-treated gauze (GO-treated and rinsed, followed by CPC-treatment and rinsing) significantly decreased turbidity compared to the other gauzes (P<0.05), suggesting that the GO/CPC complex remained on the gauze fibers even after water rinsing and showed antibacterial activity.

CONCLUSIONS

The GO/CPC complex imparts water-resistant antibacterial properties to gauze and has the potential to be widely used for the antimicrobial treatment of clothes.

The Development of the Antibacterial Microcapsules of Citrus Essential Oil for the Cosmetotextile Application: A Review

Essential oils (EOs) obtained from the Citrus genus were reported to exhibit good antimicrobial activity. Therefore, they can potentially be applied in daily necessities such as textile sectors as antibacterial functional fabric products. However, a packaging technique to retain such volatile and labile active substances is compulsory. In particular, microencapsulation was found to be a common coating technique employed to protect EOs from the effects of light, heat, humidity, stability, and controlled release of active substances. Various microencapsulation techniques have been introduced, but the most widely used method is complex coacervation, as it is simple, inexpensive, and capable of snaring high essential oils. Hence, this review focused on the microencapsulation of the most consumable citrus EOs with complex coacervation methods and their immobilization on commonly carried-out fabrics. In addition, it also discusses the isolation methods of the EOs, their chemical composition, and the mechanism of antibacterial action.

Silver Thread-Based Microfluidic Platform for Detection of Essential Oils Using Impedance Spectroscopy

Essential oils (EOs) have a long tradition of use in the medical and cosmetic fields based on their versatile properties, including fungicidal, antiparasitic, and bactericidal effects. Nowadays, with the development of industry and electronics, EOs are increasingly being used in the agricultural and food industries; health industries, including pharmacy and dental medicine; and as cosmetic enhancements. The purpose of this study is to develop a compact and portable platform for the detection of EO type and the concentration levels using knitted silver threads. The method is based on measuring the variation in values of the electrical parameters of the silver threads using electrochemical impedance spectroscopy (EIS). The impedance of the solutions applied on the testing platform was measured in the frequency range from 1 Hz to 200 kHz. The platform was tested using three types of essential oils: tea tree; clary sage; and cinnamon bark oil. Increasing the concentration of essential oils resulted in increasing the electrical resistance of the platform, decreasing the capacitance, and consequently increasing the impedance. The proposed cost-effective platform can be used for the fast determination of the type and quality of essential oils.

Microencapsulation of Citrus aurantifolia essential oil with the optimized CaCl2 crosslinker and its antibacterial study for cosmetic textiles†

A functional fabric immobilized by the microcapsules of C. aurantifolia lime essential oil (LO) was prepared and characterized. A varied amount of CaCl₂ crosslinker was optimized to coacervate LO using alginate–gelatin biopolymers and Tween 80 emulsifier. A further evaluation of the immobilized LO microcapsules for the antibacterial effect against both Gram-positive and Gram-negative bacteria was conducted. The optimized alginate/gelatin-based microcapsules were effectively crosslinked by 15% CaCl₂ with an yield, oil content (OC), and encapsulation efficiency (EE) of 39.91 ± 3.10%, 78.33 ± 7.53%, and 90.27 ± 5.84%, respectively. A spherical shape of LO microcapsules was homogeneously found with an average particle size of 1.394 μm. A first-order kinetics mechanism for the release of LO out of the microcapsules was modeled by Avrami's kinetic equation (k = 1.60 ± 3.68 × 10⁻⁵ s⁻¹). The LO microcapsules demonstrated good thermal stability up to 100 °C and maintained 51.07% OC and 43.56% EE at ambient temperature for three weeks. Using a pad dry method and citric acid binder, LO microcapsules were successfully immobilized on a cloth with a % add on 30.60 ± 1.80%. The LO microcapsules and the immobilized one exhibited a moderate ZoI of bacterial growth for Gram-positive S. aureus and S. epidermidis as well as Gram-negative E. coli and K. pneumonia. Further washing test toward the functional fabric showed that the LO microcapsules incorporated into the fabric were resistant to five cycles of normal washing with a mass reduction of 22.01 ± 1.69%.

A functional fabric immobilized by the microcapsules of C. aurantifolia lime essential oil (LO) was prepared and characterized.

Microencapsulation for Functional Textile Coatings with Emphasis on Biodegradability—A Systematic Review

The review provides an overview of research findings on microencapsulation for functional textile coatings. Methods for the preparation of microcapsules in textiles include in situ and interfacial polymerization, simple and complex coacervation, molecular inclusion and solvent evaporation from emulsions. Binders play a crucial role in coating formulations. Acrylic and polyurethane binders are commonly used in textile finishing, while organic acids and catalysts can be used for chemical grafting as crosslinkers between microcapsules and cotton fibres. Most of the conventional coating processes can be used for microcapsule-containing coatings, provided that the properties of the microcapsules are appropriate. There are standardised test methods available to evaluate the characteristics and washfastness of coated textiles. Among the functional textiles, the field of environmentally friendly biodegradable textiles with microcapsules is still at an early stage of development. So far, some physicochemical and physical microencapsulation methods using natural polymers or biodegradable synthetic polymers have been applied to produce environmentally friendly antimicrobial, anti-inflammatory or fragranced textiles. Standardised test methods for evaluating the biodegradability of textile materials are available. The stability of biodegradable microcapsules and the durability of coatings during the use and care of textiles still present several challenges that offer many opportunities for further research.

Microemulsification of essential oils for the development of antimicrobial and mosquito repellent functional coatings for textiles

AIMS

To develop an essential oil (EO)-loaded textile coating using an environmentally friendly microemulsion technique to achieve both antimicrobial and mosquito repellent functionalities.

METHODS AND RESULTS

Minimum inhibitory concentrations and fractional inhibitory concentrations of litsea, lemon and rosemary EOs were determined against Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa and Trichophyton rubrum. A 1 : 2 mixture of litsea and lemon EOs inhibited all the microorganisms tested and was incorporated into a chitosan-sodium alginate assembly by a microemulsification process. The EO-loaded microemulsions were applied to cotton and polyester fabrics using a soak-pad-dry method. The textile challenge tests demonstrated 7-8 log₁₀ reductions of S. epidermidis, S. aureus and E. coli after 24 h and T. rubrum after 48 h. Aedes aegypti mosquito repellency was also assessed which demonstrated 71·43% repellency compared to 52·94% by neat EO-impregnated cotton.

CONCLUSIONS

Textiles treated with the litsea and lemon EO microemulsion showed strong antimicrobial activity against the skin associated microorganisms E. coli, S. aureus, S. epidermidis and T. rubrum and potential mosquito repellent properties.

SIGNIFICANCE AND IMPACT OF THE STUDY

EOs could be useful for the development of natural, environmentally friendly functional textiles to protect textiles and users from microbial contamination in addition to possessing other beneficial properties such as mosquito repellency.