Search Results (386)

The synthesis of lanthanide fluorescent nanoparticles and the investigation of their fluorescence sensing applications have attracted a great deal of attention in materials science over the past decades. In this study, we designed and synthesized a core–shell fluorescent nanoparticle based on dual-center emission from the europium and terbium complexes, and demonstrated its application as a ratiometric fluorescence sensor for the detection of 2,6-pyridinedicarboxylic acid (DPA). The europium complex is embedded in the inner core, providing a stable fluorescence signal at 617 nm, while the terbium complex is positioned in the outer shell and exhibits a fluorescence “Turn-ON” response at 545 nm upon interaction with DPA molecules. The fluorescence intensity ratio F₅₄₅/F₆₁₇ exhibits a sensitive response to the DPA concentration. Experimental results demonstrate that the as-prepared SiO₂@Eu@SiO₂@Tb nanoparticle exhibits a linear response in the DPA concentration range of 10–100 μM, with a detection limit (LOD) of 1.38 μM and well selectivity for DPA sensing. This strategy offers new insights into the development of novel lanthanide-based ratiometric fluorescence sensors. Full article

A green and cost-effective method was employed to efficiently synthesize conductive silica–silver (SiO₂/PCPA/Ag) core–shell structured microspheres. The SiO₂ microspheres were initially functionalized with poly(catechol-polyamine), followed by the in situ reduction of Ag ions to Ag nanoparticles on the surface of the SiO₂ microspheres using an electroless plating process. Analysis using scanning electron microscopy confirmed the successful formation of a dense and uniform silver layer on the surface of the SiO₂ microspheres. The valence state of the silver present on the surface of the SiO₂ microspheres was determined to be zero through analyses conducted using an X-ray photoelectron spectrometer and X-ray diffractometer. Consequently, the SiO₂/PCPA/Ag microspheres, upon initial preparation, demonstrated a notable conductivity of 1005 S/cm, which was further enhanced to 1612 S/cm following additional heat treatment aimed at rectifying defects within the silver layer. The resulting rubber composites displayed a low electrical resistivity of 5.4 × 10⁻³ Ω·cm and exhibited a significant electromagnetic interference (EMI) shielding effectiveness exceeding 100 dB against both X-band and Ku-band frequencies, suggesting promising potential for utilization as a material for conducting and EMI shielding purposes. Full article

Precise remote temperature sensing at the micro- and nanoscale is a growing necessity in modern science and technology. We report a series of luminescent tris-acetylacetonate lanthanide complexes, Ln(acac)₃(H₂O)₂ (Ln = Eu (1Eu), Tb (1Tb), Yb (1Yb)); acac⁻ = acetylacetonate), operating as self-referenced thermometers in the 290–350 K range, both in the solid state and when embedded in hybrid nanoparticles. Among the investigated systems, the Eu³⁺ complex exhibits excellent lifetime-based thermometric performance, achieving a maximum relative sensitivity (S_rmax) of 2.9%·K⁻¹ at 340 K with a temperature uncertainty (δT) as low as 0.02 K and an average temperature uncertainty ($\overline{\delta T}$) of 0.5 K, placing it among the most effective ratiometric lanthanide-based luminescent thermometers reported to date. The Yb³⁺ analog enables intensity-based thermometry in the near-infrared domain with a good sensitivity S_rmax = 0.5%·K⁻¹ at 293 K, δT = 0.5 K at 303 K, and $\overline{\delta T}$ = 1.6 K. These molecular thermometers were further incorporated into the shell of Prussian Blue@SiO₂ core–shell nanoparticles. Among the resulting hybrids, PB@SiO₂-acac/(1Tb/1Eu) (with a Tb/Eu ratio of 2/8) stood out by enabling ratiometric temperature sensing based on the Eu³⁺⁵D₀ → ⁷F₂ lifetime, with satisfactory parameters (S_rmax = 0.9%·K⁻¹, δT = 0.21 K at 303 K, and $\overline{\delta T}$ = 1.1 K). These results highlight the potential of simple coordination complexes and their nanohybrids for advanced luminescent thermometry applications. Full article

Applying therapeutic elements to prevent injury from potential infections is a promising avenue in the development of novel bone substitutes; however, achieving controllable delivery of therapeutic ions is crucial to realizing their expected functions. In this study, a Ag nanoparticle core wrapped in an MSN shell was successfully synthesized using a one-pot sol–gel process. Subsequently, the produced Ag@MSN was functionalized with amino and carboxylic groups. The experimental results indicated that these core–shell-structured Ag@MSN spheres had a uniform size of ~60 nm and a specific area of 904.6 m²/g. Their release profiles, influenced by different surface charges, were investigated, with the aim of achieving sustainable release of Ag ions. The concentration-dependent biological effects of Ag@MSNs, including their anti-infection properties and biocompatibility, were comprehensively characterized in vitro, considering their potential for use as bioactive bone substitutes. Functionalized mesoporous silica nanoparticles significantly enhanced the sustained release profile of silver ions, achieving a cumulative release efficiency greater than 50% within 24 h. These nanoparticles also demonstrated exceptional antibacterial efficacy, with an inhibition rate surpassing 98% at a concentration of 30 μg/mL, while concurrently maintaining cell viability above 88%, indicating high biocompatibility. We achieved our goal of effectively decreasing the burst release of Ag to satisfy the intrinsic need for long-term resistance to bacteria in bone substitutes and stimulate osteoblast proliferation. Full article

This study focuses on the use of almond shell ash (ASA) obtained from agricultural waste through the pyrolysis process in concrete production while, at the same time, presenting an environmentally sustainable design. For this purpose, ASA was obtained from the biomass energy facilities (BEF) for use in concrete mixes. A total of 25 concrete series were prepared, including 1 control series. In these series, 5%, 10%, 15% silica fume (SF), 5%, 10% metakaolin (MK), and 1%, 3%, 5%, and 7% ratios of ASA were chosen to be substituted by volume with cement. Fresh and hardened concrete tests were performed on the specimens. Experiments have shown that the use of ASA in concrete production improves concrete performance up to a certain extent. With the data obtained from the test results, performance evaluation was performed in the artificial neural network. Because of this evaluation, a mathematical model able to predict the concrete compressive strength with high accuracy was developed. To evaluate the effectiveness of the developed model, it was tested again on control specimens to confirm its accuracy and applicability. A life cycle assessment (LCA) was also performed. The aim is to make a new contribution to the literature and practical application with the method to be developed because of the study and to pioneer future studies in this field. Full article

In this work, alkylammonium-functionalized hollow mesoporous silica as a nonocarrier of drugs was synthesized to realize enhanced cancer therapy by pH stimuli for sustained drug release. First, functionalized hollow mesoporous silica nanoparticles (Hollow MSNs) were synthesized using dodecyl dimethyl(3-sulfopropyl)ammonium hydroxide (DDAPS), sodium dodecyl sulfate (SDS), and triethanolamine as structure-directing agents, while tetraethyl orthosilicate (TEOS) and N-trimethoxysilypropyl-N,N,N-trimethylammonium chloride (TMAPS) were used as silica sources under basic condition via the sol–gel process. The structure and morphology of the alkylammonium-functionalized hollow mesoporous silica nanoparticles (Hollow MSN-N⁺CH₃) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption analysis, and Fourier transform infrared (FT-IR) spectroscopy. The functionalized hollow MSNs had a particle size of about 450 nm and a shell thickness of about 60 nm with uniform size. The nanoparticle had a surface area of 408 m²g⁻¹, pore volume of 0.8 cm³g⁻¹, and a uniform pore diameter of 45.9 Å. In the cancer cell viability test with a MCF-7 cell, fludarabine-incorporated and alkylammonium-functionalized hollow mesoporous silica nanoparticles (Flu/Hollow MSN-N⁺CH₃) showed excellent cancer cell death comparable with pure fludarabine drug with the controlled drug release by pH stimuli. It is suggested that our current materials have potential applicability as pH-responsive nanocarriers in the field of cancer therapy. Full article

Lost circulation, a prevalent challenge in drilling engineering, poses significant risks including drilling fluid loss, wellbore instability, and environmental contamination. Conventional plugging materials often exhibit an inadequate performance under high-temperature, high-pressure (HTHP), and complex formation conditions. To address that, this study developed a high-performance gel–resin composite plugging material resistant to HTHP environments. By optimizing the formulation of bisphenol-A epoxy resin (20%), hexamethylenetetramine (3%), and hydroxyethyl cellulose (1%), and incorporating fillers such as nano-silica and walnut shell particles, a controllable high-strength plugging system was constructed. Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the structural stability of the resin, with an initial decomposition temperature of 220 °C and a compressive strength retention of 14.4 MPa after 45 days of aging at 140 °C. Rheological tests revealed shear-thinning behavior (initial viscosity: 300–350 mPa·s), with viscosity increasing marginally to 51 mPa·s after 10 h of stirring at ambient temperature, demonstrating superior pumpability. Experimental results indicated excellent adaptability of the system to drilling fluid contamination (compressive strength: 5.04 MPa at 20% dosage), high salinity (formation water salinity: 166.5 g/L), and elevated temperatures (140 °C). In pressure-bearing plugging tests, the resin achieved a breakthrough pressure of 15.19 MPa in wedge-shaped fractures (inlet: 7 mm/outlet: 5 mm) and a sand-packed tube sealing pressure of 11.25 MPa. Acid solubility tests further demonstrated outstanding degradability, with a 97.69% degradation rate after 24 h in 15% hydrochloric acid at 140 °C. This study provides an efficient, stable, and environmentally friendly solution for mitigating drilling fluid loss in complex formations, exhibiting significant potential for engineering applications. Full article

Cervical cancer represents a significant global health challenge. Photodynamic therapy (PDT) appears to be a promising, minimally invasive alternative to standard treatments. However, the clinical efficacy of PDT is sometimes limited by the low solubility and aggregation of photosensitizers, their non-selective distribution in the body, hypoxia in the tumor microenvironment, and limited light penetration. Recent advances in nanoparticle and nanocomposite platforms have addressed these challenges by integrating multiple functional components into a single delivery system. By encapsulating or conjugating photosensitizers in biodegradable matrices, such as mesoporous silica, organometallic structures and core–shell construct nanocarriers increase stability in water and extend circulation time, enabling both passive and active targeting through ligand decoration. Up-conversion and dual-wavelength responsive cores facilitate deep light conversion in tissues, while simultaneous delivery of hypoxia-modulating agents alleviates oxygen deprivation to sustain reactive oxygen species generation. Controllable “motor-cargo” constructs and surface modifications improve intratumoral diffusion, while aggregation-induced emission dyes and plasmonic elements support real-time imaging and quantitative monitoring of therapeutic response. Together, these multifunctional nanosystems have demonstrated potent cytotoxicity in vitro and significant tumor suppression in vivo in mouse models of cervical cancer. Combining targeted delivery, controlled release, hypoxia mitigation, and image guidance, engineered nanoparticles provide a versatile and powerful platform to overcome the current limitations of PDT and pave the way toward more effective, patient-specific treatments for cervical malignancies. Our review of the literature summarizes studies on nanoparticles and nanocomposites used in PDT monotherapy for cervical cancer, published between 2023 and July 2025. Full article

This study reports the development of a sustainable biocatalyst system for free fatty acid (FFA) production from cocoa bean shell (CBS) oil using Burkholderia cepacia lipase (BCL). CBS was explored as both a support material and a reaction substrate. Six immobilized systems were prepared using organic (CBS), inorganic (silica), and hybrid (CBS–silica) supports via physical adsorption or covalent binding. Among them, the covalently immobilized enzyme on CBS (ORG-CB) showed the most balanced performance, achieving a catalytic efficiency (Ke) of 0.063 mM⁻¹·min⁻¹ (18.6% of the free enzyme), broad pH–temperature tolerance, and over 50% activity retention after eight reuse cycles. Thermodynamic analysis confirmed enhanced thermal resistance for ORG-CB (Ed = 32.3 kJ mol⁻¹; ΔH‡ = 29.7 kJ mol⁻¹), while kinetic evaluation revealed that its thermal deactivation occurred faster than for the free enzyme under prolonged heating. In application trials, ORG-CB reached 60.1% FFA conversion from CBS oil, outperforming the free enzyme (49.9%). These findings validate CBS as a dual-function material for enzyme immobilization and valorization of agro-industrial waste. The results also reinforce the impact of immobilization chemistry and support composition on the operational and thermal performance of biocatalysts, contributing to the advancement of green chemistry strategies in enzyme-based processing. Full article

Co-infections pose significant challenges not only clinically, but also in terms of simultaneous diagnoses. The development of sensitive, multiplexed analytical platforms is critical for accurately detecting viral co-infections, particularly in complex biological environments. In this study, we present a mass spectrometry (MS)-based detection strategy employing a target-triggered hybridization chain reaction (HCR) to amplify signals and in situ photocleavable mass tags (PMTs) for the simultaneous detection of multiple targets. Hairpin DNAs modified with PMTs and immobilized loop structures on magnetic particles (Loop@MPs) were engineered for each target, and their hybridization and amplification efficiency was validated using native polyacrylamide gel electrophoresis (PAGE) and laser desorption/ionization MS (LDI-MS), with silica@gold core–shell hybrid (SiAu) nanoparticles being employed as an internal standard to ensure quantitative reliability. The system exhibited excellent sensitivity, with a detection limit of 415.12 amol for the hepatitis B virus (HBV) target and a dynamic range spanning from 1 fmol to 100 pmol. Quantitative analysis in fetal bovine serum confirmed high accuracy and precision, even under low-abundance conditions. Moreover, the system successfully and simultaneously detected multiple targets, i.e., HBV, human immunodeficiency virus (HIV), and hepatitis C virus (HCV), mixed in various ratios, demonstrating clear PMT signals for each. These findings establish our approach as a robust and reliable platform for ultrasensitive multiplexed detection, with strong potential for clinical and biomedical research. Full article

The limited oxidation resistance of MoSi₂ between 400 °C and 600 °C restricts its aerospace applications. This study develops a silica-sol derived core-shell MoSi₂@SiO₂ composite to enhance the low-temperature oxidation resistance of MoSi₂. Acidic, neutral, and basic silica sols were systematically applied to coat MoSi₂ powders through sol-adsorption encapsulation. Two pathways were used, one was ethanol-mediated dispersion, and the other was direct dispersion of MoSi₂ particles in silica sol. Analysis demonstrated that ethanol-mediated dispersion significantly influenced the coating efficiency and oxidation resistance, exhibited significantly decreased coating weight gains (maximum 27%) and increased oxidation weight gains (10–20%) between 340 °C and 600 °C compared with direct dispersion of MoSi₂ particles with silica sol, ascribe to the kinetic inhibition of hydroxyl group condensation and steric hindrance of MoSi₂-silica sol interface interactions of ethanol. Systematic investigation of silica sol encapsulation of MoSi₂ revealed critical correlations between colloid properties and oxidation resistance of MoSi₂@SiO₂. Basic silica sol coated MoSi₂ (BS-MoSi₂) exhibits the lowest coating efficiency (coating weight gain of 7.74 ± 0.06%) as well as lowest oxidation weight gain (18.45%) between 340 °C and 600 °C compared with those of acid and neutral silica sol coated MoSi₂ (AS-MoSi₂ and NS-MoSi₂), arises from optimal gelation kinetics, enhanced surface coverage via reduced agglomeration, and suppressed premature nucleation through controlled charge interactions under alkaline conditions. Full article

The pore structure of a hydrotreating catalyst plays a pivotal role in hydrodemetallization (HDM) reactions. To effectively construct a meso-macroporous catalyst, we employed a CTAB-guided in situ TEOS hydrolysis approach to prepare silica-coated γ-Al₂O₃@SiO₂ composite supports. The silica shell incorporation significantly enhances specific surface area and reduces the metal–support interactions, thereby improving the dispersion of NiMo active components and boosting the deposition of metal impurity. Hence, the NiMo/Al₂O₃@SiO₂ catalyst (2.8 wt.% NiO, 4.3 wt.% MoO₃) exhibits much higher HDM activity than that of NiMo/Al₂O₃. This is evidenced by markedly higher demetallization rate constant (1.38 h⁻¹) and turnover frequency (0.56 h⁻¹) of the NiMo/Al₂O₃@SiO₂. The NiMo/Al₂O₃@SiO₂ catalyst further demonstrates excellent recyclability during sequential HDM reactions. This superior catalytic behavior stems from the hierarchical meso-macroporous structure, which simultaneously facilitates the deposition of metal impurities and mitigates deactivation by pore blockage. Full article

In this study, an innovative dental functionalized magnetic nanomaterial was developed by incorporating hydrophilic magnetic clusters as an alternative to conventional isolated magnetic nanoparticles, introducing a novel structural and functional concept in dental applications. The ~100 nm magnetic clusters—composed of densely packed 7 nm Fe₃O₄ nanoparticles—were sequentially coated with a silica (SiO₂) layer (3–5 nm) to improve chemical and mechanical stability, followed by an outer calcium hydroxide [Ca(OH)₂] layer to enhance bioactivity and optical integration. This bilayer architecture enables magnetic field-assisted positioning and improved dispersion within dental resin matrices. Silver nanoparticles were incorporated to enhance antimicrobial activity and reduce biofilm formation. The synthesis process was environmentally friendly and scalable. Comprehensive physicochemical characterization confirmed the material’s functional performance. Saturation magnetization decreased progressively with surface functionalization, from 62 to 14 emu/g, while the zeta potential became increasingly negative (from −2.42 to −22.5 mV), supporting its ability to promote apatite nucleation. The thermal conductivity (0.527 W/m·K) closely matched that of human dentin (0.44 W/m·K), and the colorimetric analysis showed improved brightness (ΔL = 5.3) and good color compatibility (ΔE = 11.76). These results indicate that the functionalized magnetic nanomaterial meets essential criteria for restorative use and holds strong potential for future clinical applications. Full article

The development of mineral, biodegradable sunscreens that can offer both high photoprotection and long-term colloidal stability, while limiting synthetic additives, presents a significant challenge. A linseed oil nanoemulsion co-stabilised by ZnO nanoparticles and the eco-friendly surfactant Appyclean 6552 was formulated, and the effect of incorporating fumed silica/alumina (Aerosil COK 84) was evaluated. A central composite response surface design was used to ascertain the oil/ZnO ratio that maximised the in vitro sun protection factor at sub-300 nm droplet size. The incorporation of Aerosil at concentrations ranging from 0 to 2 wt.% resulted in a transformation of the dispersion from a nearly Newtonian state to a weak-gel behaviour. This alteration was accompanied by a reduction in the Turbiscan Stability Index. Microscopic analysis has revealed a hierarchical particle architecture, in which ZnO forms Pickering shells around each droplet, while Aerosil aggregates bridge neighboring interfaces, creating a percolated silica scaffold that immobilises droplets and amplifies multiple UV scattering. The findings demonstrate that coupling interfacial Pickering armour with a continuous silica network yields a greener, physically robust mineral sunscreen and offers a transferable strategy for stabilising plant-oil emulsions containing inorganic actives. Full article

The hypoxic microenvironment is the main challenge for the repair of damaged tissue, and oxygen supply is an effective means of alleviating hypoxia. In this study, a series of core–shell-structured calcium peroxide/poly(ethylene glycol)@silica (CPO@SiO₂) nanoparticles are prepared to generate oxygen steadily. The size of the CPO@SiO₂ nanoparticles ranges from 205 to 302 nm, with a narrow polydispersity index (PDI). In this system, the nano CPO core acts as the oxygen source to improve hypoxia, while the SiO₂ shell layer serves as the physical barrier to control the oxygen-generating rate and improve biocompatibility. The results suggest that the thickness of the SiO₂ shell layer can be modulated by adjusting the amount of tetraethyl orthosilicate (TEOS). The prepared CPO@SiO₂ nanoparticles show a controlled oxygen-generating rate. Moreover, compared with CPO, the CPO@SiO₂ nanoparticles have good biocompatibility. To assess the modulating effects for the hypoxic microenvironment, L929 cells are co-cultured with CPO@ SiO₂ nanoparticles under hypoxia. The results suggest that the CPO@ SiO₂ nanoparticles can support the cell survival under hypoxia. Moreover, they can effectively decrease oxidative stress damage and reduce the levels of expression of hypoxia-induced superoxide dismutase (SOD) and malondialdehyde (MDA). Therefore, the prepared CPO@ SiO₂ nanoparticles with controlled oxygen-generating properties could be a promising candidate for repairing damaged tissue. Full article