Flexibility Properties Research Articles

Conformational Flexibility and Net Charge are Key Determinants for the Antimicrobial Activity of Peptide Uy234 Against Multidrug-resistant Bacteria

BackgroundThe antimicrobial activity of two peptides, Uy234 derived from the venom of the scorpion Urodacus yaschenkoi and a consensus peptide QnCs-Buap, was evaluated. We tested different pathogenic bacteria: Acinetobacter baumannii, Klebsiella pneumoniae, Salmonella enterica, Bacillus subtilis, Enterococcus spp. and Staphylococcus aureus, including one methicillin resistant (MRSA) and two multidrug resistant (MDR) clinical isolates. In contrast to the QnCs-Buap peptide, Uy234 showed relevant growth inhibitory activity on A. baumannii and B. subtilis, and mostly on S. aureus strains.ObjectiveThe present research focused on elucidating the mechanism for this antibacterial activity.MethodologyWe carried out an in-depth analysis of the composition, structure, flexibility, and physicochemical properties of both peptides.ResultsWe found a crucial role of the C-terminal amide and composition in favoring the formation of a dense H-bond network in the Uy234 peptide. This H-bonding network slightly stiffens the peptide and keeps it in a preordered conformation in the aqueous phase.ConclusionsWe hypothesize that, given that Uy234 is a very short peptide (18 aa), it could have a destabilizing effect and favor micellization phenomena instead forming pores. In contrast, the QnCs-Buap peptide (13 aa), having only the positive charge at the N-terminal end and being significantly more hydrophobic and rigid, is not capable of overcoming the energy barrier to disturb the membrane. We propose that Uy234 peptide can be a scaffold to develop new derivatives with high potential against infections caused by diverse multidrug-resistant bacteria.Graphical

Flexibility, Dispersion Property, and Giant Sunlight Absorption of Monolayer MX2 (M = Zr, Hf; X = S, Se) and Related Janus MXY (M = Zr, Hf; X = S, Y = Se)

IVB–VIA transition metal dichalcogenides (TMDs) MX2 (M = Zr, Hf; X = S, Se) and related Janus MXY (M = Zr, Hf; X = S, Y = Se) have garnered significant attention due to their unique optoelectronic properties. To further explore their potential in flexible photonics, their mechanical, band dispersion, and optical dielectric properties using orbital hybrid theory are investigated. The results reveal that the out‐of‐plane linear compression resistance of these materials is considerably lower than their in‐plane resistance, primarily because van der Waals interactions are much weaker compared to ionic bond interactions. This characteristic makes them less susceptible to external pressure and torsional forces, positioning them as promising candidates for flexible optoelectronic devices. Furthermore, the presence of multiple energy bands at the same momentum state suggests a tendency toward metal–insulator transitions. Notably, the materials exhibit a high photon flux, indicating robust photoelectric conversion capabilities, making them suitable for applications in photoelectric transducers. This study not only deepens the understanding of the optoelectronic and mechanical properties of IVB–VIA TMD materials, but also offers theoretical guidance for the development and application of flexible optoelectronic devices based on IVB‐VIA TMDs and related Janus materials.

Polymer-Based Optical Guided-Wave Biomedical Sensing: From Principles to Applications

Polymer-based optical sensors represent a transformative advancement in biomedical diagnostics and monitoring due to their unique properties of flexibility, biocompatibility, and selective responsiveness. This review provides a comprehensive overview of polymer-based optical sensors, covering the fundamental operational principles, key insights of various polymer-based optical sensors, and the considerable impact of polymer integration on their functional capabilities. Primary attention is given to all-polymer optical fibers and polymer-coated optical fibers, emphasizing their significant role in “enabling” biomedical sensing applications. Unlike existing reviews focused on specific polymer types and optical sensor methods for biomedical use, this review highlights the substantial impact of polymers as functional materials and transducers in enhancing the performance and applicability of various biomedical optical sensing technologies. Various sensor configurations based on waveguides, luminescence, surface plasmon resonance, and diverse types of polymer optical fibers have been discussed, along with pertinent examples, in biomedical applications. This review highlights the use of biocompatible, hydrophilic, stimuli-responsive polymers and other such functional polymers that impart selectivity, sensitivity, and stability, improving interactions with biological parameters. Various fabrication techniques for polymer coatings are also explored, highlighting their advantages and disadvantages. Special emphasis is given to polymer-coated optical fiber sensors for biomedical catheters and guidewires. By synthesizing the latest research, this review aims to provide insights into polymer-based optical sensors’ current capabilities and future potential in improving diagnostic and therapeutic outcomes in the biomedical field.

Electrochromic Covalent Organic Framework-Assembled Nanofibrous Membranes with Mimetic Chameleon Skin Architectures for Visible and Near-Infrared Camouflage Stealth.

The developments of modern surveillance technology pose great challenges to combat concealment for warfighters. Traditional camouflage suits cannot accommodate the need for camouflage stealth in complex warfare scenarios. Herein, a bidirectional diffusion-controlled in situ synthesis methodology is reported to achieve electrochromic nanofibrous membranes with mimetic chameleon skin structures (CSENs) by assembling electrochromic covalent organic frameworks on nanofibers. CSENs exhibit reversible color changes in the visible and near-infrared ranges under an applied potential with fast response times (25.8 s/26.2 s). The macro- and mesoporous structures in CSENs favored the transportation of electrolyte ions, achieving excellent color difference and coloration efficiency of 35.58 and 1053.26 cm2/C, respectively. Importantly, CSENs feature unique properties of self-standing, breathability, and flexibility, which are attributed to the micrometer pores constructed by entangled nanofibers. As a proof-of-concept study, the CSEN-based flexible electrochromic suit exhibits a dynamic camouflage function in real environments, showing promising properties as smart textiles for dynamic camouflage stealth.

Realization of an Optimized Cylindrical Uniform Magnetic Field Coil via the Flexible Printed Circuit Technology

Abstract The design and fabrication method of magnetic field coils with high uniformity is essential for atomic magnetometers. In this paper, a novel design strategy for cylindrical uniform coils is first proposed, which combines the target-field method (TFM) with an optimized slime mold algorithm (SMA) to determine optimal structure parameters. Then, the realization method for the designed cylindrical coil by using the flexible printed circuit (FPC) technology is presented. Compared with traditional fabrication methods, this method has advantages in excellent flexibility and bending property, making the coils easier to be arranged in limited space. Moreover, the manufacturing process of the FPC technology via a specific cylindrical uniform magnetic field coil is discussed in detail, and the successfully realized coil is well tested in a verification system. By comparing the uniformity performance of the experimental coil with the simulation one, the effectiveness of the FPC technology in producing cylindrical coils has been well validated.

Phenothiazine-Based Organic Single Crystal with Flexibility, Piezochromism, and Fluorescent Waveguide Properties

Phenothiazine-Based Organic Single Crystal with Flexibility, Piezochromism, and Fluorescent Waveguide Properties

Electrostatic self‐assembly of barnacle‐like modified BN@ND hetero‐structured fillers to synergistic enhanced thermal conductivity of PI composite films

AbstractHigh‐integration microelectronic equipment cannot dissipate heat for long periods of time, which enormously damages the efficiency and service life of electronic devices. Developing polymer‐based composite film exhibiting admirable thermal conductivity (TC), mechanical, dielectric and insulation performances has been pursued by researchers. Polyimide (PI) materials are generally used in progressive electronic systems. In this research, we constructed unique thermally conductive fillers to improve the TC of PI composites. Specifically, boron nitride nanosheets (BNNS) and nanodiamond (ND) were modified to impart them different charging properties. The barnacle‐like hetero‐structured fillers (MBN@FND) were assembled by electrostatic self‐assembly, and then introduced into PI to prepare PI composites. MBN@FND‐2 (MBN/FND, 1/1, wt/wt) fillers exhibited optimal morphology. The results showed that MBN@FND formed tightly stacked structure in composites, availing the densification of the thermal network and improving the heat transfer efficiency. Under 25 wt% MBN@FND loading, the in‐plane TC of MBN@FND/PI composite was 9.73 W/mK, and the through‐plane TC was 0.72 W/mK. The MBN@FND/PI composite remained at a low level in terms of dielectric properties. Moreover, MBN@FND/PI composites had flexibility, good tensile strength (47.9 MPa), and volume resistivity of 1.05 × 1013 Ω cm. This work provides a versatile approach for the preparation of hybrid materials.Highlights Hetero‐structured fillers were prepared by electrostatic self‐assembly. The in‐plane TC and through‐plane TC of PI composite was improved. The composites had insulation, flexibility, and low dielectric properties.

Wood Cell Wall Nanoengineering toward Anisotropic, Strong, and Flexible Cellulosic Hydrogel Sensors.

Achieving highly ionic conductive hydrogels from natural wood remains challenging owing to their insufficient surface area and low number of active sites on the cell wall. This study proposes a viable strategy to design a strong and anisotropic wood-based hydrogel through cell wall nanoengineering. By manipulating the microstructure of the wood cell wall, a flexible cellulosic hydrogel is achieved through Schiff base bonding via the polyacrylamide and cellulose molecular chains. This results in excellent flexibility and mechanical properties of the wood hydrogel with tensile strengths of 22.3 and 6.1 MPa in the longitudinal and transverse directions, respectively. Moreover, confining aqueous salt electrolytes within the porous structure gives anisotropic ionic conductivities (19.5 and 6.02 S/m in the longitudinal and transverse directions, respectively). The wood-based hydrogel sensor has a favorable sensitivity and a stable working performance at a low temperature of -25 °C in monitoring human motions, thereby demonstrating great potential applications in wearable sensor devices.

Research on the development and performance of flexible protective fabrics with knitted structure

Personal protective textiles (PPTs) protect humans from sharp objects. However, PPTs are designed primarily for protective performance, and their stiff material and single function make them unsuitable for long-term wear. In this study, we developed flexible protective textiles using advanced flat knitting technology. These textiles offer excellent cut resistance, good abrasion resistance, high flexibility, and warmth-retention properties. A flexible protective fabric (FPF) with knitted structure was designed with an outer layer that provides cut and abrasion resistance, an intermediate layer, and an inner layer for heat storage. The study examined the cut resistance, abrasion resistance, flexibility, thermal management, breathability and stability of the developed fabrics. FPF has excellent abrasion and cut resistance. The cut resistance of the fabric was tested in three directions. The warp cutting load was 2145 gf, while the weft cutting load was 2347 gf. The diagonal cutting load was the largest at 2364 gf, resulting in an A5 cutting grade for high cutting hazards. Compared with other protective fabrics available on the market, FPF stands out due to its softness and the smallest bending stiffness in both the warp and weft directions. Additionally, it has excellent thermal management performance and breathability, providing 53% insulation and 146 mm/s breathability. Stability tests have shown that FPF has excellent color fastness to perspiration, good cleaning stability and aging stability for cut resistance, flexibility, warmth-retention properties and breathability.

Water-Rewritable Structural Color Textiles with Fast Response Speed and Antispreading Capability.

The stimuli-responsive textiles, especially water-responsive textiles, have garnered attention owing to their environmental compatibility. Inspired by the hydrochromic behavior of Diphylleia grayi, water-rewritable structural color (WRSC) textiles exhibiting fast response speed and antispreading capability were fabricated by spraying hollow SiO2 (H-SiO2) microspheres and poly(trifluoroethyl methacrylate-butyl acrylate) [P(TFEMA-BA)]. The water-written textiles exhibited structural color changes in 0.6 s via an increase in the refractive index, driven by water penetrating the gaps between H-SiO2 microspheres. The structural color was restored to the initial state after the water evaporated, allowing multiple cycles of the write-erase-write mode. The hydrophobic P(TFEMA-BA) adhesive was used to construct a stable chromogenic array and endow WRSC textiles with antispreading properties, thereby improving structural stability and achieving clear writing patterns. The prepared WRSC textiles demonstrated high flexibility, structural stability, and water-rewritable properties, providing advanced bionic inspiration and valuable design ideas for rewritable materials and smart textiles.

Improved qualities of cod-rice dual-protein gel as affected by rice protein: Insight into molecular flexibility, protein interaction and gel properties

Blending plant-based proteins with animal-based proteins to achieve adequate dietary protein intake is a strategy to address dietary deficiencies in the elderly. This research systematically investigated the effect of the ratio of cod protein/rice protein (21:0, 21:1.5, 21:3, 21:4.5, 21:6, 21:7.5, and 21:9) on the gelation properties of dual-protein gels and the underlying dual-protein interaction mechanisms. The results indicated that the myosin heavy chain (MHC) of cod and the glutelin in rice protein are primarily linked by hydrogen bonds, particularly involving Tyr residues, as evidenced by molecular docking and fluorescence quenching results. The addition of rice protein in cod protein promoted α-helix transforming into β-sheet, β-turn and random coil of the original protein solution, which was significantly correlated with molecule flexibility increasing. The decrease in the dual-protein particle size, and rice protein uniformly distributed in a cod protein-based gel network, which promoted the compactness and density of the gel structure. It was found that the hardness and springiness of 21:6 cod-rice protein gel increased by 73.96% and 17.28% compared to single cod gel, respectively. This study provides theoretical basis to the mechanism of dual-protein interaction affecting gel properties from the molecular level.

Fabrication of highly flexible biopolymeric chitosan/agarose based bioscaffold with Matricaria recutita herbal extract for antimicrobial wound dressing applications

A flexible biopolymer-based antimicrobial wound dressing has the potential to alleviate the burden of bacterial infections in wounds by enhancing antimicrobial effectiveness and promoting faster wound healing. This study focuses on the development of a highly flexible chitosan-agarose (CS-AG) bioscaffold, incorporating Matricaria recutita chamomile flower extract (CH) through a conventional casting method. The flexible CS-AG bioscaffold's physiochemical properties were confirmed by FTIR, indicating secondary interactions, and XRD, showing its crystalline structure. The addition of CH to the optimized CS-AG bioscaffold resulted in significant tensile strength (17.28 ± 0.33 MPa), distinctive structural morphology (SEM), surface roughness (AFM), contact angle, improved thermal properties (DSC), and enhanced thermal stability (TGA). Furthermore, the CH-infused bioscaffold significantly increased swelling capacity (~81.09 ± 1.74 % over 48 h), and degradation profile (~52 % over 180 h). The release studies of CS-AG-CH bioscaffold demonstrate controlled release of CH with in the bioscaffold at different pH conditions. The bioscaffold demonstrated effective antibacterial activity against S. aureus and E. coli strains. Additionally, cytotoxicity assays indicated that the bioscaffold supports better cell viability and proliferation in fibroblast (NIH 3T3) cell lines. Consequently, this antimicrobial bioscaffold shows promise as a drug release system and biocompatible wound dressing suitable for tissue engineering applications.

Estimation the Properties of Polymer Matrix Reinforced with Plants Extract Used for Medical Fluid Bags

Abstract The utilize of polyvinyl chloride in the manufacturing of blood bags responsible for preserving blood. It attains an extensive range of performance and processing requirements such as flexibility, transparency, physical, antibacterial and non-hemolysis properties. So, in the present flax-seed gel was incorporated in PVC matrix at various concentration (1, 2 and 3) %. Then wheat extract was added to samples has better properties in two percentage (0.5 and 1) %. The obtained results show, a significant change in the properties of the composite produce, where the tensile strength increased with increasing concentration of extract from flax seed gel, but it decreased when wheat extract was added, and when both extracts were added, the inhibition zone increased against bacterial activity for two types of bacteria (S. aureus and C. albicans). Also, the ability to absorb water and wettability increased with increasing concentration of plant extracts. On the other hand, the transparency decreased with increasing concentration of flaxseed gel, but when wheat gel was added to it increase of transparency. All samples were non-hemolytic in hemolysis test.

Enhanced electrochemical performance of flexible carbon substrates via carbonized layer of oxidant-induced polydopamine for high-performance supercapacitors

Flexible substrates are essential for advancing energy storage materials in portable and wearable devices. Carbon cloth is a promising option due to its flexibility and lightweight properties, but its high electrical resistance and hydrophobic surface present challenges for solution-based electrolytes. To overcome these issues, a surface modification technique was developed that coats carbon cloth with dopamine and subsequently carbonizes it. This process enhances hydrophilicity while preserving the sp2 carbon structure, significantly improving electrical conductivity. The chemical bath deposition of Ni(OH)2 onto the carbonized polydopamine-coated carbon cloth produced a uniform layer that increased specific capacitance dramatically. At a current density of 1 A/g, the specific capacitance reached 1100F/g, compared to 919F/g for Ni(OH)2 on unmodified carbon cloth. Furthermore, the electrodes maintained high specific capacitance at higher current densities, showcasing superior rate capability. Overall, carbonized polydopamine layers effectively reduce electrical resistivity and hydrophobicity, enhancing the performance of carbon-based materials for energy storage applications.

Sustained-release composite films incorporated with cinnamon essential oil: Characterization, release kinetics and application for cherry tomato preservation

Food spoilage waste accelerated the development of bio-based active food packaging. Sustained-release composite films based on oxidized corn starch/ pullulan were prepared by incorporating cinnamon essential oil (CEO) nanoemulsion. The SEM, ATR-FTIR and XRD results showed that CEO was successfully encapsulated in film matrixes. The composite films exhibited the increase of thermal stability, UV-shielding, flexibility and water vapor resistance properties. The films containing CEO nanoemulsion (≥10%) showed excellent antimicrobial activities against S. aureus, E. coli and B. cinerea (the maximum inhibition zones achieving 27.23 ± 2.31 mm). The release kinetics results showed sustained release of CEO from the films with high content of CEO nanoemulsion, and the dominant release mechanism was Fickian diffusion. The composite films effectively maintained cell structure, weight, firmness and total soluble solids content of fruits during storage. Therefore, the sustained-release composite films could be a prospective packaging material for fruits preservation.

Flexible and Flame Retardant Cotton Fiber-reinforced CS/CNF/EP Composites For a Sensitive Fire Warning

Enhancing fire safety performance in resin-based composites is critical for mitigating fire hazards. Composites that provide early warnings during initial fire stages and maintain prolonged alarm capabilities under flame exposure are essential for minimizing injuries and property damage. This study employs chitosan (CS) as a cross-linking and char-forming agent, while carbon nanofiber (CNF) acts as a flame retardant and conductive component. Cotton fiber-reinforced chitosan/carbon nanofiber composites with varying epoxy and CNF contents (CS/CNF/EP) were prepared through a straightforward low-temperature curing process (40 °C, 4 h). Crosslinking polymerization between chitosan and epoxy was confirmed via Fourier Transform Infrared Spectroscopy (FTIR). The presence of the tough structure of CS and the rigid structure of EP results in a synergistic toughening and reinforcement effect in the CS/CNF/EP composites. Additionally, due to the carbon facilitating properties of CS and the enhanced conductivity of CNF, the composites exhibit a sensitive fire alarm functionality. At 35 % epoxy content, the CS/CNF/EP composites demonstrated exceptional properties, including mechanical flexibility (tensile strength of 7.09 MPa and breaking elongation of 129.05 %) and outstanding flame retardancy (LOI of 32.3 % and UL-94 V-0 rating). These composites provided a rapid alarm (∼1 s), sustaining a 263 s warning under flame exposure and over 35 min post-flame removal. These findings indicate that CS/CNF/EP composites, integrating mechanical flexibility, flame retardancy, and superior fire warning properties, present significant potential applications in fire safety engineering.

Two-dimensional MXene Nanosheets and their Composites for Antibacterial Textiles: Current Trends and Future Prospects

Abstract: As a novel two-dimensional (2D) nanosheet (NS), MXene has attracted attention in antibacterial applications due to its excellent high surface area, remarkable hydrophilicity, strong flexibility, and excellent antibacterial properties. This review intends to provide valuable insight into the further development of antibacterial MXenes and their composite materials. In this paper, we review the antibacterial mechanisms of MXenes and their composite materials and summarize the research progress of antibacterial finishing fabrics, fibers and dressings based on MXene NSs. Due to the rich oxygen-containing groups, 2D MXene NSs and its composites exhibited significant antibacterial activity against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis so they have been widely used in antibacterial textiles including finishing fabrics, fibers, and dressings. 2D MXene NSs have showed some antibacterial properties based on cell experiments or blood tests. The antibacterial mechanisms mainly include physical sterilization and chemical oxidative stress sterilization. The future direction of antibacterial textiles based on MXenes was proposed.

Fabrication and characterization of long-lasting antifungal film containing cinnamaldehyde-loaded complex coacervation microcapsules based on gelatin and gum Arabic

A novel long-acting antifungal active film was successfully created, as an alternative to conventional chemical food preservatives. The antifungal films incorporated with cinnamaldehyde (CA) microcapsules achieved long-lasting antifungal activity, mitigated yellowing caused by the direct addition of CA, and showed improved flexibility properties. CA multinuclear microcapsules were produced using gelatin with a Bloom value of 200 and gum arabic, resulting in increased encapsulation efficiency (99.86 %), good dispersibility and enhanced antifungal ability (inhibition zone diameter of 32 mm). These microcapsules can be incorporated into films as a sustained-release antifungal agent. Compared to unencapsulated CA, the addition of 1 % CA microcapsules reduced the ultraviolet transmittance (<36.40 %) of the film while maintaining visible-light transmittance (36.40 %–65.20 %), and improving its elongation at break (23.49 %). The water vapor permeability of the film was not affected by the inclusion of CA microcapsules below 0.25 %. Moreover, microcapsules can enhance the thermal properties of the film. Antifungal films incorporated with 0.5 %–2 % microcapsules may offer better long-acting inhibition against A. brasiliensis. This study presents a new promising pathway for food storage.

Flexible Single Microwire X-Ray Detector with Ultrahigh Sensitivity for Portable Radiation Detection System.

Sensitive, flexible, and low false alarm rate X-ray detector is crucial for medical diagnosis, industrial inspection, and scientific research. However, most semiconductors for X-ray detectors are susceptible to interference from ambient light, and their high thickness hinders their application in wearable electronics. Herein, a flexible visible-blind and ultraviolet-blind X-ray detector based on Indium-doped Gallium oxide (Ga2O3:In) single microwire is prepared. Joint experiment-theory characterizations reveal that the Ga2O3:In microwire possess a high crystal quality, large band gap, and satisfactory stability, and reliability. On this basis, an extraordinary sensitivity of 5.9×105µCGyair -1cm-2 and a low detection limit of 67.4nGyairs-1 are achieved based on the prepared Ag/Ga2O3:In/Ag device, which has outstanding operation stability and excellent high temperature stability. Taking advantage of the flexible properties of the single microwire, a portable X-ray detection system is demonstrated that shows the potential to adapt to flexible and lightweight formats. The proposed X-ray detection system enables real-time monitor for X-rays, which can be displayed on the user interface. More importantly, it has excellent resistance to natural light interference, showing a low false alarm rate. This work provides a feasible method for exploring high-performance flexible integrated micro/nano X-ray detection devices.

DFT Study on the Second-Order NLO Responses of 2-Phenyl Benzoquinoline Ir(III) Complexes by Substituents and Redox Effects.

Metal complexes have received extensive attention in nonlinear optical (NLO) materials because of their advantages, such as shorter response times and more flexible structural properties. Density functional theory is used in investigating the geometric structures, electronic structures, charge centroid, and first hyperpolarizability (βtot) of a series of selected 15 coordinated Ir(III) complexes. The substitute effect and one-electron redox process effects on the structures and properties of 15 coordinated Ir(III) complexes are considered. When the electron-withdrawing group is introduced into the ligand, the HOMO-LUMO energy gap decreases and the βtot value increases, positively correlating with the electron-withdrawing ability. The single electron redox process can also improve the NLO responses of complexes, especially the reduction process. The βtot value of complex 4- is the largest, 2078 times higher than that of complex 4. The analysis shows that the variation of NLO responses of complexes is ascribed to the change of electronic structures and the charge transfer modes induced by the ligand modification and redox process, which are considered to be two effective methods in enhancing the NLO responses of 2-phenyl benzoquinoline Ir(III) complexes. This study aims to offer design insights into high-performance nonlinear optical materials.