Ultrafine noble metals have emerged as advanced nanocatalysts in modern society but still suffer from unavoidable sintering at temperatures above 250 °C (e.g., Pt). In this work, closely packed CeO2 grains were confined elegantly in fibrous nanostructures and served as a porous support for stabilizing sub-3 nm Pt clusters. Through precisely manipulating the asymmetry of obtained nanofibers, uneven strain was induced within C-shaped CeO2 nanofibers with tensile strain at the outer side and compressive strain at the inner side. As a result, the enriched oxygen vacancies significantly improved adhesion of Pt to CeO2, thereby boosting the sinter-resistance of ultraclose sub-3 nm Pt clusters. Notably, no aggregation was observed even after exposure to humid air at 750 °C for 12 h, which is far beyond their Tammann temperature (sintering onset temperature, below 250 °C). In situ HAADF-STEM observation revealed a unique sintering mechanism, wherein Pt clusters initially migrate toward the grain boundaries with concentrated stain and undergo slight coalescence, followed by subsequent Ostwald ripening at higher temperatures. Moreover, the sinter-resistant Pt/C-shaped CeO2 effectively catalyzed soot combustion (over 700 °C) in a durable manner. This work provides a new insight for developing sinter-resistant catalysts from the perspective of strain engineering within nano-oxides.

Oral leukoplakia (OLK) is the most common oral precancerous lesion, and 3%-17% of OLK patients progress to oral squamous cell carcinoma. OLK is susceptible to recurrence and has no effective treatment. However, conventional drugs have significant side effects and limitations. Therefore, it is important to identify drugs that target OLK. In this study, scavenger receptor A (SR-A) was found to be abnormally highly expressed in the oral mucosal epithelial cells of OLK patients, whereas molecular biology studies revealed that low molecular weight fucoidan (LMWF) promoted apoptosis of dysplastic oral keratinocytes (DOK) and inhibited the growth and migration of DOK, and the inhibitory effect of LMWF on OLK was achieved by regulating the SR-A/Wnt signaling axis and related genes. Based on the above results and the special situation of the oral environment, we constructed LMWF/poly(caprolactone-co-lactide) nanofiber membranes with different structures for the in-situ treatment of OLK using electrospinning technology. The results showed that the nanofiber membranes with a shell-core structure had the best physicochemical properties, biocompatibility, and therapeutic effect, which optimized the LMWF drug delivery and ensured the effective concentration of the drug at the target point, thus achieving precise treatment of local lesions in the oral cavity. This has potential application value in inhibiting the development of OLK.

Triboelectric nanogenerators (TENGs) have become reliable green energy harvesters by converting biomechanical motions into electricity. However, the inevitable charge leakage and poor electric field (EF) of conventional TENG result in inferior tribo-charge density on the active layer. In this paper, TiO2-MXene incorporated polystyrene (PS) nanofiber membrane (PTMx NFM) charge trapping interlayer is introduced into single electrode mode TENG (S-TENG) to prevent electron loss at the electrode interface. Surprisingly, this charge-trapping mechanism augments the surface charge density and electric output performance of TENGs. Polyvinylidene difluoride (PVDF) mixed polyurethane (PU) NFM is used as tribo-active layer, which improves the crystallinity and mechanical property of PVDF to prevent delamination during long cycle tests. Herein, the effect of this double-layer capacitive model is explained experimentally and theoretically. With optimization of the PTMx interlayer thickness, S-TENG exhibits a maximum open-circuit voltage of (280 V), short-circuit current of (20 µA) transfer charge of (120 nC), and power density of (25.2 µW cm-2). Then, this energy is utilized to charge electrical appliances. In addition, the influence of AC/DC EF simulation in wound healing management (vitro L929 cell migration, vivo tissue regeneration) is also investigated by changing the polarity of trans-epithelial potential (TEP) distribution in the wounded area.

Traumatic brain injury poses serious physical, psychosocial, and economic threats. Although systemic administration of stem cell-derived exosomes has recently been proven to be a promising modality for traumatic brain injury treatment, they come with distinct drawbacks. Luckily, various biomaterials have been developed to assist local delivery of exosomes to improve the targeting of organs, minimize nonspecific accumulation in vital organs, and ensure the protection and release of exosomes. In this study, we developed an electrospun nanofibrous scaffold to provide sustained delivery of dual exosomes derived from mesenchymal stem cells and neural stem cells for traumatic brain injury treatment. The electrospun nanofibrous scaffold employed a functionalized layer of polydopamine on electrospun poly(ε-caprolactone) nanofibers, thereby enhancing the efficient incorporation of exosomes through a synergistic interplay of adhesive forces, hydrogen bonding, and electrostatic interactions. First, the mesenchymal stem cell-derived exosomes and the neural stem cell-derived exosomes were found to modulate microglial polarization toward M2 phenotype, play an important role in the modulation of inflammatory responses, and augment axonal outgrowth and neural repair in PC12 cells. Second, the nanofibrous scaffold loaded with dual stem cell-derived exosomes (Duo-Exo@NF) accelerated functional recovery in a murine traumatic brain injury model, as it mitigated the presence of reactive astrocytes and microglia while elevating the levels of growth associated protein-43 and doublecortin. Additionally, multiomics analysis provided mechanistic insights into how dual stem cell-derived exosomes exerted its therapeutic effects. These findings collectively suggest that our novel Duo-Exo@NF system could function as an effective treatment modality for traumatic brain injury using sustained local delivery of dual exosomes from stem cells.

Nerve guidance conduits (NGCs) are considered as promising treatment strategy and frontier trend for peripheral nerve regeneration, while their therapeutic outcomes are limited by the lack of controllable drug delivery and available physicochemical cues. Herein, novel aligned piezoelectric nanofibers derived hydrogel NGCs with ultrasound (US)-triggered electrical stimulation (ES) and controllable drug release for repairing peripheral nerve injury are proposed. The inner layer of the NGCs is the barium titanate piezoelectric nanoparticles (BTNPs)-doped polyvinylidene fluoride-trifluoroethylene [BTNPs/P(VDF-TrFE)] electrospinning nanofibers with improved piezoelectricity and aligned orientation. The outer side of the NGCs is the thermoresponsive poly(N-isopropylacrylamide) hybrid hydrogel with bioactive drug encapsulation. Such NGCs can not only induce neuronal-oriented extension and promote neurite outgrowth with US-triggered wireless ES, but also realize the controllable nerve growth factor release with the hydrogel shrinkage under US-triggered heating. Thus, the NGC can positively accelerate the functional recovery and nerve axonal regeneration of rat models with long sciatic nerve defects. It is believed that the proposed US-responsive aligned piezoelectric nanofibers derived hydrogel NGCs will find important applications in clinic neural tissue engineering.

Electrospinning is a promising technique for the beneficial use and recycling of plastic waste polymers using simple methodologies. In this study, plastic bottles and Styrofoam wastes have been used to develop polyethylene terephthalate (PET) and polystyrene (PS) nanofibers using electrospinning technique separately without any further purification. The effect of the concentration onto the nanofiber\'s morphology was studied. The fabricated nanofibers were characterized using Field Emission Scanning Electron Microscope (FE-SEM), Fourier Transformed Infrared Spectroscopy (ATR-FTIR), N2 adsorption/desorption analysis, and water contact angle (WCA). Furthermore, the prepared nanofibers were applied for the adsorption of ibuprofen (IBU) from wastewater. Some parameters that can influence the adsorption efficiency of nanofibers such as solution pH, wt.% of prepared nanofibers, drug initial concentration, and contact time were studied and optimized. The results show that the equilibrium adsorption capacity was achieved after only 10 min for 12 wt% PET nanofibers which is equivalent to 364.83 mg/g. For 12 wt% PS nanofibers, an equilibrium adsorption capacity of 328.42 mg/g was achieved in 30 min. The experimental data was fitted to five isotherm and four kinetics models to understand the complicated interaction between the nanofibers and the drug. Langmuir-Freundlich isotherm model showed the best fit for experimental data for both PET and PS nanofibers. The adsorption process was characterized by predominantly physical reaction rather than chemical adsorption for both materials. The reusability study revealed that the synthesized nanofibers maintain their ability to adsorb/desorb IBU for up to five cycles. The results obtained demonstrated that fabricated nanofibers from plastic wastes could perform promising adsorbents for the management of IBU in wastewater. However, further research is needed for the scaling-up the fabrication which is required for real-world applications.

Water evaporation-driven energy harvesting is an emerging mechanism for contributing to green energy production with low cost. Herein, we developed polyacrylonitrile (PAN) nanofiber-based evaporation-driven electricity generators (PEEGs) to confirm the feasibility of utilizing electrospun PAN nanofiber mats in an evaporation-driven energy harvesting system. However, PAN nanofiber mats require a support substrate to enhance its durability and stability when it is applied to an evaporation-driven energy generator, which could have additional effects on generation performance. Accordingly, various support substrates, including fiberglass, copper, stainless mesh, and fabric screen, were applied to PEEGs and examined to understand their potential impacts on electrical generation outputs. As a result, the PAN nanofiber mats were successfully converted to a hydrophilic material for an evaporation-driven generator by dip-coating them in nanocarbon black (NCB) solution. Furthermore, specific electrokinetic performance trends were investigated and the peak electricity outputs of Voc were recorded to be 150.8, 6.5, 2.4, and 215.9 mV, and Isc outputs were recorded to be 143.8, 60.5, 103.8, and 121.4 μA, from PEEGs with fiberglass, copper, stainless mesh, and fabric screen substrates, respectively. Therefore, the implications of this study would provide further perspectives on the developing evaporation-induced electricity devices based on nanofiber materials.

Electrospun polymeric nanofibrous membranes are emerging as the promising substrates for preparation of flexible SERS nanosensors due to their intrinsic nanoscale surface roughness, easy scalability as well as rich surface reactivity. Although the nanofiber membranes prepared from high performance thermoplastics exhibit good mechanical stability, the SERS nanosensors based on these substrates normally have lower signal-to-noise ratio because of the interference from background Raman signals of aromatic moieties. Herein, we synthesized an optically transparent polyurethane (PU) and rigid polyarylene ether amidoxime (PEA), which were electrospun into core-shell nanofibers membranes with a \"beads-on-web\" morphology. Furthermore, the PU-PEA membranes were coated with ultra-thin silver layer and thermally annealed to prepare the flexible SERS nanosensor without any background noises. In addition, the Raman enhancement of SERS nanosensor can be readily improved by tuning of PU-PEA composition, silver thickness as well as thermal annealing temperature. Finally, the optimized SERS nanosensor enables label-free detection of sulfamethoxazole as low as 0.1 nM with a good reproducibility and detection performance in real water sample. Meanwhile, the optimized SERS nanosensor shows long term anti-biofouling capacity. Thanks to its facile fabrication, competitive analytical performance and resistance to biofouling, the current work basically open new way for design of flexible SERS nanosensors for biomedical applications.

Stretchable electronics have experienced remarkable progress, especially in sensors and wireless communication systems, attributed to their ability to conformably contact with rough or uneven surfaces. However, the development of complex, multifunctional, and high-precision stretchable electronics faces substantial challenges, including instability at rigid-soft interfaces and incompatibility with traditional high-precision patterning technologies. Metallized electrospun nanofibers emerge as a promising conductive filler, offering exceptional stretchability, electrical conductivity, transparency, and compatibility with existing patterning technologies. Here, this review focuses on the fundamental properties, preparation processes, patterning technologies, and application scenarios of conductive stretchable composites based on metallized nanofibers. Initially, it introduces the fabrication processes of metallized electrospun nanofibers and their advantages over alternative materials. It then highlights recent progress in patterning technologies, including collector collection, vapor deposition with masks, and lithography, emphasizing their role in enhancing precision and integration. Furthermore, the review shows the broad applicability and potential influence of metallized electrospun nanofibers in various fields through their use in sensors, wireless systems, semiconductor devices, and intelligent healthcare solutions. Ultimately, this review seeks to spark further innovation and address the prevailing challenges in stretchable electronics, paving the way for future breakthroughs in this dynamic field.

Biopolymer-based electrospun mats, mimicking the extracellular matrix, have been extensively explored in biomedical applications. This study compares Achillea millefolium (AM) and Viola (V) extracts for developing a biocompatible wound dressing. The extracts were incorporated into a Chitosan/polyvinyl alcohol (CS/PVA) matrix via electrospinning. Crosslinking with Carbonyldiimidazole (CDI) improved chemical stability, water resistance, and biodegradability. The resulting mats exhibited flawless interconnected nanofibers, confirming the presence of AM and Viola extracts as analyzed via FTIR. Significant differences were observed between these two herbal extracts, particularly in mechanical properties, with tensile strengths of 6.9 MPa for AM and 17.2 MPa for Viola. Viola extract demonstrated robust antibacterial properties, producing an 8.2 mm inhibition zone against Staphylococcus aureus, compared to AM\'s 30 %. The release of therapeutic agents indicated an initial rapid phase, followed by a controlled 72 h release at a consistent rate. Notably, Viola extract led to 80.9 % wound closure on the 10th day, surpassing AM extract at 63.7 %. In contrast, the control group achieved only 32.1 % closure. This comparative study underscores the distinct advantages of AM and Viola extracts in wound dressing applications. While AM presents specific strengths, Viola extract exhibits superior mechanical properties, antibacterial efficacy, and accelerated wound closure, suggesting its potential with significant clinical implications.