Preparation of oil-in-water core-sheath nanofibers through emulsion electrospinning for phase change temperature regulation

Electrospinning: A New Frontier in Peptide Therapeutics

The nanofiber technology has recently undergone an unprecedented transformation, finding widespread utilities across diverse scientific disciplines. It is noteworthy that electrospinning approaches have emerged as an adaptable and successful approach to generate fibers ranging in rapidly as a class of therapeutic agents with a high level of target specificity. Peptides encounter several challenges as drugs, including swift breakdown by the body, rapid elimination from the bloodstream, inadequate stability, and restricted ability to cross cell membranes. This renders it challenging to employ them as drugs. However, electrospun nanofibers might address these problems. This review explores the promising potential of electrospinning nanofibers for peptide delivery. We delve into recent advancements in this technique, highlighting its effectiveness in overcoming challenges associated with peptide drug delivery. It provides an analysis of the trends identified in the use of the electrospinning technique and its role in peptide drug delivery systems, based on a review of data collected over a period of five to seven years.

Preparation of starch-based oral fast-disintegrating nanofiber mats for astaxanthin encapsulation and delivery via emulsion electrospinning

Developing green and efficient delivery systems to promote bioavailability of bioactive ingredients is a sustained demand in food industry. In this work, the astaxanthin (AST)-loaded starch-based fast-dissolving nanofibers with core-shell structure were prepared by emulsion electrospinning technique without using any organic solvent. To load water-insoluble AST in hydrophilic octenyl succinic anhydride starch (OSAS)/polyvinyl alcohol (PVA) nanofiber matrices, AST-loaded nanoscale emulsions (212.19 ± 5.63 nm) with high encapsulation efficiency (91.54 ± 0.14 %) were prepared as a precursor for emulsion electrospinning, using OSAS/PVA aggregates as an emulsifier. The core-shell structure of nanofibers was revealed by the Transmission electron microscopy (TEM), with average diameter of 509.58 ± 12.77 nm, and 88.64 ± 0.49 % for AST were effectively encapsulated in core layer. Nanofiber mats exhibited high encapsulation efficiency (85.11 ± 1.53 %) and excellent storage stability over 7 d. Meanwhile, amorphous transformation of AST enabled it possess higher water solubility, bioaccessibility, and antioxidant properties (97.72 ± 2.17 %) than free AST in aqueous system. The results demonstrated that the green, nontoxic, and biodegradable nanofiber mats prepared by emulsion electrospinning successfully realized the encapsulation and delivery of AST, with broad application prospects in the food and pharmaceutical fields.

Fabrication and characterization of oleic acid/sesame protein isolate/ poly (vinyl) alcohol core-shell nanofibers: Mitigating lipid oxidation by emulsion electrospinning

Formulated oil-in-water (O/W) emulsions of oleic acid (OA) using sesame protein isolate (SPI) were processed via emulsion electrospinning with poly (vinyl) alcohol (PVA) to fabricate core-shell nanofibers for lipid oxidation prevention. The emulsion droplet size and viscosity increased as the oil volume fraction rose from 5 % to 30 %. The morphology tests and Fourier transform infrared spectroscopy (FTIR) confirmed the uniformity of nanofibers and OA encapsulation with hydrogen bonding. The thermal stability, mechanical properties, and water contact angle (WCA) of the nanofiber films improved with increased OA content. Encapsulation efficiency was 94.76 % and storage stability was maintained for 7 days in 5 % oil fraction nanofibers. The nanofibers showed lower oxidation and superior oxidative resistance to free OA, with the lowest peroxide value (POV, 2.14 mmol/L) and thiobarbituric acid-reactive substances (TBARS, 36.75 μmol/L). In conclusion, the OA/SPI/PVA (PE) core-shell nanofibers via emulsion electrospinning are efficient for fatty acid encapsulation in functional foods.

Phase-Changeable Metafabric Enables Dynamic Subambient Humidity and Thermal Regulation

A promising approach to prevent heat- and cold-related illnesses is the integration of zero-energy input control technology into personal thermal management (PTM) systems while reducing energy consumption. However, achieving optimal wearing comfort while maintaining subambient metabolic temperatures using thermally regulating materials without an energy supply remains challenging. In this study, we provide a simple and reliable methodology to produce a phase-changeable metafabric made of thermoplastic polyurethane and phase change capsule (PCC) particles with high moisture permeability and thermal comfort. This approach skillfully incorporates spray-formed PCC particles into a three-dimensional nanofibrous aggregate, forming a stable self-entangled network structure in a single step through simultaneous humidity-assisted electrospraying and electrospinning processes. Additionally, the metafabric demonstrates prominent water resistance and superhydrophobicity, which are attributed to the integration of PCC particles and nanofibers, resulting in the formation of a microporous/nanoporous structure resembling the surface of a lotus leaf. As a result, the phase-changeable metafabric shows an active and passive thermal control performance, with a water vapor transmittance rate of 13.1 kg m-2 d-1 and a phase change enthalpy of 115.05 J g-1 even after 100 thermal cycles. Furthermore, it displays excellent waterproofing capability, characterized by a water contact angle of 158.7° and the ability to withstand a high hydrostatic pressure of 87 kPa. In addition, the metafabric exhibits a good mechanical performance, boasting a tensile strength of 10.5 MPa. Overall, the proposed economical metafabric is an exemplary candidate material for next-generation PTM systems.

Fabrication and characterization of electrospun core-shell nanofibers of bilayer zein/pullulan emulsions crosslinked by genipin

In this study, the electrospun core-shell nanofibers of zein/pullulan stabilized bilayer emulsions before and after genipin crosslinking were fabricated. The experimental results indicated that the addition of pullulan increased the apparent viscosity and elastic modulus of the bilayer emulsions, which was further increased after the chemical crosslinking of genipin. The nanofiber diameter increased from 102.9 nm to 169.9 nm with the increasing ratio of pullulan, but increased significantly to a range of 405.6-708.0 nm after genipin crosslinking. The electrospun nanofiber films of crosslinked emulsions had higher thermal stability and stronger water stability. The FTIR result proved the existence of hydrogen bond interaction between the zein, pullulan, and genipin molecules. In addition, before and after crosslinking, the encapsulation efficiency of electrospun fiber films for camellia oil was >77.68 %, and the maximum encapsulation efficiency could reach 87.94 %, and there was no significant change during the 7-day storage period, showing good stability. These research results can provide a theoretical basis for the encapsulation of hydrophobic active substances in zein-based emulsion electrospun core-shell nanofibers.

Hydrophobic Multilayered PEG@PAN/MXene/PVDF@SiO2 Composite Film with Excellent Thermal Management and Electromagnetic Interference Shielding for Electronic Devices

With the rapid development of electronic industry, it's pressing to develop multifunctional electromagnetic interference (EMI) shielding materials to ensure the stable operation of electronic devices. Herein, multilayered flexible PEG@PAN/MXene (Ti3C2Tx)/PVDF@SiO2 (PMF) composite film has been constructed from the level of microstructure design via coaxial electrospinning, coating spraying, and uniaxial electrospinning strategies. Benefiting from the effective encapsulation for PEG and high conductivity of MXene coating, PEG@PAN/MXene composite film with MXene coating loading density of 0.70 mg cm-2 exhibits high thermal energy storage density of 120.77 J g-1 and great EMI shielding performance (EMI SE of 34.409 dB and SSE of 49.086 dB cm3 g-1) in X-band (8-12 GHz). Therefore, this advanced composite film can not only help electronic devices prevent the influence of electromagnetic pollution in the X-band but also play an important role in electronic device thermal management. Additionally, the deposition of nano PVDF@SiO2 fibers (289 ± 128 nm) endowed the PMF composite film with great hydrophobic properties (water contact angle of 126.5°) to ensure the stable working of hydrophilic MXene coating, thereby breaks the limitation of humid application environments. The finding paves a new way for the development of novel multifunctional EMI shielding composite films for electronic devices.

Flexible Highly Thermally Conductive PCM Film Prepared by Centrifugal Electrospinning for Wearable Thermal Management

Personal thermal management materials integrated with phase-change materials have significant potential to satisfy human thermal comfort needs and save energy through the efficient storage and utilization of thermal energy. However, conventional organic phase-change materials in a solid state suffer from rigidity, low thermal conductivity, and leakage, making their application challenging. In this work, polyethylene glycol (PEG) was chosen as the phase-change material to provide the energy storage density, polyethylene oxide (PEO) was chosen to provide the backbone structure of the three-dimensional polymer network and cross-linked with the PEG to provide flexibility, and carbon nanotubes (CNTs) were used to improve the mechanical and thermal conductivity of the material. The thermal conductivity of the composite fiber membranes was boosted by 77.1% when CNTs were added at 4 wt%. Water-resistant modification of the composite fiber membranes was successfully performed using glutaraldehyde-saturated steam. The resulting composite fiber membranes had a reasonable range of phase transition temperatures, and the CC4PCF-55 membranes had melting and freezing latent heats of 66.71 J/g and 64.74 J/g, respectively. The results of this study prove that the green CC4PCF-55 composite fiber membranes have excellent flexibility, with good thermal energy storage capacity and thermal conductivity and, therefore, high potential in the field of flexible wearable thermal management textiles.

Use of Electrospinning for Sustainable Production of Nanofibers: A Comparative Assessment of Smart Textiles-Related Applications

Textile production is a major component of the global industry, with sales of over USD 450 billion and estimations of an 84% increase in their demand in the next 20 years. In recent decades, protective and smart textiles have played important roles in the social economy and attracted widespread popularity thanks to their wide spectrum of applications with properties, such as antimicrobial, water-repellent, UV, chemical, and thermal protection. Towards the sustainable manufacturing of smart textiles, biodegradable, recycled, and bio-based plastics are used as alternative raw materials for fabric and yarn production using a wide variety of techniques. While conventional techniques present several drawbacks, nanofibers produced through electrospinning have superior structural properties. Electrospinning is an innovative method for fiber production based on the use of electrostatic force to create charged threads of polymer solutions. Electrospinning shows great potential since it provides control of the size, porosity, and mechanical resistance of the fibers. This review summarizes the advances in the rapidly evolving field of the production of nanofibers for application in smart and protective textiles using electrospinning and environmentally friendly polymers as raw materials, and provides research directions for optimized smart fibers in the future.

Edible polysaccharide-based oleogels and novel emulsion gels as fat analogues: A review

Polysaccharide-based oleogels and emulsion gels have become novel strategies to replace solid fats due to safe and plentiful raw material, healthier fatty acid composition, controllable viscoelasticity, and more varied nutrition/flavor embedding. Recently, various oleogelation techniques and novel emulsion gels have been reported further to enrich the potential of polysaccharides in oil structuring, in which a crucial step is to promote the formation of polysaccharide networks determining gel properties through different media. Meanwhile, polysaccharide-based oleogels and emulsion gels have good oil holding, nutrient/flavor embedding, and 3D food printability, and their applications as fat substitutes have been explored in foods. This paper comprehensively reviews the types, preparation methods, and mechanisms of various polysaccharide-based oleogels and emulsion gels; meanwhile, the food applications and new trends of polysaccharide-based gels are discussed. Moreover, some viewpoints about potential developments and application challenges of polysaccharide-based gels are mentioned. In the future, polysaccharide-based gels may be flexible materials for customized nutritional foods and molecular gastronomy. However, it is still a challenge to select the appropriate oleogels or emulsion gels to meet the requirements of the products. Once this issue is addressed, oleogels and emulsion gels are anticipated to be used widely.

Stable encapsulation of camellia oil in core-shell zein nanofibers fabricated by emulsion electrospinning

This study aimed to develop core-shell nanofibers by emulsion electrospinning using zein-stabilized emulsions to encapsulate camellia oil effectively. The increasing oil volume fraction (φ from 10% to 60%) increased the apparent viscosity and average droplet size of emulsions, resulting in the average diameter of electrospun fibers increasing from 124.5 nm to 286.2 nm. The oil droplets as the core were randomly distributed in fibers in the form of beads, and the core-shell structure of fibers was observed in TEM images. FTIR indicated that hydrogen bond interactions occurred between zein and camellia oil molecules. The increasing oil volume fraction enhanced the thermal stability, hydrophobicity, and water stability of electrospun nanofiber films. The core-shell nanofibers with 10%, 20%, 40%, and 60% camellia oil showed encapsulation efficiency of 78.53%, 80.25%, 84.52%, and 84.39%, respectively, and had good storage stability. These findings contribute to developing zein-based core-shell electrospun fibers to encapsulate bioactive substances.

Robust microfluidic construction of polyvinyl pyrrolidone microfibers incorporated with W/O emulsions stabilized by amphiphilic konjac glucomannan

In this work, we prepared polyvinyl pyrrolidone (PVP) microfibers incorporated water-in-oil (W/O) emulsions. The W/O emulsions were fabricated by hexadecyl konjac glucomannan (HKGM, emulsifier), corn oil (oil phase) and purple corn anthocyanins (PCAs, water phase). The structures and functions of emulsions and microfibers were characterized by confocal laser scanning (CLSM) and scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and nuclear magnetic resonance (NMR) spectroscopy. The results showed that W/O emulsions exhibited good storage stability for 30 d. Microfibers presented ordered and uniform arrays. Compared with pure PVP microfiber films, the addition of W/O emulsions with PCAs improved the water resistance (WVP from 1.28 to 0.76 g mm/m² day kPa), mechanical strength (Elongation at break from 18.35 % to 49.83 %), antioxidation (free radical scavenging rate from 2.58 % to 16.37 %), and antibacterial activity (inhibition zone against E. coli: 27.33 mm and inhibition zone against S. aureus: 28.33 mm) of microfiber films. Results showed that microfiber film exhibited controlled release of PCAs in W/O emulsions, and about 32 % of the PCAs were released from the microfiber film after 340 min. The as-prepared microfiber films exhibited potential applications for food packaging.

Biofunctionalization and Applications of Polymeric Nanofibers in Tissue Engineering and Regenerative Medicine

The limited ability of most human tissues to regenerate has necessitated the interventions namely autograft and allograft, both of which carry the limitations of its own. An alternative to such interventions could be the capability to regenerate the tissue in vivo.Regeneration of tissue using the innate capacity of the cells to regenerate is studied under the discipline of tissue engineering and regenerative medicine (TERM). Besides the cells and growth-controlling bioactives, scaffolds play the central role in TERM which is analogous to the role performed by extracellular matrix (ECM) in the vivo. Mimicking the structure of ECM at the nanoscale is one of the critical attributes demonstrated by nanofibers. This unique feature and its customizable structure to befit different types of tissues make nanofibers a competent candidate for tissue engineering. This review discusses broad range of natural and synthetic biodegradable polymers employed to construct nanofibers as well as biofunctionalization of polymers to improve cellular interaction and tissue integration. Amongst the diverse ways to fabricate nanofibers, electrospinning has been discussed in detail along with advances in this technique. Review also presents a discourse on application of nanofibers for a range of tissues, namely neural, vascular, cartilage, bone, dermal and cardiac.

Modification and Functionalization of Fibers Formed by Electrospinning: A Review

The development of new materials with specific functionalities for certain applications has been increasing with the advent of nanotechnology. A technique widely used for this purpose is electrospinning, because control of several parameters involved in the process can yield nanoscale fibers. In addition to the production of innovative and small-scale materials, through structural, chemical, physical, and biological modifications in the fibers produced in electrospinning, it is possible to obtain specific properties for a given application. Thus, the produced fibers can serve different purposes, such as in the areas of sensors, catalysis, and environmental and medical fields. Given this context, this article presents a review of the electrospinning technique, addressing the parameters that influence the properties of the fibers formed and some techniques used to modify them as specific treatments that can be conducted during or after electrospinning. In situ addition of nanoparticles, changes in the configuration of the metallic collector, use of alternating current, electret fibers, core/shell method, coating, electrospray-coating, plasma, reinforcing composite materials, and thermal treatments are some of the examples addressed in this work. Therefore, this work contributes to a better comprehension of some of the techniques mentioned in the literature so far.