Diabetic foot ulcer (DFU) often evolves into chronic wounds that resist healing over an extended period, sometimes necessitating amputation in severe cases. Traditional wound management approaches generally fail to control these chronic sores successfully. Thus, it arouses a huge demand in clinic for a novel wound dressing to treat DFU effectively. Hydrogel as an ideal delivery system exhibits excellent loading capacity and sustainable release behavior. It also boasts tunable physical and chemical properties adaptable to diverse biomedical scenarios, making it a suitable material for fabricating functional wound dressings to treat DFU. The hydrogel dressings are classified into hemostatic, antibacterial and anti-inflammatory, and healing-promoting hydrogel dressings by associating the pathogenesis of DFU in this paper. The design and fabrication strategies for the dressings, as well as their therapeutic effects in treating DFU, are extensively reviewed. Additionally, this paper highlights future perspectives of multifunctional hydrogel dressings in DFU treatment. This review aims to provide valuable references for material scientists to design and develop hydrogel wound dressings with enhanced capabilities for DFU treatment, and to further translate them into the clinic in the future.
Flexible sensors with high sensitivity and stability are essential components of electronic skin, applicable to detecting human movement, monitoring physiological health, preventing diseases, and other domains. In this study, we utilized a straightforward and efficient femtosecond laser direct writing technique using phenolic resin (PR) as a carbon precursor to produce high-quality laser-induced graphene (LIG) characterized by high crystallinity and low defect density. The fabricated LIG underwent comprehensive characterization using SEM, Raman spectroscopy, XPS, and XRD. Subsequently, we developed strain sensors with a hexagonal honeycomb pattern and temperature sensors with a line pattern based on PR-derived LIG. The strain sensor exhibited an outstanding measurement factor of 4.16 × 104 with a rapid response time of 32 ms, which is applied to detect various movements like finger movements and human pulse. Meanwhile, the temperature sensor demonstrated a sensitivity of 1.49%/°C with a linear response range of 20–50 °C. The PR-derived LIG shows promising potential for applications in human physiological health monitoring and other advanced wearable technologies.
Zinc-based composites represent promising materials for orthopedic implants owing to their adjustable degradation rates and excellent biocompatibility. In this study, a series of Zn–10Mg–xHA (x = 0–5 wt.%) composites with the core–shell structure were prepared through spark plasma sintering, and their microstructural, mechanical, and in vitro properties were systematically evaluated. Results showed that the doped hydroxyapatite (HA) is concentrated at the outer edge of the MgZn2 shell layer. The compression strength of the Zn‒10Mg‒HA composite gradually decreased with the increase of the HA content, while its corrosion rate decreased initially and then increased. The corrosion resistance of the composite with the addition of 1 wt.% HA was improved compared to that of Zn–10Mg–0HA. However, the further increase of the HA content beyond 1 wt.% resulted in a faster degradation of the composite. Moreover, the Zn–10Mg–1HA composite significantly enhanced the activity of MC3T3-E1 osteoblasts. Based on such findings, it is revealed that the composite containing 1 wt.% HA exhibits superior overall properties and is anticipated to serve as a promising candidate for bone implant materials.
Traditional lanthanide fluorides lack therapeutic efficacy against tumors, thus limiting their applications in biomedicine. In this study, we introduce a groundbreaking lanthanide-based nanomaterial known as ligand-free Ba1.4Mn0.6LuF7: Yb3+/Er3+/Ho3+ (abbreviated as BMLF). This innovative material allows for the simultaneous tuning of upconversion luminescence emissions and Fenton-like reactions through the controlled release of Mn ions within the tumor microenvironment. BMLF exhibits dual functionality through integrating ratiometric fluorescence imaging for diagnosis and nanozyme-based catalytic therapy. These capabilities are successfully harnessed for tumor theranostics in vivo. This research presents a novel approach to leveraging lanthanide fluoride nanomaterials, transforming them into fluorescent nanoenzymes with theranostic potential.
Aqueous Zn//MnO2 rechargeable zinc-ion batteries (ZIBs) possess potential applications in electrochemical energy storage due to their safety, low cost, and environmental friendliness. However, manganese dioxide as the cathode material has poor cycle stability and low conductivity. In this work, the SnO2@K-MnO2 (SMO) composite was prepared using the hydrothermal method followed by the treatment with SnCl2 sensitization, and its electrochemical characteristics were examined using SMO as the cathode material for ZIBs. The reversible specific capacity reaches 298.2 mA·h·g−1 at 0.5 A·g−1, and an excellent capacity retention of 86% is realized after 200 cycles, together with a high discharge capacity of 105 mA·h·g−1 at 10 A·g−1 and a long-term cycling life of over 8000 cycles with no apparent capacity fade. This cathode exhibits a long cycle life up to 2000 cycles at 2 A·g−1 with the mass loading of 5 mg·cm−2, and the battery maintains the capacity of 80%. The reversible co-embedding mechanism of H+/Zn2+ in such a Zn//SMO battery was confirmed by XRD and SEM during the charge/discharge process. This work can enlighten and promote the development of advanced cathode materials for ZIBs.
This study focuses on the synthesis and characterization of a thin film comprising of trimetallic sulphide, Cu2S:ZnS:NiS2. The fabrication process involved the utilization of diethyldithiocarbamate as a sulfur source, employing physical vapor deposition. A range of analytical techniques were employed to elucidate the material’s structure, morphology, and optical characteristics. The thin film exhibited a well-defined crystalline structure with an average crystallite size of 33 nm. X-ray photoelectron spectroscopy provided distinct core level peaks associated with Cu 2p, Zn 2p, Ni 2p, and S 2p. The electrochemical properties were assessed through voltammetry measurements, which demonstrated an impressive specific capacitive of 797 F·g−1. The thin film demonstrated remarkable stability over multiple cycles, establishing it as a highly promising candidate for diverse energy storage applications. In addition, comprehensive investigations were carried out to assess the photocatalytic performance of the fabricated material, particularly its efficacy in the degradation of diverse environmental pollutants. These notable findings emphasize the versatility of trimetal sulphide thin films, expanding their potential beyond energy storage and opening avenues for further research and technological advancements in fields including photocatalysis and beyond.
In recent years, research on self-healing polymers for diverse biomedical applications has surged due to their resemblance to the native extracellular matrix. Here, we introduce a novel self-healing hydrogel scaffold made from collagen (Col) and nano-hydroxyapatite (nHA) via a one-pot-synthesis approach under the influence of heating in less than 10 min. Process parameters, including the quantities of Col, guar gum, solvent, nHA, borax, and glycerol in the system were optimized for the minimization of the self-healing time. The synthesized hydrogel and polymers underwent characterization via FTIR, SEM, EDS, TGA, and 13C-NMR. Additionally, the hydrogel showed hemocompatibility with only 6.76% hemolysis at 10 µg·mL−1, while the scaffold maintained cellular metabolic activity at all concentrations for 24 h, with the optimal viability at 1 and 2.5 µg·mL−1, sustaining 93.5% and 90% viability, respectively. Moreover, the hydrogel scaffold exhibited rapid self-healing within 30 s of damage, alongside a tough and flexible nature, as indicated by its swelling rate, biodegradation under various biological pH solutions, and tensile strength of 0.75 MPa. Hence, the innovative Col and nHA self-healing hydrogel scaffold emerges as an ideal, non-toxic, cost-effective, and easily synthesized material with promising potential in cartilage repair applications.
Although Prussian blue (PB) has been widely investigated as a biocompatible photothermal agent with significant potential in cancer treatment, its further application is still hindered by low photothermal conversion efficiency (PCE) and poor stability. In this study, a biomimetic mineralization approach is employed to improve properties of PB by binding it with manganese phosphate through manganese ions, resulting in the formation of nanocomposite manganese phosphate mineralized Prussian blue (MnP&PB). Compared to PB alone, MnP&PB can significantly enhance the PCE, increasing it to 44.46%, which is attributed to the manganese-induced redshift absorption and the bandgap narrowing in the near-infrared (NIR) region. Meanwhile, MnP&PB demonstrates a significant increase in temperature compared to that of either MnP or PB alone, further enhancing the inhibition effect against cancer under the NIR irradiation. It is revealed that the incorporation of manganese phosphate into PB via biomimetic mineralization lead to the enhancement of both PCE and therapeutic efficacy, thus presenting a promising alternative approach for the improvement of cancer photothermal therapy.
The absorption of high-viscosity oil by traditional oil absorbing materials has always been a challenge. So there is an urgent need to solve the problem of slow absorption of high-viscosity oil. In this work, an emulsion composed of polydimethylsiloxane (PDMS), carbon black (CB) and waterborne polyurethane (solid content 40%) was sprayed on the melamine foam (MF). After volatilization of organic solvents, the photothermal material CB was fixed on the MF framework, making it photothermal. By raising the temperature of the modified foam to accelerate the internal thermal movement of high-viscosity oil molecules around the foam, intermolecular forces are reduced, thereby accelerating the separation process. The absorption capacity of this modified MF towards organic solvents and oil is up to 79 times its own weight. In addition, the mechanical properties of the modified foam are improved to a certain extent, more conducive to the continuous oil–water separation. This photothermal absorption material provides ideas for the rapid removal of high-viscosity oil, heavy oil, etc.
Due to high theoretical capacity and low lithium-storage potential, silicon (Si)-based anode materials are considered as one kind of the most promising options for lithium-ion batteries. However, their practical applications are still limited because of significant volume expansion and poor conductivity during cycling. In this study, we prepared a double core‒shell nanostructure through coating commercial Si nanoparticles with both amorphous titanium dioxide (a-TiO2) and amorphous carbon (a-C) via a facile sol‒gel method combined with chemical vapor deposition. Elastic behaviors of a-TiO2 shells allowed for the release of strain, maintaining the integrity of Si cores during charge‒discharge processes. Additionally, outer layers of a-C provided numerous pore channels facilitating the transport of both Li+ ions and electrons. Using the distribution of relaxation time analysis, we provided a precise kinetic explanation for the observed electrochemical behaviors. Furthermore, the structural evolution of the anode was explored during cycling processes. The Si@a-TiO2@a-C-6 anode was revealed to exhibit excellent electrochemical properties, achieving a capacity retention rate of 86.7% (877.1 mA·h·g−1 after 500 cycles at a 1 A·g−1). This result offers valuable insights for the design of high-performance and cyclically stable Si-based anode materials.
MIL-101(Cr) has a special pore cage structure that provides broad channels for the transport of water molecules in the reverse osmosis (RO) water separation and purification. Combining MIL-101(Cr) with Fe3O4 nanoparticles forms a water transport intermediate layer between the polyamide separation membrane and the polysulfone support base under an external magnetic field. MIL-101(Cr) is stable in both water and air while resistant to high temperature. With the introduction of 0.003 wt.% MIL-101(Cr)/Fe3O4, the water flux increased by 93.31% to 6.65 L·m−2·h−1·bar−1 without sacrificing the NaCl rejection of 95.88%. The MIL-101(Cr)/Fe3O4 multilayer membrane also demonstrated certain anti-pollution properties and excellent stability in a 72-h test. Therefore, the construction of a MIL-101(Cr)/Fe3O4 interlayer can effectively improve the permeability of RO composite membranes.
Combining molecular imprinting technique with titanium dioxide (TiO2) photocatalysis technique can improve the degradation ability and selectivity of TiO2 nanoparticles towards pollutants. In this work, methyl orange-imprinted polysiloxane particles (MIPs) were synthesized using TiO2 as matrix and silane as functional monomers. The adsorption capacity (Qe) of MIPs was 20.48 mg·g−1, while the imprinting efficiency (IE) was 3.4. Such MIPs exhibited stable imprinting efficiencies and adsorption efficiencies towards methyl orange (MO) in the multi-cycle stability test. Photocatalytic degradation performances of both MIPs and non-imprinted polysiloxane particles (NIPs) were investigated. Compared with NIPs, MIPs exhibited better photocatalytic degradation performance towards MO, with the degradation efficiency of 98.8% in 12 min and the apparent rate constant (Kobs) of 0.077 min−1. The interaction between silane and MO was also studied through molecular dynamics simulation. This work provides new insights into the use of silane for the synthesis of MIPs as well as the molecular imprinting technique for applications in the field of TiO2 photocatalysis.
In metal-based additive manufacturing processes, such as laser powder bed fusion (LPBF), the powder utilization is often less than 50%. Considering the cost efficiency, powder reuse is needed for an economical and sustainable LPBF process. As intermetallic compounds, LPBF-fabricated NiTi alloys are characterized with phase transformation behaviors, mechanical properties and functions that are very sensitive to possible changes in powder characteristics caused through reuse, but the exact effects are still poorly understood. Here, the LPBF process has been repeated ten times using the virgin powder supplement method. Results show that the oxygen content of NiTi powders rises from 370 to 752.3 ppm with the enhancement of the reuse cycle number. Powder oxidation enhances the laser absorptivity of the powder bed, leading to an increase in surface roughness and porosity of NiTi parts. Compared to the specimens made from virgin powders, the mechanical property and shape memory function of specimens made from reused powders are degraded, mainly attributed to the oxygen impurity and deteriorated forming quality. This study allows making better decisions with regard to powder reuse in the development of performance-critical NiTi parts fabricated through LPBF.
Cathodoluminescence (CL) characterization technology refers to a technical approach for evaluating the luminescent properties of samples by collecting photon signals generated under electron beam excitation. By detecting the intensity and wavelength of the emitted light, the energy band structure and forbidden bandwidth of a sample can be identified. After a CL spectrometer is mounted on a scanning electron microscope (SEM), functions are integrated, such as high spatial resolution, morphological observation, and energy-dispersive spectroscopy (EDS) to analyze samples, offering unique and irreplaceable advantages for the microstructural analysis of certain materials. This paper reviews the applications of SEM-CL systems in the characterization of material microstructures in recent years, illustrating the utility of the SEM-CL system in various materials including geological minerals, perovskite materials, semiconductor materials, non-metallic inclusions, and functional ceramics through typical case studies.
Copper has good electrical conductivity but poor mechanical and wear-resistant properties. To enhance the mechanical and wear-resistant properties of the copper matrix, a strategy of in-situ generation of graphene was adopted. Through ball-milling processes, a carbon source and submicron spherical copper were uniformly dispersed in a dendritic copper. Then, a uniform and continuous graphene network was generated in-situ in the copper matrix during the vacuum hot-pressing sintering process to improve the performance of composites. The graphene product exhibited lubrication effect and provided channels for electrons to move through the interface, improving the wear resistance and the electrical conductivity of composites. When the graphene content in the composite material was 0.100 wt.%, the friction coefficient and the wear rate were 0.36 and 6.36 × 10−6 mm3·N−1·m−1, diminished by 52% and reduced 5.11 times those of pure copper, respectively, while the electrical conductivity rose to 94.57% IACS and the hardness was enhanced by 47.8%. Therefore, this method provides a new approach for the preparation of highly conductive and wear-resistant copper matrix composite materials.
Titanium dioxide (TiO2) whiskers modified with octadecyltrimethoxysilane were incorporated into the coating solution through a solution blending method. The superhydrophobic coating was designed and fabricated using polyvinylidene fluoride (PVDF) and polyperfluorinated ethylene propylene (FEP) as the main constituents, while silane-modified TiO2 whiskers as the fillers. The results demonstrated that after a 360-h scaling test, the mass of CaCO3 on the surface of the resulted silane-modified superhydrophobic TiO2‒PVDF‒FEP coating was only 1.90 mg·cm−2, decreased by 37.1% and 16.7% compared with those on the PVDF‒FEP coating and the TiO2‒PVDF‒FEP coating, respectively. The synergistic effects of the air film, silane-modified TiO2 whiskers, and superhydrophobicity ensure that this superhydrophobic TiO2‒PVDF‒FEP coating has excellent scale inhibition performance. This study presents a novel approach for advancing the development of superhydrophobic coatings, offering promising prospects for industrial-scale applications in preventive measures.
Ionized amine group (R-NH2) and carboxyl group (R-COOH) within the active layer of polyamide (PA) nanofiltration membranes result in the formation of positive (R-
TC11, with a nominal composition of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si, is the preferred material for engine blisk due to its high-performance dual-phase titanium alloy, effectively enhancing engine aerodynamic efficiency and service reliability. However, in laser powder bed fusion (L-PBF) of TC11, challenges such as inadequate defect control, inconsistent part quality, and limited optimization of key processing parameters hinder the process reliability and scalability. In this study, computational fluid dynamics (CFD) was used to simulate the L-PBF process, while design of experiments (DoE) was applied to analyze the effect of process parameters and determine the optimal process settings. Laser power was found to have the greatest impact on porosity. The optimal process parameters are 170 W laser power, 1100 mm·s−1 scanning speed, and 0.1 mm hatch spacing. Stripe, line, and chessboard scanning strategies were implemented using the optimal process parameters. The stripe scanning strategy has ~33% (~400 MPa) greater tensile strength over the line scanning strategy and ~12% (~170 MPa) over the chessboard scanning strategy. This research provides technical support for obtaining high-performance TC11 blisks.
Novel advanced nanocomposites formed by associating graphene oxide (GO) nanosheets with other nanomaterials such as titanium dioxide nanoparticles, cellulose nanofibers, cellulose nanocrystals, and carbon nanotubes were incorporated in nanofiltration (NF) and reverse osmosis (RO) membranes for wastewater treatment and desalination. GO-based nanocomposite has promising potential in membrane technology due to its high hydrophilicity, absorption capacity, good dispersibility in water and organic solvents, anti-biofouling properties, and negative charge. Moreover, additional properties can be obtained depending on the nanohybrid formed. This review paper highlights the recent breakthrough in membranes functionalized with GO-based nanohybrids, focusing on membrane performance in terms of permeability, selectivity, and antifouling properties. Although GO-based nanohybrids have made significant progress in membrane technology, improvements are still needed, especially regarding trade-off effects. Furthermore, the studies presented here are limited to laboratory scale, which leads to suggestions for new studies evaluating the possibility of commercial application and the potential environmental impact caused by nanocomposites.
High solar evaporation efficiency combined with enhanced desalination and antifouling performance is key in the application of the solar-driven interfacial water evaporation (SIWE) technology. In this study, we have designed a dual-crosslinked and dual-networked hydrogel (CSH) for interfacial solar vapor generation (ISVG). Through adjusting the proportions of matrix components and balancing the degree of crosslinking between cellulose and epichlorohydrin, it is feasible to obtain the hybrid hydrogel with elastic behaviors. The resulted hydrogel has a porous structure enabling the transport of water molecules, while the doped component of iron-based metal–organic frameworks provides this hydrogel with strong light absorbance, achieving an evaporation rate of 2.52 kg·m−2·h−1 under 1 kW·m−2 solar irradiation and an evaporation efficiency of 89.32%. The porosity also creates salt resistance through capillary forces. Practical applications of such CSH hydrogels in the field of seawater desalination and wastewater purification are conducted under outdoor light conditions, and the concentrations of metal ions are revealed to be reduced by orders of magnitude below the WHO threshold ones, while pigments are found to be absent from the condensate contained in the treated wastewater.
The utilization of photocatalytic nitrogen fixation, a process celebrated for its environmental friendliness and sustainability, has emerged as a promising avenue for ammonia synthesis. The rational design of photocatalysts containing single atoms and heterojunctions has been a long-standing challenge for achieving efficient nitrogen fixation. This study innovatively constructs composite catalysts integrating single-atom copper within metal–organic frameworks (Fe-MOF, NH2-MIL-101) and carbon nitride nanosheet (CNNS). The nitrogen fixation efficiency of the Cu@MIL-CNNS heterojunction was 8 and 12 times those of the original MOF and CNNSs, respectively. Through detailed characterization, we unveil a unique charge transfer pathway facilitated by the synergy between single-atom copper and heterojunctions, highlighting the critical function of copper centers as potent active sites. Our findings underscore the transformative potential of single atomic sites in amplifying charge transfer efficiency, propelling advancements in the photocatalyst design.
Electrospinning has been widely used in the field of biomedical materials characterized with high porosity and good breathability as well as similarity to the natural extracellular matrix. This study employs the microsol-electrospinning technology combined with the self-induced crystallization method to fabricate the functionalized bilayer poly(ε-caprolactone) (PCL) fibrous membrane with a shish-kebab (SK) structure. The outer layer consists of the antibacterial SK-structured fibrous membrane showing favorable mechanical properties and notable inhibitory effects on the growth of E. coli and S. aureus, while salvianic acid A sodium (SAS) is encapsulated in the inner core‒shell and SK-structured PCL fibrous membrane, achieving the controlled and sustained release of SAS. Moreover, good biocompatibility and enhanced cell adhesion of this membrane are also revealed. This antibacterial and drug-loaded bilayer PCL fibrous membrane with a SK structure demonstrates superior mechanical characteristics, exceptional antibacterial properties, and notable biocompatibility, suggesting its favorable outlook for future development in the area of tissue engineering.
It is undoubtedly a challenge to design an efficient and recyclable photocatalyst for the degradation of tetracycline (TC). In this study, a MoS2@C composite catalyst was fabricated through the simple sulfurization of alginate-based spheres encapsulating ammonium molybdate by thiourea. The incorporation of porous carbon as a co-catalyst significantly augmented reactive active sites, endowing it with great specific surface area and effectively preventing the aggregation of MoS2 nanoparticles. While offering abundant catalytic sites for the reaction, the structure with interconnected channels promoted the adsorption of the reactant. The MoS2@C composites showed excellent photocatalytic performance, achieving a photodegradation ratio of 87.01% for TC within 60 min, superior to that of pure MoS2. Additionally, the photocatalytic mechanism for the degradation of TC was also investigated through free radical trapping experiments in combination with the electron spin resonance technique.
With the accelerated development of urbanization, it is urgent to develop new green and effective fungicides for water disinfection, which can effectively sterilize without causing bacterial drug resistance and environmental burden. In this work, the new ternary nanofiber (NF) heterojunctions, Ag/ZnO/g-C3N4 (Ag/ZCN), with high specific surface area were controllably fabricated through the photodeposition of different amounts of Ag quantum dots on electrospun ZCN NFs. Ag/ZCN with 6 wt.% Ag was found to exhibit the highest antibacterial activity superior to that of ZCN and ZnO NFs, which completely killed E. coli or S. aureus within 30 min under solar light. Moreover, it maintained high stability during four consecutive photocatalytic cycles. The photocatalytic Z-scheme charge transportation mechanism of Ag/ZCN was confirmed through structure characterization and free radical capture experiments. It was verified that the active oxygen substances such as ∙OH, 1O2, and a certain amount of ∙O2− were mainly produced in the photocatalytic sterilization process. Therefore, the Z-scheme NF heterojunction Ag/ZCN has great application potential in actual environmental water disinfection.
Calcium ion-crosslinked alginate hydrogels are widely used as a materials system for investigating cell behavior in 3D environments in vitro. Suspensions of calcium sulfate particles are often used as the source of Ca2+ to control the rate of gelation. However, the instability of calcium sulfate suspensions can increase chances of reduced homogeneity of the resulting gel and requires researcher’s proficiency. Here, we show that ball-milled calcium sulfate microparticles (MPs) with smaller sizes can create more stable crosslinker suspensions than unprocessed or simply autoclaved calcium sulfate particles. In particular, 15 µm ball-milled calcium sulfate MPs result in gels that are more homogeneous with a balanced gelation rate, which facilitates fabrication of gels with consistent mechanical properties and reliable performance for 3D cell culture. Overall, these MPs represent an improved method for alginate hydrogel fabrication that can increase experimental reliability and quality for 3D cell culture.
We present an interesting low-cost, green, and scalable technique for direct ink writing for flexible electronic applications different from traditional fabrication techniques. In this work, a reduced graphene oxide (RGO)‒bismuth oxide (Bi2O3)/carbon nanotube (CNT) (RGBC) ternary conductive ink was prepared by an initial synthesis of RGO‒Bi2O3 (RGB) via a hydrothermal method. This was followed by the fabrication of conductive ink through homogenous mixing of the binary nanocomposite with CNTs in a mixture of ethanol, ethylene glycol, glycerol, and double-distilled water as the solvent. Electronic circuits were fabricated through directly writing the prepared ink on flexible nanocrystalline cellulose (NCC) thin film substrates. The nanocomposites consisted of rod-shaped nanoparticles that were grown on the surface of the nanographene sheet. The semiconductor nanocomposite exhibited excellent conductivity and further confirmed by applying it as an electrode in the electrical circuit to light a light-emitting diode (LED) bulb. The highest electrical conductivity achieved was 2.84 × 103 S·m−1 with a contact angle of 37°. The electronic circuit written using the conductive ink exhibited good homogeneity, uniformity, and adhesion. The LED experiment demonstrates the good conductivity of the electroconductive circuit and prepared ink. Hence, the NCC substrate and RGBC conductive ink showcase an excellent potential for flexible electronic applications.
Conventional metal-oxide-semiconductor (MOS) gas sensors are limited in wearable gas detection due to their non-flexibility, high operating temperature, and less durability. In this study, a yarn-based superhydrophobic flexible wearable sensor for room-temperature ammonia gas detection was prepared based on the nano-size effect of both nanocore yarns prepared through electrostatic spinning and MOS gas-sensitive materials synthesized via a two-step hydrothermal synthesis approach. The yarn sensor has a response sensitivity of 13.11 towards 100 ppm (1 ppm = 10−6) ammonia at room temperature, a response time and a recovery time of 36 and 21 s, respectively, and a detection limit as low as 10 ppm with the sensitivity of up to 4.76 towards ammonia. In addition, it displays commendable linearity within the concentration range of 10‒100 ppm, accompanied by remarkable selectivity and stability, while the hydrophobicity angle reaches 155.74°. Furthermore, its sensing performance still maintains stability even after repeated bending and prolonged operation. The sensor also has stable mechanical properties and flexibility, and can be affixed onto the fabric surface through sewing, which has a specific potential for clothing use.
A novel and eco-friendly ethyl acetate/water solvent system was employed to create stable water-in-oil (W/O) emulsions of curcumin (Cur)-loaded poly(ε-caprolactone) (PCL)/bovine serum albumin (BSA) without the need for surfactants. The size of emulsion droplets decreased with the rise of the BSA concentration but increased with the drop of the oil-to-water (OTW) volume ratio. Upon electrospinning, the morphology of Cur-loaded PCL/BSA composites transformed from bead-like structures to uniform fibers as the BSA concentration rose from 0% (w/v) to 10% (w/v). With the enhancement of the OTW volume ratio, the composite fibers displayed an increased diameter and a consistently uniform morphology. The highest modulus of elasticity (0.198 MPa) and the largest elongation at break (199%) of fibers were achieved at the OTW volume ratio of 7:3, while the maximum tensile strength (3.83 MPa) was obtained at 8:2. Notably, the presence of BSA resulted in the superhydrophilicity of composite fibers. Moreover, all composite fibers exhibited sustained drug release behaviors, especially for those with the OTW volume ratio of 7:3, the release behavior of which was the best to match the first-order model. This study is expected to improve biofunctions of hydrophobic PCL and expand its applications in biomedical fields.