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Perspectives on the adsorption of CO2 on amine-modified silica studied by infrared spectroscopy
摘要： Amine-modified adsorbents are being researched for their potential to capture CO2 from various gas mixtures, and we review how IR spectroscopy has been used to study the associated CO2–amine chemistry. It has been used to reveal that CO2 chemisorbs as ammonium-carbamate ion pairs especially when the amine density is high. Carbamic acid and related other moieties tend to form in parallel to the ion pairs when the amine density is low. The amines have been shown to degrade on cyclic heat treatment. To further study the formation of bicarbonates on reactive adsorption of CO2 and H2O, degradation of the organics, and the use of other supports than silica are suggested.
关键词： porous materials,FT-IR spectroscopy,amine-modified silica,carbon capture,CO2 adsorption
更新于2025-09-23 15:21:01
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Photodynamic application of protoporphyrin IX as a photosensitizer encapsulated by silica nanoparticles
摘要： Background: Achieved Silica Nanoparticles (SiNPs) to encapsulate the photosensitizer [Protoporphyrin IX (PpIX)] in photodynamic therapy (PDT) application was reported in this research. Materials and Methods: Cytotoxicity for five different concentrations of encapsulated and naked PpIX was measured. Optimum concentration and optimum exposure time of encapsulated and naked PpIX that needed to destroy the cells (Osteosarcoma cells) was measured. Results: The results showed that the encapsulated PpIX has more efficacy compared to the naked PpIX and the applicability of the encapsulated PpIX-SiNPs was proved on osteosarcoma cells. Conclusion: The results established the important in-vitro photodynamic effectiveness of PpIX-SiNP, which may open a new application for PpIX in its clinical and in-vitro studies.
关键词： encapsulation,osteosarcoma cells,protoporphyrin IX,silica nanoparticles,Photodynamic therapy
更新于2025-09-23 15:21:01
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Mesoporous multi-silica layer-coated Y2O3:Eu core-shell nanoparticles: Synthesis, luminescent properties and cytotoxicity evaluation
摘要： Mesoporous multi-layered silica-coated luminescent Y2O3:Eu nanoparticles (NPs) were prepared by a urea-based decomposition process, and their surfaces were gradually modified with nanoporous and mesoporous silica layers using modified sol-gel methods. The synthesized luminescent core-shell NPs were characterized thoroughly to investigate their structural, morphological, thermal, optical, photo luminescent properties and their surface chemistry. The morphology of the core NPs were nearly spherical in shape and were nano-sized grains. The observed luminescent efficiency of the mesoporous multi-layered silica-coated luminescent core NPs was gradually reduced because of bond formation between the Y2O3:Eu core and the amorphous silica shell via YeOeSieOH bridges on the surface of the NPs; the bonds suppressed the non-radiative transition pathways. Biocompatibility tests on human breast cancer cells using the 3?(4,5?Dimethylthiazol?2?yl)?2,5?diphenyltetrazolium bromide and lactate dehydrogenase assays indicated that the core-shell NPs were non-toxic even at high concentrations. The mesoporous SiO2 layer played a key role in perfecting the solubility, biocompatibility, and non-toxicity of the NPs. The zeta potential, surface chemistry (Fourier transform infrared spectroscopy), and optical absorption spectral analyses revealed the high hydrophilicity of the as-prepared core-shell NPs because of the active surface-functionalized silanol (SieOH) groups, which could potentially offer many exciting opportunities in photonic-based biomedical applications.
关键词： Cytotoxicity,Mesoporous silica shell,Photoluminescence,Yttrium oxide,Raman spectra,Biocompatibility
更新于2025-09-23 15:21:01
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Contents: (Adv. Funct. Mater. 44/2018)
摘要： Silica nanofibrous membranes produced by direct electrospinning of a sol-gel solution without a sacrificing polymer allow high-end separation and purification due to a high thermal and chemical resistance. The water repellent or absorbing nature can be tuned by applying a humidity or thermal treatment. It is showcased that fast gravity driven membrane separation of heterogeneous azeotropes can be achieved.
关键词： thermal resistance,chemical resistance,sol-gel,electrospinning,azeotrope separation,silica nanofibrous membranes
更新于2025-09-23 15:21:01
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Amine-functionalized, porous silica-coated NaYF4:Yb/Er upconversion nanophosphors for efficient delivery of doxorubicin and curcumin
摘要： Upconversion nanoparticles (UCNP) with unique multi-photon excitation photo-luminescence properties have been extensively explored as novel contrast agents for low-background biomedical imaging. There is an increasing interest in employing UCNPs as carrier for drug delivery as these offers a unique opportunity to combine therapy and diagnostics in one platform (theranostics). In the present work, we report microwave-assisted synthesis of hexagonal NaYF4:Yb/Er UCNPs coated with porous silica and functionalized with amine (UCNP@mSiO2). The UCNP@mSiO2 were investigated for controlled delivery of a chemotherapeutic agent, doxorubicin (DOX, hydrophilic), and a chemosensitizing agent, curcumin (CCM, hydrophobic). The drug loading was relatively higher for DOX (17.4%), in comparison to CCM (8.1%). The cumulative drug release from DOX-loaded UCNP@mSiO2 were 30 and 41% at physiological (7.4) and tumoral (6.4) pH, following a pseudo Fickian release pattern, whereas the release from CCM-loaded UCNP@mSiO2 were 27 and 50% at pH 7.4 and 6.4, following a non-Fickian and pseudo-Fickian release patterns. Both DOX and CCM-loaded UCNP@mSiO2 exhibited pH-dependent controlled drug delivery but the effect was more pronounced for CCM, the hydrophobic chemosensitizer. Cell viability assay using HeLa cells showed that DOX-loaded UCNP@mSiO2 inhibit cell growth in a dose-dependent manner, similar to free DOX, but the cell inhibition activity of free CCM was lower than CCM passively entrapped in UCNP@mSiO2. Confocal microscopy studies revealed cell uptake of both the drug by HeLa cells. Thus, UCNP@mSiO2 exhibited the unique capability to deliver hydrophilic and hydrophobic drugs, individually. UCNP@mSiO2 carrier, equipped with theranostic capabilities, may potentially be used for pH-responsive release of chemotherapeutic agents in cancer environment.
关键词： curcumin,porous silica,doxorubicin,drug delivery,Upconversion nanoparticles
更新于2025-09-23 15:21:01
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A Biomimetic Plasmonic Nanoreactor for Reliable Metabolite Detection
摘要： Reliable monitoring of metabolites in biofluids is critical for diagnosis, treatment, and long-term management of various diseases. Although widely used, existing enzymatic metabolite assays face challenges in clinical practice primarily due to the susceptibility of enzyme activity to external conditions and the low sensitivity of sensing strategies. Inspired by the micro/nanoscale confined catalytic environment in living cells, the coencapsulation of oxidoreductase and metal nanoparticles within the nanopores of macroporous silica foams to fabricate all-in-one bio-nanoreactors is reported herein for use in surface-enhanced Raman scattering (SERS)-based metabolic assays. The enhancement of catalytical activity and stability of enzyme against high temperatures, long-time storage or proteolytic agents are demonstrated. The nanoreactors recognize and catalyze oxidation of the metabolite, and provide ratiometric SERS response in the presence of the enzymatic by-product H2O2, enabling sensitive metabolite quantification in a “sample in and answer out” manner. The nanoreactor makes any oxidoreductase-responsible metabolite a candidate for quantitative SERS sensing, as shown for glucose and lactate. Glucose levels of patients with bacterial infection are accurately analyzed with only 20 μL of cerebrospinal fluids, indicating the potential application of the nanoreactor in vitro clinical testing.
关键词： metabolic assays,metabolic testing,macroporous silica foams,biomimetic nanoreactors,SERS biosensors,enzymes
更新于2025-09-23 15:19:57
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Damage characteristics of laser plasma shock wave on rear surface of fused silica glass
摘要： The damage to the rear surface of fused silica under the action of high power laser is more severe than that incurred by the front surface, which hinders the improvement in the energy of the high power laser device. For optical components, the ionization breakdown by laser is a main factor causing damage, particularly with laser plasma shock waves, which can cause large-scale fracture damage in fused silica. In this study, the damage morphology is experimentally investigated, and the characteristics of the damage point are obtained. In the theoretical study, the coupling and transmission of the shock wave in glass are investigated based on the ?nite element method. Thus, both the magnitude and the orientation of stress are obtained. The damage mechanism of the glass can be explained based on the fracture characteristics of glass under different stresses and also on the variation of the damage zone’s Raman spectrum. In addition, the in?uence of the glass thickness on the damage morphology is investigated. The results obtained in this study can be used as a reference in understanding the characteristics and mechanism of damage characteristics induced by laser plasma shock waves.
关键词： different thickness,Raman spectroscopy,rear surface of fused silica,laser-induced plasma,?nite element method
更新于2025-09-23 15:19:57
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Two-photon pumped spaser based on the CdS/ZnS core/shell quantum dota??mesoporous silicaa??metal structure
摘要： The spaser (a plasmonic nanolaser) has rapidly advanced as a subwavelength light source candidate. Herein, we introduce a spaser based on a quantum-dot, mesoporous-oxide, and metal structure from top to bottom consisting of CdS/ZnS core/shell quantum dots, a mesoporous silica film (MSF), and an Au film, respectively. Two-photon pumping using femtosecond laser pulses at 800 nm creates amplified spontaneous emission at approximately 451 nm. The advantages of MSF as a dielectric gap layer are examined through numerical simulations. Measuring the dependence of the luminescence intensity on the average pump power confirms the occurrence of two-photon up-conversion luminescence.
关键词： spaser,two-photon pumping,mesoporous silica film,plasmonic nanolaser,quantum dots
更新于2025-09-23 15:19:57
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Target-responsive ratiometric fluorescent aptasensor for OTA based on energy transfer between [Ru(bpy)3]2+ and silica quantum dots
摘要： A ratiometric fluorescent aptasensor based on energy transfer between [Ru(bpy)3]2+ and silica quantum dots (silica QDs) for assaying OTA was fabricated. The aptamer for OTA was used as the gate to shield the fluorescent reagent [Ru(bpy)3]2+ into mesoporous silica nanoparticle (MSN). In the presence of OTA, the constrained [Ru(bpy)3]2+ was released from MSN due to a target-induced aptamer conformational change. The released [Ru(bpy)3]2+ adsorbed onto the negatively charged silica QDs through electrostatic interaction. This creates appearance of fluorescence from [Ru(bpy)3]2+ at 625 nm and decrease of the fluorescence from silica QDs at 442 nm owing to the energy transfer. The value of FL625nm/FL442nm was in proportion to the concentration of OTA in the range 0.5~100 ng mL?1 with a LOD of 0.08 ng mL?1. Practical applicability of this method was validated by the determination of OTA in flour samples.
关键词： Ochratoxin A,Ratiometric fluorescent sensor,Aptamer,Silica quantum dots,[Ru(bpy)3]2+
更新于2025-09-23 15:19:57
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Features of fused silica ablation by laser induced carbon microplasma
摘要： The features of surface structuring on the transparent material by laser-induced microplasma were studied and the intensity of its microplasma was measured. The formation of micro-relief by a series of nanosecond pulsed laser induced carbon microplasma in confinement mode on the surface of fused silica were investigated and the measured intensity was compared with the features of micro-relief. The dependence of depth of formed relief and track on the laser regime was determined. It is shown that the mechanism of microstructure formation is dependent on multifactor and associated with the ablation on the surface of fused silica by the microplasma, which exists quite long time after the pulses.
关键词： Ablation,Surface structuring,Laser-induced microplasma,Nanosecond pulses,Fiber laser,Fused silica
更新于2025-09-23 15:19:57