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In Situ Enzyme Immobilization with Oxygen‐Sensitive Luminescent Metal–Organic Frameworks to Realize “All‐in‐One” Multifunctions
摘要： Metal-organic frameworks (MOFs) for enzyme immobilization have already shown superior tunable and designable characteristics, however, their devisable responsive properties have rarely been exploited. Herein, we integrated a responsive MOF into MOF-enzyme composite to propose an “all-in-one” multifunctional composite with catalytic and luminescence functions implemented within a single particle. As a proof-of-concept, glucose oxidase (GOx) was in situ encapsulated within an oxygen (O2)-sensitive, noble-metal-free luminescent Cu(I) triazolate framework (MAF-2), namely GOx@MAF-2. Owing to the rigid scaffold of MAF-2 and the confinement effect, the GOx@MAF-2 composite showed significantly improved stability (shelf life to 60 days and heat-resistance up to 80 oC) with good selectivity and recyclability. More importantly, the integration of the O2-sensitivity of MAF-2 allowed the GOx@MAF-2 composite rapidly and reversibly response toward dissolved O2, which realized direct and ratiometric sensing of glucose without the needs of chromogenic substrates, cascade enzymatic reactions or electrode system. A high sensitivity with a detection limit of 1.4 μM glucose was achieved, and the glucose in human sera was accurately determined. The strategy opens a new application of MOFs and can be facilely extended to various MOF-enzyme composites due to the multifunctionality of MOFs.
关键词： enzyme immobilization,metal-organic frameworks,all-in-one multifunctions,glucose detection,fluorometric sensor
更新于2025-11-21 11:08:12
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Preparation and immobilization of zinc sulfide (ZnS) nanoparticles on polyvinylidene fluoride pellets for photocatalytic degradation of methylene blue in wastewater
摘要： ZnS nanoparticles with 90 nm diameter were synthesized by low-temperature method and immobilized onto the surface of polyvinylidene fluoride (PVDF) pellets prepared by phase inversion method. Results by FTIR and X-ray photoelectron spectroscopy revealed that the ZnS nanoparticles were immobilized tightly on the PVDF surface without their release and losing photocatalytic activity. The UV-absorption spectra showed that the PVDF matrix had no adverse effect on the optical properties of ZnS nanoparticles. Due to large size (5 mm) and excellent mechanical stability, the PVDF-ZnS pellets could be easily dispersed in the photocatalytic reactor treating methylene blue solution. The removal efficiency of the methylene blue with the PVDF-ZnS pellets was higher (more than 95%) than that observed by the control PVDF pellets or ZnS nanoparticles tested. No change in the removal efficiency was observed as the PVDF-ZnS pellets were reused by performing photocatalytic tests at the same experimental conditions repeatedly.
关键词： Reusability,Polymer carrier,Zinc sulfide,Immobilization,Phase inversion,Photocatalytic degradation
更新于2025-11-14 15:14:40
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Synthesis of immobilized cerium doped ZnO nanoparticles through the mild hydrothermal approach and their application in the photodegradation of synthetic wastewater
摘要： The difficulty associated with accessing water resources, wastewater treatment and recycling are crucial subjects of research. In this regards the present research focuses on the synthesis, characterization, and photodegradation of synthetic wastewater by immobilized cerium doped ZnO nanoparticles. This was an experimental study at laboratory scale. The nanoparticles were synthesized through the mild hydrothermal technique and characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS), and Photoluminance analyses (PL). In addition, a reactor was designed and constructed for the photodegradation of the synthetic beverage effluent at laboratory scale. The fabricated nanoparticles were fixed on sand-blast glasses. The experiments were conducted by examining the parameters of doping percentage, pH, nanoparticle density, initial density of the wastewater sample, as well as exposure time to ultraviolet light and sunlight illumination. The doping molar percentage of cerium oxide in the photodegradation of the synthetic wastewater was shown to be effective, and the optimal percentage was observed at 1%. The results showed higher efficiency under the visible light illumination. Increasing the concentration of the effluent from 500 to 3000 mg/L resulted in the reduction of efficiency from 65.14 to 21.9 % under ultraviolet light and from 42.13 to 10.12% under visible light illumination. It was also found that increasing the exposure time would increase the efficiency of the wastewater photodegradation. The immobilized cerium doped zinc oxide nanoparticles showed excellent crystallinity and were well-dispersed.
关键词： Nanocatalysts,doping,immobilization,industrial wastewater,sunlight.
更新于2025-09-23 15:23:52
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Fabrication of new metal-free materials for the hydrogen evolution reaction on base of the acridine derivatives immobilized on carbon materials
摘要： The process of adsorption on carbon material (Vulcan XC-72 (VU)) of organic heterocyclic compounds: acridine (I) and its derivatives 9-phenylacridine (II) and N-methyl-9-phenylacridium iodide (III) was studied in detail. Quantitative data on physical adsorption were obtained for all compounds. Based on the adsorption isotherms of Langmuir, the adsorption equilibrium constants K, the parameter A∞ and ΔG0 ad were calculated. It has been shown that the adsorption of compounds I and II is a structurally dependent process that depends on the nature and size of the functional substituents in the molecule, and the adsorption of compound III has a complex mechanism and partially proceeds through the stabilization stage by the functional groups present on the surface (-COOH, -COH, -OH). With the use of quantum chemical calculations, it has been established that the process of adsorption of compounds on the surface of a carbon materials having sections with a graphite-like structure is thermodynamically unprofitable because of the high difference in the energies of the adsorbent's boundary orbitals and the substrate. Using the cyclic voltammetry method, the electrochemical properties of organic compounds immobilized on the surface of a carbon material were studied.
关键词： Electocatalysis,Acridine derivatives,Immobilization,Adsorption,Carbon materials,Hydrogen evolution reaction
更新于2025-09-23 15:22:29
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Biosensor for point-of-care analysis of immunoglobulins in urine by metal enhanced fluorescence from gold nanoparticles
摘要： Biosensors are easy-to-use and cost-effective devices that are emerging as an attracting tool not only in settling diagnosis or in disease monitoring, but also in mass screening tests, a timely topic that impacts on daily life of the whole society. Nanotechnologies lend themselves to the development of highly sensitive device whose realization has become a very interdisciplinary topic. Relying on the enhancement of the fluorescence signal detected at the surface of patterned gold nanoparticles, we report the behavior of an analytical device in detecting immunoglobulins in real urine samples that shows a limit of detection of approximately 8 μg/L and a linear range of 10-100 μg/L well below the detection limit of nephelometric method, which is the reference method for this analysis. These performances have been reached thanks to an effective surface functionalization technique and can be improved even more if superhydrophobic features of the substrate we produce will be exploited. Since the analyte recognition is realized by antibodies the specificity is very high and, in fact, no interference has been detected by other compounds also present in the real urine samples. The device has been assessed on serum samples by comparing IgG concentrations values obtained by the biosensor with those provided by a nephelometer. In this step we found that our approach allows the analysis of the whole blood without any pretreatment; moreover, it is inherently extendable to the analysis of most biochemical markers in biological fluids.
关键词： antibody,point-of-care device,nanostructured gold surface,photochemical immobilization technique,gold nanoparticles,metal enhanced fluorescence,biosensors
更新于2025-09-23 15:22:29
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Enzyme immobilization in completely packaged freestanding SU-8 microfluidic channel by electro click chemistry for compact thermal biosensor
摘要： Enzyme immobilization method in packaged freestanding microfluidic channel is developed for biomolecule assembly of biosensor in this research. A new micro fluidic fabrication method is proposed to fabricate freestanding fluidic structure by MEMS technology. The SU-8 polymer channel is treated by plasma treatment to change hydrophobic surface to hydrophilic property which can automatically drive the liquid into the channel by capillary force. The electro click chemistry method is carried out in hydrophilic SU-8 micro channel by capillary effect. The results show that enzyme immobilization can be immobilized by electro click chemistry in completely packaged freestanding channel. The proposed enzyme immobilization method in micro channel is capable of minimizing biosensor device for healthcare application.
关键词： Capillary effect,SU-8 polymer,Electro click chemistry,Enzyme immobilization,Microfluidic
更新于2025-09-23 15:22:29
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Visible Light TiO <sub/>2</sub> Photocatalyst Composite Based on Carbon Microfiber Derived from Human Hair
摘要： The present work reports titanium dioxide (TiO2) photocatalyst composite based on human hair that can operate efficiently under visible light. The human hair melanin structure contains active sites, which can be described as a carbon compound derived from a Quinone where one of two oxygen atoms is bonded to a hydrogen radical and that can be reversibly photogenerated under visible or ultraviolet irradiation. The human hair-derived microfibers (HHDMs) were created by the pyrolyzing hair at 850 °C, resulting in a rod-like hollow structure. TiO2 was immobilized on the pyrolyzed hair by a simple self-template method. The resulting composite was calcined at five different temperatures (150 to 350 °C). The HHDM and HHDM-TiO2 morphologies and the chemical compositions were characterized using scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). The HHDM-TiO2 photocatalytic efficiency in degrading methylene blue was investigated and compared to that of a conventional TiO2 catalyst (P25). HHDM-TiO2 was more effective for methylene blue degradation under visible light than the conventional P25 catalyst suspension due to the unique photosensitivity and porous structure of the composite. The catalyst calcined at 300 °C showed the best performance, which was 71% higher than that of the P25 catalyst.
关键词： Semiconductors,Immobilization,Titanium Dioxide,Waste prevention,Photocatalysis
更新于2025-09-23 15:21:21
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A reaction-and-assembly approach using monoamine zinc porphyrin for highly stable large-area perovskite solar cells
摘要： Inhibiting the irreversible escape of organic cations and iodide species in perovskite films is crucial for the fabrication of efficient and stable perovskite solar cells (PSCs). Here, we develop a reaction-and-assembly approach using monoamine zinc porphyrin (ZnP) to modify methylammonium (MA+) lead iodide perovskite film. The amine group in ZnP reacts with MA+ and I? ions to yield monoammonium zinc porphyrin (ZnP-H+I?). The resultant films show no escape of iodide when immersed in ether solutions. Measurements from space-charge limited currents and transient photoluminescence indicate the modified films have reduced density of defects. These results suggest the formed ZnP-H+I? is bound on the surface and grain boundary of perovskite film to retard migrations of ions. DFT calculations also show that the energy alignment between ZnP-H+ and perovskite facilitates the electron transfer and reduces charge recombination at the perovskite grains. Furthermore, post-treating the ZnP-doped film with ZnP again results in the formation of a one dimension zig-zag coordination polymer on the surface of the perovskite film. The single crystal structure of ZnP shows the polymer layer is formed through the coordination interaction between the Zn(II) metal center and a neighboring monoamine. The polymer facilitates the interfacial charge transfer, and reduces the escape of organic cations and iodide species in perovskite films, thereby keeping the excellent cell performance (20.0%) and further realizing the ion encapsulation. Finally, the modified PSCs retain over 90% of its original efficiency over 2,000 h at 85 °C or AM 1.5 G continuous illumination, or over 6,000 h in 45% humidity without encapsulation. This work affords a new strategy to achieve the efficient ions immobilization and encapsulation by in situ reaction and coordination assembly of mono-amine zinc porphyrin.
关键词： monoamine porphyrin,perovskite solar cells,ions immobilization,reaction-and-assembly
更新于2025-09-23 15:19:57
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[Methods in Molecular Biology] Autoantibodies Volume 1901 (Methods and Protocols) || Determination of CRP Autoantibodies by SPR Immunoassay
摘要： Biosensors based on the principle of surface plasmon resonance (SPR) are surface-sensitive optical devices used for monitoring biomolecular interactions at the sensor surface in real time without any labeling. It is used in a wide variety of areas including proteomics, clinical diagnosis, environmental monitoring, drug discovery, and food analysis. C-reactive protein (CRP) is a marker of in?ammation, which undergoes conformation changes in local lesions, leading to the formation of mCRP. Autoantibodies against mCRP are frequently detected in systemic lupus erythematosus (SLE) and associated with disease activity and prognosis. An SPR immunoassay for CRP autoantibodies at complement factor H–CRP interface is described in this chapter.
关键词： Surface plasmon resonance,CRP,Immobilization,Complement factor H,CRP autoantibody
更新于2025-09-23 15:19:57
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Small-incision lenticule extraction in a patient with high astigmatism and nystagmus
摘要： Small-incision lenticule extraction (SMILE) was performed in a patient with high astigmatism and nystagmus. The patient presented for a refractive surgery evaluation with a manifest refraction of -0.50 -6.00 × 137 (20/40-1) in the right eye and -2.25 -2.25 × 30 (20/40-1) in the left eye. The patient was deemed suitable for corneal laser refractive surgery. Consideration was given to SMILE, laser in situ keratomileusis, and photorefractive keratectomy. It was decided SMILE was the best option given that the refractive portion of the procedure is performed while the cornea is immobilized by suction. The treatment was uneventful, and the final manifest refraction was +0.25 -0.25 × 130 (20/40) in the right eye and +0.25 diopter sphere (20/40) in the left eye. Topography was normal, showing a well-centered treatment zone. This case highlights an additional use for SMILE, given its ability to immobilize the cornea during treatment.
关键词： astigmatism,SMILE,refractive surgery,cornea immobilization,nystagmus
更新于2025-09-19 17:15:36