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Highly Sensitive Optical Biosensing of Staphylococcus aureus with an Antibody/Metal-Organic Framework Bioconjugate
摘要： In this research, a new luminescent bioprobe was developed for the detection of S. aureus based on bio-conjugation of an amine functionalized metal-organic framework (NH2-MIL-53(Fe)) with an anti-S. aureus antibody (Ab). The formation of the desired bioprobe (Ab/NH2-MIL-53), in its liquid phase, has been verified with several spectroscopic and structural characterizations. The bioprobe was incubated with varying concentrations of S. aureus bacteria. The resulting antibody conjugated bioprobe (Ab/NH2-MIL-53) maintained a strong inverse correlation in which decreases in fluorescence intensity were accompanied by increase in bacterial count. Thus, the potential of the herein developed probe has been successfully demonstrated for the detection of S. aureus with a low limit of detection (85 CFU/mL) over a wide concentration range (40 × 102 - 4 × 108 CFU/mL). It was further found to be reliable with regard to inter-/intra- precision assays and long-term stability. The feasibility of the method was further supported through the detection of S. aureus spiked in environmental samples (e.g., river water and cream pastry).
关键词： bacteria,real sample analysis,S. aureus,fluorescent sensor,Metal-organic framework
更新于2025-09-19 17:15:36
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A cost-effective realization of multimode exciton-polaritons in single-crystalline microplates of a layered metal-organic framework
摘要： We report the observation of multimode exciton-polaritons in single-crystalline microplates of a two-dimensional (2D) layered Metal-Organic Framework (MOF), which can be synthesized through a facile solvothermal approach, thereby eliminating all fabrication complexities usually involved in the construction of polariton cavities. With a combination of experiments and theoretical modelling, we have found that the exciton-polaritons are formed at room temperature, as a result of a strong coupling between Fabry-Perot cavity modes formed inherently by two parallel surfaces of a microplate and Frenkel excitons provided by the 2D layers of dye molecular linkers in the MOF. Flexibility in rational selection of dye linkers for synthesizing such MOFs renders a large-scale, low-cost production of solid-state, micro- exciton-polaritonic devices operating in the visible and near infrared (NIR) range. Our work introduces the MOF as a new class of potential materials to explore polariton-related quantum phenomena in a cost-effective manner.
关键词： Strong Coupling,Exciton-Polaritons,Multimode Coupling,Metal-Organic Framework,Angle-Resolved Reflectivity,Rhodamine B
更新于2025-09-19 17:15:36
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Strain coupling and dynamic relaxation in multiferroic metal-organic framework [(CH3)2NH2][Mn(HCOO)3] with perovskite structure
摘要： Strain coupling with ferromagnetism and ferroelectricity plays an important role in the development of multiferroic metal-organic frameworks (MOFs) with strong magnetoelectric coupling, but the underlying mechanisms have not been well understood. Strain coupling and dynamic relaxation in multiferroic MOF with perovskite structure [(CH3)2NH2][Mn(HCOO)3] were investigated using X-ray diffraction (XRD), Raman spectroscopy, Infra-red (IR) spectroscopy, differential scanning calorimetry (DSC), magnetic measurements and dynamic mechanical analysis (DMA). DSC results showed peaks at 183 K and 190 K at the rate of 5 K/min during cooling and heating processes, respectively. Magnetic measurements showed magnetic transition at ~ 8.5 K at the heating rate of 2 K/min. Temperature and frequency dependences of elastic properties studied by DMA at frequencies of 0.5 Hz to 10 Hz between 140 K and 300 K at heating rate of 2 K/min indicated that the minimum in storage modulus and the maximum in loss modulus and loss factor occurred near 190 K. The peak height of loss modulus and loss factor decreased at higher frequency, and the peak temperature was independent of frequency, showing the features of first-order phase transition. Near 190 K, paraelectric to ferroelectric phase transition triggered by disorder–order transition of alkylammonium cations located in the framework cavities occurred accompanied by the structural phase transition from rhombohedral space group R c to monoclinic space group Cc. The elastic anomalies and large energy loss near 190 K were associated with the coupling of the local strain with the freezing of dimethylammonium cation and the freezing of twin walls.
关键词： Elastic modulus,Energy loss,Metal-organic framework (MOF),Phase transition,Dynamic mechanical analysis (DMA)
更新于2025-09-19 17:15:36
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Facile graft copolymer template synthesis of mesoporous polymeric metal-organic frameworks to produce mesoporous TiO2: Promising platforms for photovoltaic and photocatalytic applications
摘要： Mesoporous polymeric metal-organic frameworks (mesoporous polymeric MOFs) are prepared on fluorine-doped tin oxide (FTO) substrate using hydrophilic terephthalic acid as the ligands, titanium isopropoxide as polymeric MOF precursors, and amphiphilic graft copolymers (i.e., poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) as structure-directing agents. The hydrophilic POEM chains in amphiphilic graft copolymers interact with the hydrophilic ligands and polymeric MOF precursors. Following thermal treatment at 500 °C, mesoporous polymeric MOFs are transformed to mesoporous TiO2 with high specific surface area and crystallinity, suitable for photovoltaic and photocatalytic applications. Solid-state dye-sensitized solar cells (ssDSSCs) and dye-sensitized solar cells (DSSCs) fabricated with mesoporous TiO2 photoanodes have efficiencies of 7.45 and 8.43 % at 100 mW/cm2, which is much higher than that of ssDSSCs and DSSCs with photoanodes of conventional TiO2 (5.36 and 7.14 %), respectively. The enhanced efficiency is attributed to good interconnectivity, larger surface area, and high porosity of the mesoporous TiO2, which results in suppressed interfacial charge recombination loss, enhanced electron transport, increased dye loading, and facilitated penetration of the electrolytes. Mesoporous TiO2 shows excellent activity as a photocatalyst for the degradation of humic acid under UV light irradiation.
关键词： Photocatalyst,Dye-sensitized solar cell (DSSC),Metal-organic framework (MOF),Graft copolymer,Titanium dioxide (TiO2),Polymerized ionic liquid,Mesoporous
更新于2025-09-19 17:13:59
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3D printing of mixed matrix films based on metal-organic frameworks and thermoplastic polyamide 12 by selective laser sintering for water applications
摘要： The fabrication of metal-organic framework (MOF)-based macro-materials is considered as a promising strategy towards the practical applications of powdered MOF crystals. In this study, selective laser sintering (SLS), an advanced three-dimensional (3D) powder printing technique, has been employed to fabricate MOF-polymer mixed matrix films (MMFs) using thermoplastic polyamide 12 (PA12) powder as the matrix material and five types of MOFs including ZIF-67, NH2-MIL-101(Al), MOF-801, HKUST-1 and ZIF-8 crystals as the fillers. A three-layer HKUST-1-PA12 complex with a grid pattern is fabricated to demonstrate the printability of 3D MOF-polymer structure. Single-layer MMFs with grid patterns are printed using the five types of MOF fillers with different mass loadings to study their free-standing characteristic, thickness, specific surface area, hydrophilia, water permeate flux and mechanical stability. The methylene blue (MB) adsorption tests are conducted using the NH2-MIL-101(Al)-PA12 MMFs with different grid patterns to exemplify the applications of the MMFs for water purification. It is confirmed that the MOF components retain their high maximum adsorption capacity and the printed MMFs can be conveniently regenerated for cyclic utilization. This work provides an insight into the utilization of advanced 3D printing technology to manufacture macro MOF-polymer materials for practical applications.
关键词： water purification,metal-organic framework,3D printing,selective laser sintering,mixed matrix film
更新于2025-09-16 10:30:52
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Facile Synthesis of Uniform Metal Carbide Nanoparticles from MOFs by Laser Metallurgy
摘要： We report the fast and efficient conversion of metal-organic frameworks (MOFs) to phase pure transition metal carbide (TMC) nanoparticles with uniform size using laser as the energy source, consuming only 6-Watt power. Nanoparticles of HfC, ZrC, TiC, V8C7, α-MoC, Cr3C2 and FeCx with homogeneous sizes (varied between 6 and 20 nm) were successfully produced, among which HfC and ZrC nanoparticles were obtained, for the first time, with sizes less than 10 nm and in pure phase. This method was operated directly in air, in stark contrast to traditional furnace heating and laser spray methods, where protective atmosphere are required. The use of MOFs allowed us to precisely tune the composition of TMC nanoparticles by dialing in the right type and desirable amounts of organic linkers. FeCx nanoparticles doped with various percentages of nitrogen atoms were synthesized for Fischer-Tropsch reaction without any pretreatment or activation. Extremely high iron time of yield (FTY) values were observed, 415 μmol gFe -1 s-1 and 550 μmol gFe -1 s-1 (with addition of K), in a 40 h test without any decay in performance. High olefin to paraffin ratio was achieved for C2 to C11 products, where the ratio for C3 was higher than 10.
关键词： laser,nano,transition metal carbide,metal-organic framework,Fischer-Tropsch synthesis
更新于2025-09-12 10:27:22
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Ultrafast Melting of Metal–Organic Frameworks for Advanced Nanophotonics
摘要： The conversion of metal–organic frameworks (MOFs) into derivatives with a well-defined shape and composition is considered a reliable way to produce efficient catalysts and energy capacitors at the nanometer scale. Yet, approaches based on conventional melting of MOFs provide the derivatives such as amorphous carbon, metal oxides, or metallic nanoclusters with an appropriate morphology. Here ultrafast melting of MOFs is utilized by femtosecond laser pulses to produce a new generation of derivatives with complex morphology and enhanced nonlinear optical response. It is revealed that such a nonequilibrium process allows conversion of interpenetrated 3D MOFs comprising flexible ligands into well-organized spheres with a metal oxide dendrite core and amorphous organic shell. The ability to produce such derivatives with a complex morphology is directly dependent on the electronic structure, crystal density, ligand flexibility, and morphology of initial MOFs. An enhanced second harmonic generation and three-photon luminescence are also demonstrated due to the resonant interaction of 100–1000 nm spherical derivatives with light. The results obtained are in the favor of new approaches for melting special types of MOFs for nonlinear nanophotonics.
关键词： ultrafast melting,femtosecond laser,nanophotonics,metal–organic framework,derivatives
更新于2025-09-12 10:27:22
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Simultaneous laser-induced synthesis and micro-patterning of a metal organic framework
摘要： Micro-patterning of a metal organic framework (MOF) from a solution of precursors is achieved by local laser heating. Nano-sized MOFs are formed, followed by rapid assembly due to convective flows around a heat-induced micro-bubble. This laser-induced bottom-up technique is the first to suggest simultaneous synthesis and micro-patterning of MOFs, alleviating the need for pre-preparation and stabilization.
关键词： laser-induced synthesis,metal organic framework,Marangoni convection flows,micro-patterning,nano-MOFs
更新于2025-09-12 10:27:22
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The fabrication of Au/Pd plasmonic alloys on UiO-66-NH <sub/>2</sub> : an efficient visible light-induced photocatalyst towards the Suzuki Miyaura coupling reaction under ambient conditions
摘要： Visible light harvesting by heterogeneous photocatalysts and their applications in organic transformation reactions for the synthesis of target molecules are quite demanding science in the current scenario. In this regard, herein, a novel metal (Au/Pd)-functionalized metal organic framework (UiO-66-NH2) was synthesized to carry out the Suzuki–Miyaura coupling (SMC) reaction under visible light irradiation at ambient conditions. In order to justify the claim regarding the formation of alloys, crystallinity, morphology, particle size, proper separation of excitons, elemental content and their environment, various sensitive characterization techniques such as XRD, XPS, HRTEM, BET surface area and UV-vis analysis were employed. A mechanistic approach by means of experimental investigations revealed that the strong LSPR effect of Au facilitated the transfer of electrons to the Pd surface to make the surface negatively charged and suitable for the activation of aryl halides. The formed electropositive Au nanoparticles were converted to Au0 by accepting the photo-induced electrons from pristine UiO-66-NH2 and made available only holes at VB for the activation of phenylboronic acid. Among all the synthesized photocatalysts (1 : 2), Au/Pd@UiO-66-NH2 showed the highest activity (>99%) with TOF = 426 h?1 in an EtOH/H2O medium towards the SMC reaction, and the highest activity of this catalyst was supported by the electron gas model, LSPR effect (UV-vis) and active species separation (PL) analysis. The bimetallic noble nanoparticle-anchored UiO-66-NH2 not only expands the synthesis scope of C–C coupling by the SMC reaction under ambient conditions but will also inspire the further exploration of the activation of various reactants towards a wide range of organic transformation reactions.
关键词： visible light harvesting,Suzuki–Miyaura coupling,heterogeneous photocatalysts,LSPR effect,Au/Pd-functionalized metal organic framework
更新于2025-09-12 10:27:22
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Phase-junction design of MOF-derived TiO2 photoanodes sensitized with Quantum Dots for efficient hydrogen generation
摘要： Photoelectrochemical (PEC) water splitting is a promising and environmentally friendly pathway for exploiting renewable energy sources, to address the ever-growing demand for clean energy. Due to its excellent photostability and favorable band alignment, titanium dioxide (TiO2) is the one of the most common metal oxide for water splitting. However, the efficiency in TiO2-based PEC systems is limited by the high recombination of photo-generated electron/hole pairs and large intrinsic band gap (3.2 eV) which limit the absorption of the sunlight. Herein, we explore a simple metal organic framework (MOF)-derived synthesis to obtain a controlled mixed-phase (anatase and rutile) of TiO2 nanoparticles, which retain the MOF crystal morphology. Compared with commercial TiO2 films, the MOF-derived TiO2 film sensitized by core-shell CdSe@CdS QDs, showed an enhanced PEC device stability of +42.1% and PEC performance of +47.6%. The enhanced performance is due to the presence of the mixed rutile/anatase phases, that creates a favorable band energy alignment for the separation of the photogenerated charges. The proposed MOF-derived TiO2 is an efficient strategy to improve the efficiency of the TiO2-QDs heterojunction based PEC system for hydrogen generation.
关键词： Metal organic framework,Mixed-phase TiO2,Photoelectrochemical water splitting,Quantum dots,Hydrogen generation
更新于2025-09-11 14:15:04