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Confinement of Singlet Oxygen Generated from Ruthenium Complex-Based Oxygen Sensor in the Pores of Mesoporous Silica Nanoparticles
摘要： We synthesized mesoporous silica nanoparticles bearing ruthenium complexes in their pores (MSN-Ru) and characterized their photochemical properties. The ruthenium complexes that were immobilized in the pores showed oxygen-dependent phosphorescence, similar to the complexes that were not tethered to nanoparticles. Cellular imaging and in vivo experiments revealed that hypoxic cells and tissues could be visualized by monitoring the phosphorescence of MSN-Ru. Our most important finding was that the toxic effect of singlet oxygen (1O2), which was generated by excitation of the complexes, was effectively suppressed by the deactivation before leaking out from the pores. In addition, we observed a negligible toxic effect of the ruthenium complexes themselves due to the blockage of their direct interaction with intracellular biomolecules. Thus, MSN-Ru is a promising molecular probe of oxygen levels in living cells and tissues.
关键词： ruthenium complexes,singlet oxygen,in vivo experiments,cellular imaging,oxygen sensor,mesoporous silica nanoparticles
更新于2025-09-04 15:30:14
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Ammonium Persulfate and Potassium Oleate Containing Silica Dispersions for Chemical Mechanical Polishing for Cobalt Interconnect Applications
摘要： We investigated the suitability of ammonium persulfate (APS) and potassium oleate (PO) containing silica dispersions for polishing Co interconnects based on removal and dissolution rates, corrosion, post-polish surface quality, and post-polish particle contamination. A slurry consisting of 3 wt% silica, 1 wt% APS and 0.2 mM PO produced a removal rate of ～465 nm/min at pH 9, along with removal rate selectivity of >100:1 between Co and TiN. The same composition but without abrasives reduced the (cid:2)Ecorr between Co and TiN to ～ 7 mV and Igc to ～0.04 μAcm?2, indicating minimal galvanic corrosion. Addition of PO led to no measurable dissolution of the Co ?lms. Surface analysis showed very good post-polish surface quality and minimal contamination with silica particles. These and results obtained with similar H2O2 containing slurries suggest that the APS and PO-based silica slurry is more suitable for the Co bulk CMP process. The roles of persulfates ions, pH, and PO on the removal process and passivation behavior of Co are discussed and a removal mechanism is proposed.
关键词： potassium oleate,Ammonium persulfate,cobalt interconnect applications,chemical mechanical polishing,silica dispersions
更新于2025-09-04 15:30:14
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Fe3O4/SiO2 Core Shell Nanostructures: Preparation and Characterization
摘要： Silica coated iron oxide nanoparticles with controlled silica shell thickness were prepared by a modified St?ber method. Modification of the St?ber method consisted of changing the synthesis conditions to control the thickness of the SiO2 shell. The core-shell nanoparticles were characterized by means of X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy and vibrational sample magnetometry. It was found that the shell formed after 8 hours of stirring. An increase of the tetraethoxysilane-magnetite mass ratio from 12.5 to 25.1 led to an increase of the shell thickness, whereas further increase in the tetraethoxysilane-magnetite mass ratio (from 25.1 to 37.6) led to decrease shell thickness. The core size has only insignificant influence on the shell thickness. Magnetic properties of composite particles correlate well with properties of pure magnetite nanoparticles considering dilution of magnetic particles by silica. Obtained results can be used for fabrication of silica shell with controlled thickness on the surface of different sized magnetite nanoparticles.
关键词： FTIR,iron oxide,surface functionalization,silica coated,nanoparticles
更新于2025-09-04 15:30:14
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Fabrication of Immunosensor Based on Au-silica Nanocomposite for Neuron-specific Enolase Detection
摘要： Neuron-specific enolase (NSE), a type of neuroendocrine molecule, is a putative serum marker for small-cell lung carcinoma. This work addressed the fabrication of a signal-enhanced, label-free, electrochemical immunosensor based on Au nanoparticle/mesoporous silica nanoparticles (Au-MSNs) for NSE determination. Because of the large number of active sites provided by the Au-SiO2 sensor, the modified immunosensor has a significantly enhanced sensitivity. Furthermore, during quantitative NSE detection, the sensor has a desirable linear relationship with the concentration (0.1-2000 ng/mL) and a detection limit of 0.05 ng/mL.
关键词： Neuron-specific enolase (NSE),Label-free,Electrochemical immunosensors,Silica immunosensor,Signal-enhanced
更新于2025-09-04 15:30:14
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Silica bead-based microfluidic device with integrated photodiodes for the rapid capture and detection of rolling circle amplification products in the femtomolar range
摘要： The rapid and sensitive detection of specific nucleic acid sequences at the point-of-care (PoC) is becoming increasingly in demand for a variety of emergent biomedical applications ranging from infectious disease diagnostics to the screening of antimicrobial resistance. To meet such demand, considerable efforts have been invested towards the development of portable and integrated analytical devices combining microfluidics with miniaturized signal transducers. Here, we demonstrate the combination of rolling circle amplification (RCA)-based nucleic acid amplification with an on-chip size-selective trapping of amplicons on silica beads (~8 nL capture chamber) coupled with a thin-film photodiode (200 × 200 μm area) fluorescence readout. Parameters such as the flow rate of the amplicon solution and trapping time were optimized as well as the photodiode measurement settings, providing minimum detection limits below 0.5 fM of targeted nucleic acids and requiring only 5 μL of pre-amplified sample. Finally, we evaluated the analytical performance of our approach by benchmarking it against a commercial instrument for RCA product (RCP) quantification and further investigated the effect of the number of RCA cycles and elongation times (ranging from 10 to 120 minutes). Moreover, we provide a demonstration of the application for diagnostic purposes by detecting RNA from influenza and Ebola viruses, thus highlighting its suitability for integrated PoC systems.
关键词： Microfluidics,Infectious disease diagnostics,Silica microbeads,Photodiodes,Rolling circle amplification
更新于2025-09-04 15:30:14
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Ionic Current Rectification by Laminated Bipolar Silica Isoporous Membrane
摘要： Ionic current rectification (ICR) is one of interesting characteristics displayed by nanochannels with asymmetric ge-ometry, ionic concentration or charge distribution, which has been utilized for the development of chemical sensors and biosensors. Herein we report the ICR phenomenon observed with ultrathin silica isoporous membrane (SIM), which was prepared by laminat-ing two layers of SIM with opposite charges and different pore dimeters, designated as bipolar SIM (bp-SIM). The negatively charged layer, called as n-SIM, was 86-nm-thick and consisted of channels with a diameter of 2–3 nm. The positively charged layer with a thickness of 59 nm, termed as p-SIM, was comprised of channels of 4.5–5.5 nm in diameter. They were primarily grown on the solid surface using the St?ber-solution and biphasic-stratification growth approaches, respectively, and then exfoliated to obtain perforated structures by the polymer-protected chemical etching and transfer method. The negative charges of n-SIM and positive ones of p-SIM were generated by the deprotonation of pristine surface silanol and post-modified ammonium groups, respectively. Neither n-SIM nor p-SIM alone displays the ICR characteristic, because of their symmetric structure and uniform charge distribu-tion. When laminating two of them, an apparent ICR characteristic was observed for the bp-SIM with a typical diode-like current-voltage response. This behavior was rationalized to arise from the asymmetric charge distribution on two layers by finite element simulations. Considering the facile preparation and diverse surface functionalities, as well as its uniform and highly porous structure, the bp-SIM provides an attractive platform for designing ICR-based sensors.
关键词： bipolar SIM,nanochannels,asymmetric charge distribution,Ionic current rectification,silica isoporous membrane
更新于2025-09-04 15:30:14
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Highly Stable Luminous “Snakes” from CsPbX3 Perovskite Nanocrystals Anchored on Amine-Coated Silica Nanowires
摘要： CsPbX3 (X=Cl, Br and I) perovskite nanocrystals (NCs) are known for their exceptional optoelectronic properties, yet the material’s instability towards polar solvents, heat or UV irradiation greatly limits its further applications. Herein, an efficient in-situ growing strategy has been developed to give highly stable perovskite NC composites (abbr. CsPbX3@CA-SiO2) by anchoring CsPbX3 NCs onto silica nanowires (NWs), which effectively depresses the optical degradation of their photoluminescence (PL) and enhances stability. The preparation of surface-functionalized serpentine silica NWs is realized by a sol-gel process involving hydrolysis of a mixture of tetraethylorthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES) and trimethoxy(octadecyl)silane (TMODS) in a water/oil emulsion. The serpentine NWs are formed via an anisotropic growth with lengths up to 8 μm. The free amino groups are employed as surface ligands for growing perovskite NCs, yielding distributed monodisperse NCs (~8 nm) around the NW matrix. The emission wavelength is tunable by simple variation of the halide compositions (CsPbX3, X=Cl, Br or I) and the composites demonstrate a high photoluminescence quantum yield (PLQY 32-69%). Additionally, we have demonstrated the composites CsPbX3@CA-SiO2 can be self-woven to form a porous 3D hierarchical NWs membrane, giving rise to a superhydrophobic surface with hierarchical micro/nano structural features. The resulting composites exhibit high stability towards water, heat and UV irradiation. This work elucidates an effective strategy to incorporate perovskite nanocrystals onto functional matrices as multifunctional stable light sources.
关键词： colloidal CsPbX3 nanocrystal,superhydrophobic,photostability,assembled hierarchical membrane,serpentine silica nanowires
更新于2025-09-04 15:30:14
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An advanced technique of fabricating multi silica directional fiber coupler
摘要： We have investigated the optimum parameter to fabricate multi fiber of silica material for directional coupler based on fusion and elongation techniques. Coupling coefficient between the fibers was derived by using Hankel and Bessel function. However, the fusion temperature was experimentally determined as function of elongation speed. Good performance of multi fiber coupler has been obtained for fabrication parameters of fusion temperature and elongation speed of 1350 oC and 125 μm/s respectively. The proposed coupling coefficient shows a better accuracy with empirical one for various coupling length. It is exponentially increased by reducing the distance between fibers. Finally, the microscopic analysis of coupling region deformation has shown that the silica material was well dispersed and distributed.
关键词： Multi silica fiber coupler,coupling coefficient,fusion and elongation techniques
更新于2025-09-04 15:30:14
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Colorimetric Sensor Array for Monitoring CO and Ethylene
摘要： Developing miniaturized and inexpensive detectors remains an important and practical goal for field-deployable monitoring of toxic gases and other bioactive volatiles. CO (a common toxic pollutant) and ethylene (the phytohormone primarily responsible for fruit ripening) share the capability of strong back-π-bonding to low-oxidation-state metal ions, which has proved important in the development of metal-ion-based sensors for these gases. We report herein cumulative colorimetric sensor arrays based on Pd(II)-silica porous microsphere sensors and their application as an optoelectronic nose for rapid colorimetric quantification of airborne CO and ethylene. Quantitative analysis of two gases was obtained in the range of 0.5 to 50 ppm with detection limits at the sub-parts-per-million level (～0.4 ppm) after 2 min of exposure and ～0.2 ppm after 20 min (i.e., <0.5% of the permissible exposure limit for CO and <10% of the ethylene concentration needed for fruit ripening). We further validate that common potential interfering agents (e.g., changes in humidity or other similar air pollutants such as NOx, SO2, H2S, or acetylene) are not misidentified with CO or ethylene. Finally, the sensor is successfully used for the quantification of ethylene emitted from ripening bananas, demonstrating its potential applications in the monitoring of fruit ripening during storage.
关键词： Pd(II)-silica porous microsphere sensors,CO,ethylene,colorimetric sensor array,optoelectronic nose
更新于2025-09-04 15:30:14