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A novel optical fiber glucose biosensor based on carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film
摘要： A novel optical fiber glucose biosensor based on fluorescent carbon quantum dots (CQDs)-glucose oxidase (GOD)/cellulose acetate (CA) complex sensitive film was fabricated, in which the dip-coating method was adopted to immobilize the CQDs-GOD/CA complex sensitive film onto the end face of the optical fiber. The surface morphology, microstructure and optical performances of the sensitive film were characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Zeiss Axiovert 25 inverted microscope, Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectrophotometer and fluorescence spectrophotometer, respectively. The developed fiber-optic biosensor exhibits high sensitivity and repeatability for continuous online detection of low concentration glucose, allowing visualization of real-time glucose fluctuations over a period of time. The change ratios in fluorescence intensity of the biosensor are linear with glucose concentration in various ranges including micromole and nanomole levels, and the relationship between relative fluorescence intensity ratio and glucose concentration complies well with the modified Stern-Volmer equation in the range of 10-200 μmol/L with the detection limit of 6.43 μM, and in the range of 10-100 nmol/L with the detection limit of 25.79 nM, respectively.
关键词： Optical fiber,Carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film,Glucose sensing,Fluorescence quenching
更新于2025-09-16 10:30:52
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Organosoluble Starch-Cellulose Binary Polymer Blend as a Quasi-Solid Electrolyte in a Dye-Sensitized Solar Cell
摘要： This work is a pioneer attempt to fabricate quasi-solid dye-sensitized solar cell (QSDDSC) based on organosoluble starch derivative. Rheological characterizations of the PhSt-HEC blend based gels exhibited viscoelastic properties favorable for electrolyte fabrication. From amplitude sweep and tack test analyses, it was evident that the inclusion of LiI improved the rigidity and tack property of the gels. On the other hand, the opposite was true for TPAI based gels, which resulted in less rigid and tacky electrolytes. The crystallinity of the gels was found to decline with increasing amount of salt in both systems. The highest photoconversion e?ciency of 3.94% was recorded upon addition of 12.5 wt % TPAI and this value is one of the highest DSSC performance recorded for starch based electrolytes. From electrochemical impedance spectroscopy (EIS), it is deduced that the steric hindrance imposed by bulky cations aids in hindering recombination between photoanode and electrolyte.
关键词： dye-sensitized solar cell,phthaloyl starch,rheology,hydroxyethyl cellulose,quasi-solid electrolyte
更新于2025-09-16 10:30:52
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Organosoluble starch derivative as quasi-solid electrolytes in DSSC: Unravelling the synergy between electrolyte rheology and photovoltaic properties
摘要： A novel blend of organosoluble phthaloyl starch (PhSt) and hydroxyethyl cellulose (HEC) was used as the polymer host to fabricate polymer gel electrolytes. Rheological analyses, such as amplitude sweep studies and tack tests, indicate that gels with good rigidity, strength and adhesiveness were attained upon inclusion of 20 wt % of HEC onwards. However, beyond 60 wt% of HEC, the mechanical properties and ionic conductivity of the gels were considerably compromised. Gels comprising 20–60 wt% of HEC were then fabricated into quasi-solid dye-sensitised solar cells (QSDSSC) with the addition of tetrapropylammonium iodide/iodine. The highest efficiency of 3.02% was recorded with gels comprising 70 wt% of PhSt and 30 wt% of HEC, which to the best of our knowledge is the highest ever efficiency in literature for starch-based electrolytes. Electrochemical impedance spectroscopy (EIS) of the QSDSSC revealed that the adhesive property of the gels plays a crucial role in charge transfer processes at the electrode/electrolyte interfaces.
关键词： Rheology,Hydroxyethyl cellulose,Dye-sensitised solar cell,Quasi-solid electrolyte,Phthaloyl starch
更新于2025-09-16 10:30:52
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A Green Slab Waveguide for Plasmonic Sensors Based on Bacterial Cellulose
摘要： We use as optical waveguide a green composite, based on bacterial cellulose (BC). More specifically, we have sputtered a thin gold film on this innovative slab waveguide for obtaining a Localized Surface Plasmon Resonance (LSPR) sensor. Experimental results confirm the possibility of using the BC based composite as an environmental friendly optical sensor platform with plasmonic capabilities, which could be exploited for realizing disposable biosensors. The new optical sensor has been used by combining it with optical fibers. The fibers connect the green disposable optical sensor with a light source and with a spectrometer. The device has been tested by measuring the refractive index of different water-glycerin solutions.
关键词： refractive index measurement,sustainable development,localized surface plasmon resonance,bacterial cellulose,optical sensors
更新于2025-09-12 10:27:22
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Ionically Modified Cellulose Nanocrystal Self-Assembled Films with a Mesoporous Twisted Superstructure: Polarizability and Application in Ion-Gated Transistors
摘要： Mesoporous structures made of cellulose nanocrystals (CNCs) and their self-assembly into films is of great interest not only due to their abundancy and sustainability but also due to their ease of chemical modification and nanoscale bio mimicry capabilities. However, their implementation in (opto)electronic devices requires further understanding on how these self-assembled twisted mesoporous superstructures respond to electrical stimulus. In this regard, this work focusses in the infiltration with three distinct alkali ions (Li+, Na+ and K+) to yield films with improved electrochemical response when compared to pristine ones, while preserving their photonic character. Electrochemical characterization shows capacitances of up to 2.5 μF cm-2 allowing for their integration as solid-state gate electrolytes in amorphous indium-gallium-zinc-oxide transistors, resulting in low operating voltages (< 2 V), On/Off ratios of up to 6 orders of magnitude and high saturation mobilities >10 cm2 V-1 s-1. Devices fabricated on Na+ and K+ infiltrated CNC films present the best characteristics, indicating pure capacitive charging of the semiconductor. The insights presented here contribute to applications in solid-state ionics in mesoporous structures or the combination of optically active electrolytes capable of providing unique functionalities in ion-gated transistors and circuitry.
关键词： Self-assembly,Mesoporous Structures,Cellulose Nanocrystals,Ion Gated Transistors,Photonics
更新于2025-09-12 10:27:22
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Plasmonic Metamaterial Gels with Spatially Patterned Orientational Order via 3D Printing
摘要： Optical properties can be programmed on mesoscopic scales by patterning host materials while ordering their nanoparticle inclusions. While liquid crystals are often used to define the ordering of nanoparticles dispersed within them, this approach is typically limited to liquid crystals confined in classic geometries. In this work, the orientational order that liquid crystalline colloidal hosts impose on anisotropic nanoparticle inclusions is combined with an additive manufacturing method that enables engineered, macroscopic three-dimensional (3D) patterns of co-aligned gold nanorods and cellulose nanocrystals. These gels exhibit polarization-dependent plasmonic properties that emerge from the unique interaction between the host medium’s anisotropic optical properties defined by orientationally ordered cellulose nanocrystals, from the liquid crystal’s gold nanorod inclusions, and from the complexity of spatial patterns accessed with 3D printing. The gels’ optical properties that are defined by the interplay of these effects are tuned by controlling the gels’ order, which is tuned by adjusting the gels’ cellulose nanocrystal concentrations. Lithe optical responsiveness of these composite gels to polarized radiation may enable unique technological applications like polarization-sensitive optical elements.
关键词： liquid crystals,optical properties,nanoparticles,plasmonic properties,cellulose nanocrystals,gold nanorods,3D printing
更新于2025-09-12 10:27:22
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Spectroscopic characterization at THz frequencies of glucose-based biomaterials: paramylon, paramylon-ester and cellulose
摘要： The terahertz (THz) spectroscopy of paramylon (β-1,3-glucan) and paramylon-ester extracted from microalgae called as Euglena have been studied by Fourier Transform Infrared Spectrometer (FT-IR) in a frequency range from 0.3 to 9 THz. The absorption spectra of paramylon were analyzed by comparing them with cellulose that has a similar long-chain -(C6H10O5)n-structure with paramylon. The differences in absorption features between paramylon and cellulose may be caused by their different chain structures. The broad absorption spectra of paramylon-ester can be attributed to some sort of disorder of long-chain molecular vibration modes due to the substitution of propionyl chloride and long-chain acid chloride by esterification.
关键词： microalgae,Euglena,paramylon-ester,paramylon,cellulose,terahertz spectroscopy,Fourier Transform Infrared Spectrometer
更新于2025-09-11 14:15:04
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Cellulose-Based Microparticles for Magnetically Controlled Optical Modulation and Sensing
摘要： Responsive materials with birefringent optical properties have been exploited for the manipulation of light in several modern electronic devices. While electrical fields are often utilized to achieve optical modulation, magnetic stimuli may offer an enticing complementary approach for controlling and manipulating light remotely. Here, the synthesis and characterization of magnetically responsive birefringent microparticles with unusual magneto-optical properties are reported. These functional microparticles are prepared via a microfluidic emulsification process, in which water-based droplets are generated in a flow-focusing device and stretched into anisotropic shapes before conversion into particles via photopolymerization. Birefringence properties are achieved by aligning cellulose nanocrystals within the microparticles during droplet stretching, whereas magnetic responsiveness results from the addition of superparamagnetic nanoparticles to the initial droplet template. When suspended in a fluid, the microparticles can be controllably manipulated via an external magnetic field to result in unique magneto-optical coupling effects. Using a remotely actuated magnetic field coupled to a polarized optical microscope, these microparticles can be employed to convert magnetic into optical signals or to estimate the viscosity of the suspending fluid through magnetically driven microrheology.
关键词： magneto-optical properties,polarized light,cellulose nanocrystals,microfluidics,microparticles
更新于2025-09-11 14:15:04
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Modification of cellulose fibers with inorganic luminescent nanoparticles based on lanthanide(III) ions
摘要： This article presents synthesis and properties of the fibers modified with luminescent, inorganic nanoparticles doped with lanthanide(III) ions, i.e. LaF3:Ce3+, Gd3+, Eu3+, CeF3:Tb3+ and CePO4:Tb3+. The fibers with luminescent properties were prepared via so called Lyocell process. This method involves dissolving cellulose in aqueous solution of N-methylmorpholine-N-oxide (NMMO) and a subsequent spinning of the fibers, using a dry-wet method. Thanks to the successful incorporation of the modifier nanoparticles (NPs) into the cellulose matrices, the fibers exhibited bright, multicolor emission upon UV irradiation and good mechanical properties, which allowed further textile processing. This type of fibers, as well as the as-prepared textiles/fabric can be used as an anti-counterfeiting agent for clothes and documents protection.
关键词： Lanthanide(III) ions,Luminescence,Multifunctional cellulose fibers
更新于2025-09-11 14:15:04
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Infrared Spectra for Alfa Fibers Treated with Thymol
摘要： In this work, we attempt to analyze the hydrogen bond network of cellulose by comparing the 2nd derivative infrared spectra of alfa fiber treated with different concentrations of thymol. It was proved, from this study, that the 2nd derivative infrared spectrum is a useful method for identifying the least changes incurred in the cellulosic supramolecular structure. It can be considered as an effective method to gain further insight on OH bond system of cellulosic materials and to clarify some grey areas in terms of infrared band assignment. The careful analysis of 2nd derivative infrared spectra of untreated and thymol treated alfa fibers revealed an increase in band intensity related to both intermolecular and intramolecular hydrogen bonds and a decrease in bands related to free hydroxyl groups.
关键词： Alfa fiber,FTIR spectrum,Cellulose,Hydrogen bonds,Thymol
更新于2025-09-10 09:29:36