Fabrication, Optimization, and Characterization of Antibacterial Electrospun Shellac Fibers Loaded with Kaempferia parviflora Extract

Shellac-based materials: Structures, properties, and applications

Shellac stands out among natural polymers as the sole animal-derived resin, boasting a complex polyester composition comprising polyhydroxy long-chain fatty acids and sesquiterpene acids. Its unique attributes include biocompatibility, non-toxicity, distinctive amphiphilicity, superb film-forming and adhesive properties, excellent dielectric properties, rapid drying, and solubility in alkaline solutions while resisting acidic ones. These exceptional qualities have propelled shellac beyond its traditional role as a varnish and decorative material, positioning it as a viable option for diverse applications such as food packaging, pharmaceutical formulations, electronic devices, fiber dyeing, and wood restoration. Furthermore, shellac serves as a crucial carbon source for graphene materials. This review comprehensively explores shellac's contributions to prolonging food shelf life, enhancing the carbon sourcing of graphene materials, facilitating the delivery of active substances, boosting the performance of organic field-effect transistors, enabling environmentally friendly textile dyeing, and providing protective coatings for wood. Additionally, it delves into the current limitations and future directions of shellac's applications. By disseminating this knowledge, we aim to deepen researchers' comprehension of shellac and inspire further exploration, thereby fostering sustainable advancements across various industries.

Fabrication and evaluation of ribavirin-loaded electrospun nanofibers as an antimicrobial wound dressing

Background

Skin is regarded as an essential first line of defense against harmful pathogens and it hosts an ecosystem of microorganisms that create a widely diverse skin microbiome. In chronic wounds, alterations in the host-microbe interactions occur forming polymicrobial biofilms that hinder the process of wound healing. Ribavirin, an antiviral drug, possesses antimicrobial activity, especially against Pseudomonas aeruginosa and Candida albicans, which are known as the main opportunistic pathogens in chronic wounds.

Rationale

In this study, electrospun nanofiber systems loaded with ribavirin were developed as a potential wound dressing for topical application in chronic wounds. Ribavirin was chosen in this study owing to the emerging cases of antimicrobial (antibiotics and antifungal) resistance and the low attempts to discover new antimicrobial agents, which encouraged the repurposing use of current medication as an alternative solution in case of resistance to the available agents. Additionally, the unique mechanism of action of ribavirin, i.e., perturbing the bacterial virulence system without killing or stopping their growth and rendering the pathogens disarmed, might be a promising choice to prevent drug resistance. Cyclodextrin (CD) was utilized to formulate ribavirin as an electrospun nanofibers delivery system to enhance the absorption and accelerate the release of ribavirin for topical use.

Results

The results demonstrated a successful ribavirin nanofibers fabrication that lacked beads and pores on the nanofibrous surfaces. Ribavirin underwent a physical transformation from crystalline to amorphous form, as confirmed by X-ray diffraction analysis. This change occurred due to the molecular dispersion after the electrospinning process. Additionally, the CD enhanced the encapsulation efficiency of ribavirin in the nanofibers as observed from the drug-loading results. Polyvinylpyrrolidone (PVP) and CD increased ribavirin released into the solution and the disintegration of fibrous mats which shrank and eventually dissolved into a gel-like substance as the ribavirin-loaded fibers began to break down from their border toward the midpoint. Cytotoxicity of ribavirin and CD was evaluated against human dermal fibroblasts (HFF-1) and the results showed a relatively safe profile of ribavirin upon 24-hour cell exposure, while CD was safe within 24- and 48-hour.

Conclusion

This study provides valuable insights into the potential application of our nanofibrous system for treating chronic wounds; however, further antimicrobial and in-vivo studies are required to confirm its safety and effectiveness.

Fabrication and Optimization of Electrospun Shellac Fibers Loaded with Senna alata Leaf Extract

Single-fluid electrospinning creates nanofibers from molten polymer solutions with active ingredients. This study utilized a combination of a fractional factorial design and a Box-Behnken design to examine crucial factors among a multitude of parameters and to optimize the electrospinning conditions that impact fiber mats' morphology and the entrapment efficiency of Senna alata leaf extract. The findings indicated that the shellac content had the greatest impact on both fiber diameter and bead formation. The optimum electrospinning conditions were identified as a voltage of 24 kV, a solution feed rate of 0.8 mL/h, and a shellac-extract ratio of 38.5:3.8. These conditions produced nanosized fibers with a diameter of 306 nm, a low bead-to-fiber ratio of 0.29, and an extract entrapment efficiency of 96% within the fibers. The biphasic profile of the optimized nanofibers was confirmed with an in vitro release study. This profile consisted of an initial burst release of 88% within the first hour, which was succeeded by a sustained release pattern surpassing 90% for the next 12 h, as predicted with zero-order release kinetics. The optimized nanofibers demonstrated antimicrobial efficacy against diverse pathogens, suggesting promising applications in wound dressings and protective textiles.

Advances in Natural Product Extraction Techniques, Electrospun Fiber Fabrication, and the Integration of Experimental Design: A Comprehensive Review

The present review explores the growing interest in the techniques employed for extracting natural products. It emphasizes the limitations of conventional extraction methods and introduces superior non-conventional alternatives, particularly ultrasound-assisted extraction. Characterization and quantification of bioactive constituents through chromatography coupled with spectroscopy are recommended, while the importance of method development and validation for biomarker quantification is underscored. At present, electrospun fibers provide a versatile platform for incorporating bioactive extracts and have extensive potential in diverse fields due to their unique structural and functional characteristics. Thus, the review also highlights the fabrication of electrospun fibers containing bioactive extracts. The preparation of biologically active extracts under optimal conditions, including the selection of safe solvents and cost-effective equipment, holds promising potential in the pharmaceutical, food, and cosmetic industries. Integration of experimental design into extraction procedures and formulation development is essential for the efficient production of health products. The review explores potential applications of encapsulating natural product extracts in electrospun fibers, such as wound healing, antibacterial activity, and antioxidant properties, while acknowledging the need for further exploration and optimization in this field. The findings discussed in this review are anticipated to serve as a valuable resource for the processing industry, enabling the utilization of affordable and environmentally friendly, natural, and raw materials.

A Brief Review on the Electrohydrodynamic Techniques Used to Build Antioxidant Delivery Systems from Natural Sources

Extracts from plants have been one of the main sources of antioxidants, namely polyphenols. The associated drawbacks, such as instability against environmental factors, low bioavailability, and loss of activity, must be considered during microencapsulation for a better application. Electrohydrodynamic processes have been investigated as promising tools to fabricate crucial vectors to minimize these limitations. The developed microstructures present high potential to encapsulate active compounds and for controlling their release. The fabricated electrospun/electrosprayed structures present different benefits when compared with structures developed by other techniques; they present a high surface-area-to-volume ratio as well as porosity, great materials handling, and scalable production-among other advantages-which make them able to be widely applied in different fields, namely in the food industry. This review presents a summary of the electrohydrodynamic processes, main studies, and their application.