Fluorescent Fibers Research Articles

Fluorescent poly(ethylene terephthalate) nanofibers membrane for aqueous copper ions detection

The contamination of heavy metal ions in water resources poses a threat to both human health and the environment. Fluorescent sensing technologies based on rare earth elements can be widely applied for the accurate detection and quantitative analysis of metal ions. A fluorescent nanofiber membrane material with sensitivity to copper ions was developed. The Eu(TTA)3·2H2O complex was formed through a complexation reaction between europium (Eu) and 2-thenoyltrifluoroacetone (TTA). This complex was then co-spuned with a solution of PEG-modified PET (GPET) using the centrifugal electrostatic spinning method to create a fluorescent PET fiber membrane (GPET@Eu-NFM). Results show that the fluorescence intensity of GPET@Eu-NFM is enhanced compared to the Eu(TTA)3·2H2O complex. As the concentration of the copper ion solution increases, the fluorescence intensity of the film presents a linear decreasing trend, and it also has a linear relationship with pH. This indicates that the fluorescent polyester fiber membrane exhibits dual responsiveness to copper ions and pH. An effective, quick, and convenient method for the monitoring and analysis of copper ions can be proposed by utilizing the fluorescence quenching phenomenon observed when the super hydrophilic surface of functionalized GPET@Eu-NFM comes into contact with copper ions.

An improved calibration procedure for accurate plastic scintillation dosimetry on an MR-linac.

Plastic scintillation dosimeters (PSDs) are highly suitable for real-time dosimetry on the MR-linac. For optimal performance, the primary signal (scintillation) needs to be separated from secondary optical effects (Cerenkov, fluorescence and optical fiber attenuation). This requires a spectral separation approach and careful calibration. Currently, the 'classic' calibration is a multi-step procedure using both kV and MV X-ray sources, requiring an uninterrupted optical connection between the dosimeter and read-out system, complicating efficient use of PSDs. Therefore, we present a more time-efficient and more practical novel calibration technique for PSDs suitable for MR-linac dosimetry.
Approach: The novel calibration relies on prior spectral information combined with two 10x10 cm2field irradiations on the 1.5 T MR-linac. Performance of the novel calibration technique was evaluated focusing on its reproducibility, performance characteristics (repeatability, linearity, dose rate dependency, output factors, angular response and detector angle dependency) and IMRT deliveries. To investigate the calibration stability over time, prior spectral information up to 315 days old was used. To quantify the time efficiency, each step of the novel and classic calibration was timed.
Main results: The novel calibration showed a high reproducibility with a maximum relative standard deviation of 0.3%. The novel method showed maximum differences of 1.2% compared to the gold-standard calibration, while reusing old classic calibrations after reconnecting fibers showed differences up to 3.0%. The novel calibration improved time efficiency from 105 to 30 minutes compared to the classic method.
Significance: The novel calibration method showed a gain in time efficiency and practicality while preserving the dosimetric accuracy. Therefore, this method can replace the traditional method for PSDs suitable for MR-linac dosimetry, using prior spectral information of up to a year. This novel calibration facilitates reconnecting the detector to the read-out system which would lead to unacceptable dosimetric results with the classic calibration method.

Laser-Controlled Information Releasing and Hiding Based on Perovskite Phosphors.

Laser-active interference with high confidentiality and convenience opens up a cutting-edge path for releasing and hiding key targets; however, its development still faces enormous challenges owing to the difficulty of concealing objects. Herein, a novel conceptual design for laser-controlled information release and hiding (LIRH) is proposed and successfully realized. Cs2NaInCl6:Er3+, Yb3+ (CNIC:Er, Yb) perovskite microcrystal is adopted as a carrier for LIRH implementation, exhibiting excellent up-conversion (UC) emission under NIR (980 and 1530 nm) irradiation due to its ultralow phonon energy. The fluorescence intensity crossover and outstanding photon output capacity are revealed in comparison with Er3+/Yb3+ codoped and Er3+ single-doped CNIC phosphors under different laser sources, and the obvious difference in quantum yields (QY) under 980 and 1530 nm excitation provides theoretical possibility for LIRH. More importantly, the obtained LIRH features high stability at temperatures up to 413 K, showing good adaptability in various potential scenarios. Moreover, CNIC:Er, Yb is further combined with polyacrylonitrile (PAN) polymer to form fluorescent fibers with exceptional crystal stability and composite flexibility, thus making the LIRH code a reality based on perovskite composite phosphors. The laser-active invisibility offers an innovative idea for LIRH, further extending the application of LIRH in the field of information encryption, which has promising prospects in information safety, advanced anticounterfeiting, and smart responsive materials.

Wet-spinning fabrication of stretchable multicolor fluorescent fibers augmented with dual-state emissive dyes

Flexible luminous fibers have attracted wide attention in the field of functional and smart textiles. In this work, stretchable multicolor fluorescent fibers were successfully prepared by wet-spinning using thermoplastic polyurethane (TPU) and the boron ketoimine fluorophores (TPA-BKI dyes). Due to the donor (D)-acceptor (A) push-pull electronic system and highly twisted triphenylamine (TPA) skeleton, TPA-BKI dyes exhibited bright emission in both solution and solid states. Meanwhile, the polymer chains further improved the emission efficiency of TPA-BKI dyes in TPU matrix by avoiding close contact between dye molecules, as well as preventing intramolecular rotations in the excited states. Wet-spinning can be used for large-scale and continuous preparation of fluorescent fibers. The TPA-BKI/TPU fibers showed excellent flexibility, high mechanical strength, and bright multicolor fluorescent emission (green, yellow, and red, respectively) when the dye content was as low as 0.1 wt%. Overall, the feasibility of large-scale preparation of fluorescent fibers and their excellent properties, such as flexibility, multicolor fluorescence, and mechanical stability, make them suitable for potential applications, including clothing displays, fashion designs, security, and anti-counterfeiting.

Super‐Strong, Super‐Stiff, and Super‐Tough Fluorescent Alginate Fibers with Outstanding Tolerance to Extreme Conditions

AbstractThe combination of multiple physical properties is of great importance for widening the application scenarios of biomaterials. It remains a great challenge to fabricate biomolecules‐based fibers gaining both mechanical strength and toughness which are comparable to natural spider dragline silks. Here, by mimicking the structure of dragline silks, a high‐performance fluorescent fiber Alg‐TPEA‐PEG is designed by non‐covalently cross‐linking the polysaccharide chains of alginate with AIEgen‐based surfactant molecules as the flexible contact points. The non‐covalent cross‐linking network provides sufficient energy‐dissipating slippage between polysaccharide chains, leading to Alg‐TPEA‐PEG with highly improved mechanical performances from the plastic strain stage. By successfully transferring the extraordinary mechanical performances of polysaccharide chains to macroscopic fibers, Alg‐TPEA‐PEG exhibits an outstanding breaking strength of 1.27 GPa, Young's modulus of 34.13 GPa, and toughness of 150.48 MJ m−3, which are comparable to those of dragline silk and outperforming other artificial materials. More importantly, both fluorescent and mechanical properties of Alg‐TPEA‐PEG can be well preserved under various harsh conditions, and the fluorescence and biocompatibility facilitate its biological and biomedical applications. This study affords a new biomimetic designing strategy for gaining super‐strong, super‐stiff, and super‐tough fluorescent biomaterials.

Fluorescent alginate fiber with super-strong and super-tough mechanical performances for biomedical applications

Emerging research attentions are focused on the development of fluorescent biomaterials for various biomedical applications, including fluorescence-guided surgery. However, it is still challenging to prepare biomolecules-based fluorescent fibers with both satisfactory biocompatibility and optimal mechanical properties. Here, we develop a fluorescent robust biofiber through using a tetraphenylethene-containing surfactant as the contact points between polysaccharide chains of alginate. This newly developed contact points not only strengthen the cross-linking network of polysaccharide chains, but also afford enough energy-dissipating slippage for polysaccharide chains. Consequently, the generated fluorescent fiber is endowed with highly improved mechanical performances from plastic strain stage. The experimental results indicate that the fluorescent fiber shows good mechanical properties of breaking strength of 1.10 GPa (12.09 cN/dtex), Young's modulus of 39.81 GPa and toughness of 137.26 MJ/m3, which are comparable to those of dragline silk and outperforming spider silk proteins and other artificial materials. More importantly, its satisfactory biosafety and wound healing-promoting ability as a fluorescent suture are solidly proved by both in vitro and in vivo assays, which opens an opportunity for its biological and biomedical applications. This study provides a novel strategy for the development of robust fluorescent biomaterials.

Glymphatic clearance is enhanced during sleep.

We here revisited the concept that glymphatic clearance is enhanced by sleep and anesthesia. Utilizing dynamic magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and fluorescent fiber photometry, we report brain glymphatic clearance is enhanced by both sleep and anesthesia, and sharply suppressed by wakefulness. Another key finding was that less tracer enters the brains of awake animals and that brain clearance across different brain states can only be compared after adjusting for the injected tracer dose.

Two-Dimensional Material-Based Fluorescent Optical Fiber for Early Detection of Partial Discharge

Two-Dimensional Material-Based Fluorescent Optical Fiber for Early Detection of Partial Discharge

Optical signals measurement of discharge plasma in air switch cabinet using a fluorescent optical fiber as the sensor

Air switch cabinets are widely employed in the power industry, there is, however, no reliable methods for detecting partial discharges (PDs). Because fiber optic-based sensors are easy to install and have anti-electromagnetic interference capabilities, they are well suited for PDs detection in switch cabinets with their many components and metal shell structure. In this work, corona discharge in an air switch cabinet was detected using fluorescent fiber, and the characteristics of PDs were analyzed. Furthermore, experimental investigations were conducted to explore the impact of gas pressure and fiber length on the PDs detection. The results exhibit a correlation between the aforementioned factors and the PDs’ total amplitude, maximum amplitude, number of pulses and detection limit of PD quantity. The results can provide references for the application of fluorescent optical fiber on the PD detection in air switch cabinet.

High Stability and Corrosion-Resistant Gas of Recyclable and Versatile Manganese-Doped Lead-Free Double Perovskite Crystals toward Novel Functional Fabric and Photoelectric Device.

Lead-free halide perovskites possess excellent photoelectric properties, making them widely used in the photoelectric fields. Herein, lead-free double perovskite crystals (PCs) doped with manganese (Cs2NaInCl6:Mn2+) are successfully prepared by the more energy-efficient crystallization method. The crystals emit bright orange-red light under the ultraviolet (UV) lamp, showing unique optical properties. They have the highest photoluminescence quantum yield of 42.91%. The white light-emitting diodes (LEDs) are fabricated using these perovskite crystals, which show a color rendering index of 92 and external quantum efficiency (EQE) as high as 16.3%. Furtherly, perovskite-modified fiber paper made of aramid chopped fibers (ACFs) and polyphenylene sulfide (PPS) exhibited fluorescent properties under different conditions. This paper combines fiber composite technology with PPS fiber filter bags, which are widely used in environmental protection, for the first time and demonstrates functional fiber filter bags with fluorescent characteristics. This filter bag provides an idea for the automatic detection of industrial filtration. Meanwhile, after being exposed to industrial waste gas for 60h, the filter bag can maintain superior fluorescence performance. In this study, lead-free double perovskites are synthesized using an efficient method for preparing high-performance LEDs and high-stability fluorescent fibers. Concurrently, the application of perovskites in environmental protection is expanded.

Manipulable multipurpose nanothermometers based on a fluorescent hybrid glass fiber microsphere cavity

Manipulable multipurpose nanothermometers based on a fluorescent hybrid glass fiber microsphere cavity

The Iridescent Painting Palette of Michelino da Besozzo: First Results of Non-Invasive Diagnostic Analyses

This study concerns the characterization of the color palette of Michelino da Besozzo, one of the leading painters and illuminators of the Late Gothic period in Northern Italy. The artist’s relationship with the color blue was investigated by considering the recipe for lapis lazuli given by the artist to Giovanni Alcherio in Venice in 1410 and found in the medieval treatise of Jean Lebegue. The paper highlights this important evidence for the study of painting technique in the first half of the 15th century with an analytical and technical study of two paintings: The Mystic Marriage of Saint Catherine (Siena, Pinacoteca Nazionale, inv. 171) and The Madonna of the Rose Garden (Verona, Museo di Castelvecchio, inv. 173-1B359). These two case studies were approached through analyses carried out with non-invasive and portable techniques such as Energy Dispersive X-ray Fluorescence (ED-XRF) spectroscopy and Fiber Optics Reflectance Spectroscopy (FORS). The results show a color palette based on ultramarine, azurite, verdigris or copper resinate; earths, cinnabar or vermillion; and lead white, yellow and red ochre and lac. These preliminary results made it possible to clarify certain aspects of the artist’s style and his painting technique and identify common elements between the two works of art.

Fluorescent modification and performance study of carbon quantum dots on twisted bamboo fiber bundles

ABSTRACT In recent years, carbon quantum dots (CQDs) have been employed in the functionalization research of fiber-based materials due to their distinctive physicochemical properties. We used citric acid and urea as precursors and combined with hydrothermal method to prepare green and non-toxic carbon quantum dots (NCQDs), which were loaded into four-color twisted bamboo fiber bundles and possessed photoluminescence effect by simple impregnation method. Based on the verification of the structure and fluorescence properties of NCQDs, the fluorescent twisted bamboo fiber tows were comparatively analyzed for their chemical composition, microscopic morphology, mechanical properties, color difference, and thermal stability. The results showed that the four groups of fluorescent twisted bamboo fiber tows emitted uniform and bright blue fluorescent effects under UV light irradiation, and increased the tensile strength by 19.77% ~ 39.27% and the sexual modulus by 66.11% ~ 88.78% compared with the original twisted bamboo fiber tows. The impregnated carbon quantum dot solution enhances the functionality of the fiber bundle while enriching the color expression. It is expected to be a potential application material in the fields of smart marking, fluorescent anti-counterfeiting, interior decoration, and home textile industry.

Influence of the average wavelength on the scale factor stability of interferometric fiber optic gyroscope

The introduction of closed-loop mechanisms has significantly enhanced the performance of interferometric fiber optic gyroscopes (IFOGs). However, the poor scale factor (SF) stability limits its further application due to the use of broadband light sources. This study first reviewed the impact of the average wavelength of a light source on SF stability in a closed-loop IFOG setup. A simulation model is developed according to modulation and demodulation principles, and the SF error is found to be proportional to the wavelength drift in a closed-loop IFOG. Additionally, employing a laser with a more stable average wavelength instead of a super fluorescent fiber source (SFS) for driving the IFOG enhanced the SF stability by an order of magnitude to 0.38 ppm in ambient-air experiments, which is one of the best SF performances achieved thus far. With the significant improvement in stability during the variable temperature tests, the IFOG measures rotation rates more accurately.

Wavelength Division Multiplexing in Visible Light Communications Using Fluorescent Fiber Antennas

Wavelength Division Multiplexing in Visible Light Communications Using Fluorescent Fiber Antennas

Highly sensitive ratiometric fluorescent fiber matrices for oxygen sensing with micrometer spatial resolution

AbstractOxygen (O2)-sensing matrices are promising tools for the live monitoring of extracellular O2 consumption levels in long-term cell cultures. In this study, ratiometric O2-sensing membranes were prepared by electrospinning, an easy, low-cost, scalable, and robust method for fabricating nanofibers. Poly(ε-caprolactone) and poly(dimethyl)siloxane polymers were blended with tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) dichloride, which was used as the O2-sensing probe, and rhodamine B isothiocyanate, which was used as the reference dye. The functionalized scaffolds were morphologically characterized by scanning electron microscopy, and their physicochemical profiles were obtained by Fourier transform infrared spectroscopy, thermogravimetric analysis, and water contact angle measurement. The sensing capabilities were investigated by confocal laser scanning microscopy, performing photobleaching, reversibility, and calibration curve studies toward different dissolved O2 (DO) concentrations. Electrospun sensing nanofibers showed a high response to changes in DO concentrations in the physiological-pathological range from 0.5% to 20% and good stability under ratiometric imaging. In addition, the sensing systems were highly biocompatible for cell growth promoting adhesiveness and growth of three cancer cell lines, namely metastatic melanoma cell line SK-MEL2, breast cancer cell line MCF-7, and pancreatic ductal adenocarcinoma cell line Panc-1, thus recreating a suitable biological environment in vitro. These O2-sensing biomaterials can potentially measure alterations in cell metabolism caused by changes in ambient O2 content during drug testing/validation and tissue regeneration processes. Graphic abstract

Breakthrough Boost of Stokes Fluorescence from Er3+ in Perovskites for Flexible Temperature Sensing

AbstractPerovskites with ultra‐low phonon energy have excellent radiation properties, while the population distribution of its luminescent initial state needs to be facilitated to further optimize the stokes fluorescence of Er3+ under high‐energy photons excitation. Herein, UV excitability of Er3+ is remodeled by building an energy transfer channel from Sb3+ to Er3+ in Cs2NaInCl6 (CNIC) microcrystal to realize the enhancement of stokes fluorescence of Er3+. Under UV excitation, the breakthrough boost of Er3+ is observed in Cs2NaInCl6:Sb3+‐Er3+ (CNIC:Sb‐Er), and the sensitization coefficient from Sb3+ to Er3+ in CNIC is derived to be as high as 112. Moreover, CNIC:Sb‐Er is embedded into functional fibers to enhance the crystal stability and the composite flexibility, which form fluorescence fibers with strong radiation transition probability. Finally, a high‐precision temperature sensing is achieved based on FIR (fluorescence intensity ratios) technology, and the maximum relative sensitivities of CNIC:Sb‐Er phosphors and CNIC:Sb‐Er/PAN fibers reach 1.13 and 1.10% K−1, respectively, indicating that CNIC:Sb‐Er and CNIC:Sb‐Er/PAN fibers have potential applications in optical temperature sensors.

Phosphine-Capped Effects Enable Full-Color Clusteroluminescence in Nonconjugated Polyesters.

Full-color luminophores have advanced applications in materials and engineering, but constructing color-tunable clusteroluminescence (CL) from nonconjugated polymers based on through-space interactions remains a huge challenge. Herein, we develop phosphine-capped nonconjugated polyesters exhibiting blue-to-red CL (400-700 nm) based on phosphine-initiated copolymerization of epoxides and cyclic anhydrides, especially P1-0.5TPP, which exhibits red CL (610 nm) with a high quantum yield of 32%. Experiments and theoretical calculations disclose that the phosphine-capped effect in polyesters brings about conformational changes and induces phosphine-ester clusters by through-space (n,π*) interactions. Moreover, CL colors and efficiencies can be easily tailored by types of phosphines, compositions and structures of polyesters, and concentration. Significantly, the role of polymer motions (group, segmental, and chain motions) on CL originating from microregions inside polyesters is revealed. Further, phosphine-capped nonconjugated polyesters are demonstrated to be nonconjugated dyes and fluorescent fibers and are also used for multicolor light-emitting diodes including white light. This work not only provides an engineering strategy based on the end-group effect to prepare full-color clusteroluminogens but also broadens the prospects for material applications.

Preparation of polychromatic AIZS QDs @ plant-based fluorescent fiber (AIZS@F) by one-step hydrothermal method

Preparation of polychromatic AIZS QDs @ plant-based fluorescent fiber (AIZS@F) by one-step hydrothermal method

Hybrid cross-linking for the synthesis of highly tough fluorescent alginate fibers

The limited mechanical performance and functional constraints of alginate fibers significantly impede their development in the context of professional research. To address the aforementioned issues, this study initially utilized polyethyleneimine (PEI) and citric acid to synthesize carbon quantum dots (CD) with surface amino functionalization. Subsequently, in a sodium alginate (SA) solution, CD and vinyl silicon-based nanoparticles (VSNP) were co-introduced. Utilizing the abundant hydroxyl and carboxyl groups in polysaccharides, stable interactions were achieved with CD and VSNP. Incorporating a dynamic hydrogen-bonded crosslinking network among CD, VSNP and SA, the establishment of a calcium alginate (CA) ionically crosslinked network is facilitated via calcium-sodium ion exchange. Additionally, the interwoven and interlocked structure between the aforementioned dual networks was established. Employing a wet spinning process, the synergistic multiple dynamic energy dissipation mechanisms significantly enhance the mechanical performance. Fluorescent alginate fibers (CA/VSNP/CD) were prepared. The tensile strength was 3.81 cN/dtex, and the elongation at break was 13.16%. Compared to pure CA fibers, there were respective increases of 95.38% and 82.02%. Simultaneously, the fibers exhibit excitation-dependent emission characteristics. This work lays the foundation for potential applications of fluorescent alginate fibers in environmental monitoring, chemical sensors, dynamic anti-counterfeiting, and biomedical fields.