Mesoporous Silicon Research Articles

A comprehensive review on metal based active sites and their interaction with O3 during heterogeneous catalytic ozonation process: Types, regulation and authentication.

Heterogeneous catalytic ozonation (HCO) was a promising water purification technology. Designing novel metal-based catalysts and exploring their structural-activity relationship continued to be a hot topic in HCO. Herein, we reviewed the recent development of metal-based catalysts (including monometallic and polymetallic catalysts) in HCO. Regulation of metal based active sites (surface hydroxyl groups, Lewis acid sites, metal redox cycle and surface defect) and their key roles in activating O3 were explored. Advantage and disadvantage of conventional characterization techniques on monitoring metal active sites were claimed. In situ electrochemical characterization and DFT simulation were recommended as supplement to reveal the metal active species. Though the ambiguous interfacial behaviors of O3 at these active sites, the existence of interfacial electron migration was beyond doubt. The reported metal-based catalysts mainly served as electron donator for O3, which resulted in the accumulation of oxidized metal and reduced their activity. Design of polymetallic catalysts could accelerate the interfacial electron migration, but they still faced with the dilemma of sluggish Me(n+m)+/Men+ redox cycle. Alternative strategies like coupling active metal species with mesoporous silicon materials, regulating surface hydrophobic/hydrophilic properties, polaring surface electron distribution, coupling HCO process with photocatalysis and H2O2 were proposed for future research.

A spatiotemporal drug release scaffold with antibiosis and bone regeneration for osteomyelitis

IntroductionScaffolds loaded with antibacterial agents and osteogenic drugs are considered essential tools for repairing bone defects caused by osteomyelitis. However, the simultaneous release of two drugs leads to premature osteogenesis and subsequent sequestrum formation in the pathological situation of unthorough antibiosis. ObjectivesIn this study, a spatiotemporal drug-release polydopamine-functionalized mesoporous silicon nanoparticle (MSN) core/shell drug delivery system loaded with antibacterial silver (Ag) nanoparticles and osteogenic dexamethasone (Dex) was constructed and introduced into a poly-l-lactic acid (PLLA) scaffold for osteomyelitis therapy. MethodsMSNs formed the inner core and were loaded with Dex through electrostatic adsorption (MSNs@Dex), and then polydopamine was used to seal the core through the self-assembly of dopamine as the outer shell (pMSNs@Dex). Ag nanoparticles were embedded in the polydopamine shell via an in situ growth technique. Finally, the Ag-pMSNs@Dex nanoparticles were introduced into PLLA scaffolds (Ag-pMSNs@Dex/PLLA) constructed by selective laser sintering (SLS). ResultsThe Ag-pMSNs@Dex/PLLA scaffold released Ag+ at the 12th hour, followed by the release of Dex starting on the fifth day. The experiments verified that the scaffold had excellent antibacterial performance against Escherichia coli and Staphylococcus aureus. Moreover, the scaffold significantly enhanced the osteogenic differentiation of mouse bone marrow mesenchymal stem cells. ConclusionThe findings suggested that this spatiotemporal drug release scaffold had promising potential for osteomyelitis therapy.

Synergistic Pro-Apoptotic Effect of a Cyclic RGD Peptide-Conjugated Magnetic Mesoporous Therapeutic Nanosystem on Hepatocellular Carcinoma HepG2 Cells.

Numerous nanocarriers have been developed to deliver drugs for the treatment of hepatocellular carcinoma. However, the lack of specific targeting ability, the low administration efficiency, and insufficient absorption by hepatocellular carcinoma cells, severely limits the therapeutic effect of the current drugs. Therefore, it is still of great clinical significance to develop highly efficient therapies with few side effects for the treatment of hepatocellular carcinoma. Herein, we developed a highly effective nanocarrier, cyclic RGD peptide-conjugated magnetic mesoporous nanoparticles (RGDSPIO@MSN NPs), to deliver the chemotherapeutic drug doxorubicin (DOX) to human hepatocellular carcinoma HepG2 cells, and further explored their synergistic apoptosis-promoting effects. The results showed that the prepared RGDSPIO@MSN NPs had good stability, biosafety and drug-loading capacity, and significantly improved the absorption of DOX by HepG2 cells, and that the RGDSPIO@MSN@DOX NPs could synergistically promote the apoptosis of HepG2 cells. Thus, this cyclic RGD peptide-modified magnetic mesoporous silicon therapeutic nanosystem can be regarded as a potentially effective strategy for the targeted treatment of hepatocellular carcinoma.

Antibacterial Effect of Acoustic Cavitation Promoted by Mesoporous Silicon Nanoparticles.

As-prepared mesoporous silicon nanoparticles, which were synthesized by electrochemical etching of crystalline silicon wafers followed by high-energy milling in water, were explored as a sonosensitizer in aqueous media under irradiation with low-intensity ultrasound at 0.88 MHz. Due to the mixed oxide-hydride coating of the nanoparticles' surfaces, they showed both acceptable colloidal stability and sonosensitization of the acoustic cavitation. The latter was directly measured and quantified as a cavitation energy index, i.e., time integral of the magnitude of ultrasound subharmonics. The index turned out to be several times greater for nanoparticle suspensions as compared to pure water, and it depended nonmonotonically on nanoparticle concentration. In vitro tests with Lactobacillus casei revealed a dramatic drop of the bacterial viability and damage of the cells after ultrasonic irradiation with intensity of about 1 W/cm2 in the presence of nanoparticles, which themselves are almost non-toxic at the studied concentrations of about 1 mg/mL. The experimental results prove that nanoparticle-sensitized cavitation bubbles nearby bacteria can cause bacterial lysis and death. The sonosensitizing properties of freshly prepared mesoporous silicon nanoparticles are beneficial for their application in mild antibacterial therapy and treatment of liquid media.

Manufacture of Mesoporous Silicon Microparticles (MSMPs) as Adjuvants for Vaccine Delivery.

The advent of computational approaches has accelerated the identification of vaccine candidates like epitope peptides. However, epitope peptides are usually very poorly immunogenic and adequate platforms are required with adjuvant capacity to verity immunogenicity and antigenicity of vaccine subunits in vivo. Silicon microparticles are being developed as potential new adjuvants for vaccine delivery due to their physicochemical properties. This chapter explains the methodology to fabricate and functionalize mesoporous silicon microparticles (MSMPs) which can be loaded with antigens of different nature, such as viral peptides, proteins, or carbohydrates, and this strategy is particularly suitable for delivery of epitopes identified by computer.

ПЕРСПЕКТИВА ПРИМЕНЕНИЯ ГИБРИДНОГО ПОРОШКОВОГО МАТЕРИАЛА AgI-SiO2 В СОСТАВЕ ПРОТИВОГРАДОВОГО РАКЕТНОГО ТОПЛИВА

The work proposes new hybrid powder materials as sediment-converting reagents used in geoengineering technologies (technologies for artificial precipitation management). Hybrid powder materials AgI-SiO2 are mesophase mesoporous silicon dioxide with silver iodide. They were obtained through the “Paste Formation” process, which involves constant mixing of an aqueous condensed suspension of silicon dioxide of various types with the sequential addition of silver nitrate and potassium iodide. The characteristic features of the synthesized AgI-SiO2 hybrids were studied using instrumental methods of analysis: structural, textural and rheological parameters. The influence of hybrid powder material AgI-SiO2 (HPs) on the efficiency of anti-hail rocket fuel is shown using the TERRA software system for modeling phase and chemical equilibrium at high temperatures. It is certain that using HPs AgI-SiO2 as part of anti-hail rocket fuel leads to an increase in the amount of condensed phase, including active forms of silver iodide. This active form of AgI is required for the implementation of ice formation processes in the cloud. An increase in the amount of the β-form of AgI in the composition of the initial HPs was shown compared to pure silver iodide using X-ray phase (XRF) analysis and differential scanning calorimetry. It was established that silver iodide in the hybrid has greater thermal stability, as evidenced by the characteristic peaks of crystalline forms. HPs AgI-SiO2 will improve the efficiency of anti-hail rocket fuel by increasing the number of ice formation and condensation centers, because they exhibit several mechanisms of action on atmospheric moisture. The synthesized hybrid powders meet the requirements of the regulatory documents in force in the Russian Federation

Effect of nanoparticles of different stiffness combined with menthol/curcumol on mechanical properties of bEnd.3 cells

This study aimed to investigate the effects of nanoparticles PLGA-NPs and mesoporous silicon nanoparticles(MSNs) of different stiffness before and after combination with menthol or curcumol on the mechanical properties of bEnd.3 cells. The particle size distributions of PLGA-NPs and MSNs were measured by Malvern particle size analyzer, and the stiffness of the two nanoparticles was quantified by atomic force microscopy(AFM). The bEnd.3 cells were cultured in vitro, and the cell surface morphology, roughness, and Young's modulus were examined to characterize the roughness and stiffness of the cell surface. The changes in the mechanical properties of the cells were observed by AFM, and the structure and expression of cytoskeletal F-actin were observed by a laser-scanning confocal microscope. The results showed that both nanoparticles had good dispersion. The particle size of PLGA-NPs was(98.77±2.04) nm, the PDI was(0.140±0.030), and Young's modulus value was(104.717±8.475) MPa. The particle size of MSNs was(97.47±3.92) nm, the PDI was(0.380±0.016), and Young's modulus value was(306.019±8.822) MPa. The stiffness of PLGA-NPs was significantly lower than that of MSNs. After bEnd.3 cells were treated by PLGA-NPs and MSNs separately, the cells showed fine pores on the cell surface, increased roughness, decreased Young's modulus, blurred and broken F-actin bands, and reduced mean gray value. Compared with PLGA-NPs alone, PLGA-NPs combined with menthol or curcumol could allow deepened and densely distributed surface pores of bEnd.3 cells, increase roughness, reduce Young's modulus, aggravate F-actin band breakage, and diminish mean gray value. Compared with MSNs alone, MSNs combined with menthol could allow deepened and densely distributed surface pores of bEnd.3 cells, increase roughness, reduce Young's modulus, aggravate F-actin band breakage, and diminish mean gray value, while no significant difference was observed in combination with curcumol. Therefore, it is inferred that the aromatic components can increase the intracellular uptake and transport of nanoparticles by altering the biomechanical properties of bEnd.3 cells.

Mn2O3 nanoparticle-porous silicon nanocomposite based amperometric sensor for sensitive detection and quantification of Acetaminophen in real samples

Acetaminophen (AcP) commonly known as paracetamol is the most extensively used non-prescribed medication for the treatment of fever and different kinds of pain. Due to the wide range of use, the determination of AcP contents in commercial tablets, residual AcP present in human blood serum, and the presence of AcP in the environment from the unavoidable leakage during the industrial production becomes crucial. Therefore, we proposed an AcP sensor utilizing a novel Mn 2 O 3 -embedded mesoporous silicon (Mn 2 O 3 @PSi) nanocomposite fabricated glassy carbon electrode (GCE). Modern characterization techniques including FESEM, TEM, EDXS, XRD, XPS, and FTIR spectroscopy were employed to characterize the fabricated Mn 2 O 3 @PSi nanocomposite. XRD and XPS analysis confirmed the fruitful development of nanocomposite consisting of PSi, and Mn 2 O 3 . TEM images revealed that Mn 2 O 3 nanoparticles were randomly distributed onto the PSi matrix. In the electrochemical investigations via the most reliable amperometric technique, the Mn 2 O 3 @PSi/GCE sensor showed excellent sensitivity (0.7948 μAμM −1 cm −2 ), a wide LDR (0.3–138.7 μM), and a very low detection limit (LOD ∼0.033 μM). The newly developed AcP sensor was further used to check the potential chemical interference using several closely related chemicals, presenting an extreme selectivity towards the AcP detection. The Mn 2 O 3 @PSi/GCE sensor electrode was also employed to determine the AcP in commercial paracetamol tablets and showed ∼100% quantitative recovery. During the AcP determination, the Mn 2 O 3 @PSi/GCE sensor also displayed excellent reproducibility, repeatability, and stability. It is anticipated that this Mn 2 O 3 @PSi/GCE assembly will emerge as an efficient route in developing an effective AcP sensor.

Identification of yeast α-glucosidase inhibitors from Pueraria lobata by ligand fishing based on magnetic mesoporous silicon combined with knock-out/knock-in technology.

In this study, a ligand fishing technique based on magnetic mesoporous silicon was established and used to screen α-glucosidase inhibitors from Pueraria lobata. To clarify quantity-activity relationships in a holistic view, the knock-out/knock-in technology was used to analyse the interactions of several active constituents in P. lobata. Magnetic mesoporous silicon with a large specific surface area and better biocompatibility was synthesised. Subsequently, α-glucosidase was immobilised on -NH2-modified magnetic mesoporous silicon, and the compounds in the crude extract of P. lobata were screened across enzyme binding. The structures of the ligands were elucidated using UPLC-Q-TOF-MS/MS, and their activities were verified by knock-out/knock-in experiments and molecular docking. Daidzein and puerarin showed α-glucosidase inhibitory activities with an IC50 of 0.088 ± 0.003 mg mL-1 and 0.414 ± 0.005 mg mL-1, respectively. Among them, puerarin, which accounted for more than 40% of the total content, showed synergistic effects with other components and was the main contributor to the α-glucosidase inhibitory activity of P. lobata.

Effects of Macrophage Polarization Induced by Mesoporous Silicon-Based Curcumin-siRNA Nanoparticles on the Proliferation of Tendon Stem Cells

Studies have shown that curcumin (CUR)-siRNA can improve excessive fibrosis in the repair of patellar tendon (PT) injury. First, mesoporous silicon nanoparticles (NPs) (MES-SiN) were prepared by a sol–gel method. The small molecule CUR was adsorbed in the internal pore canal of MES-Sin, and the cationic high molecular polyethyleneimine (PP) was adsorbed on the outer layer, which combined with negatively charged siRNA to form CUR@MES-SiN-PP/siRNA NPs. The preparation of NPs was observed by transmission electron microscopy (TEM). RAW264.7 macrophages were treated with different concentrations of NPs, and cell viability was determined by methyl tetrazolium (MTT) assay. The NPs were prepared by siRNA labeled with the fluorescent dye 6-carboxyfluorescein (FAM) and transfected into cells. The cellular uptake of the NPs was observed by confocal laser scanning microscopy (CLSM) and TEM. A total of 80 SPF SD rats (10 weeks of age) were randomly assigned into two groups to establish a PT injury model. The rats in experimental (Exp) group were injected with CUR@MES-SiN-PP/siRNA NP solution (2 μg/g) in the abdomen for 14 d, and those in control (Ctrl) group were injected with an equal dose of 1% dimethyl sulfoxide (DMSO). The rectus femoris of 24 rats were taken from each group 12 h and 1 d, 3 d, 5 d, 7 d, and 14 d after injury. Masson and hematoxylineosin were used to observe the degree of fibrosis of the PT tissue. The differentiation of macrophages was observed by flow cytometry, and the proliferation of tendon stem cells was observed by immunofluorescence approaches such as Pax7. The results suggested that CUR@MES-SiN-PP/siRNA NPs were successfully fabricated. The NPs showed dose-dependent cytotoxicity, the cell viability remained above 90% at concentrations below 10 μg/mL, and the NPs were ingested by higher cells. After injury, the fibrotic area of Exp group was drastically decreased (P <0.05), and the regenerated muscle fiber area was increased (P <0.05). The number of M2-type macrophages increased markedly 3 d, 5 d, 7 d, and 14 d after injury (P <0.05). Immunofluorescence showed that the proliferation of fluorescent cells 3 d after surgery was superior to that of Ctrl group (P <0.05).

Efficient and sustainable preparation of cinnamic acid flavor esters by immobilized lipase microarray

Green and effective synthesis of flavor esters is a long-term interest in food, cosmetic and pharmaceutical industries. Here, an immobilized lipase microarray was prepared by immobilizing lipase CSL on hydrophobically modified ordered mesoporous silicon (CSL@OMS-C8) for the enzymatic production of cinnamic esters with different flavors. The results showed that the CSL@OMS-C8, with an immobilization capacity of 249.3 ± 11.1 mg/g, exhibited 1.6 times higher catalytic activity than that of free lipase at the optimum temperature of 70 °C. The maximum yield of benzyl cinnamate reached 97.3% in 2 h with the corresponding CE value of 650.5 μmol/g · h, leading to the highest record compared to the current literature. Besides, the CSL@OMS-C8 could maintain 81.4 ± 1.1% conversion for cinnamic acid after five-cycle reuse, thus revealing the high stability and reusability of immobilized lipase. Finally, the broad applicability of the immobilized lipase microarray was confirmed by its capacity to successfully catalyze the synthesis of methyl cinnamate, ethyl cinnamate, butyl cinnamate, geranyl cinnamate and isoamyl cinnamate. This study reveals new insights on the efficient and sustainable enzymatic approach to produce natural cinnamic acid flavor esters and, consequently, could pave the way for the natural and clean production in food industries.

Erythrocyte Membrane-Camouflaged Aggregation-Induced Emission Nanoparticles for Fetal Intestinal Maturation Assessment.

Assessment of fetal maturity is essential for timely termination of pregnancy, especially in pregnant women with pregnancy complications. However, there is a lack of methods to assess the maturity of fetal intestinal function. Here, we constructed erythrocyte membrane-camouflaged aggregation-induced emission (AIE) nanoparticles. Nanocore is formed using a hollow mesoporous silicon nanobox (HMSN) of different particle sizes loaded with AIE luminogens -PyTPA (P), which are then co-extruded with erythrocyte membranes (M) to construct M@HMSN@P. The 100 nm M@HMSN@P has a more effective cellular uptake efficiency in vitro and in vivo. Swallowing and intestinal function in fetal mice mature with the increase in gestational age. After intrauterine injection of M@HMSN@P, they were swallowed and absorbed by fetal mice, and their swallowed and absorbed amount was positively correlated with the gestational age with a correlation coefficient of 0.9625. Using the M@HMSN@P (fluorescence intensity) in fetal mice, the gestational age can be imputed, and the difference between this imputed gestational age and the actual gestational age is less than 1 day. Importantly, M@HMSN@P has no side effect on the health status of pregnant and fetal mice, showing good biocompatibility. In conclusion, we constructed M@HMSN@P nanoparticles with different particle sizes and confirmed that the smaller size M@HMSN@P has more efficient absorption efficiency and it can assess fetal intestinal maturity by the intensity of the fluorescence signal.

Preparation of mesoporous carbon with adjustable diameter and pore size

Mesoporous carbon (MC) has attracted extensive scientific and technological interest due to its fascinating and excellent properties. However, it remains a great challenge to synthesize MC materials with adjustable pore diameter and particle size, well-designed functionalities, uniform morphology, relatively high graphitization, and good repeatability. Herein, using mesoporous silicon (SiO2) as a template, we fabricated a locally ordered MC material with controllable pore size by the nanocasting strategy. The carbon material exhibited a large specific surface area (~979 m2/g), relative high graphitization degree, adjustable pore size (2.85–5.79 nm), and particle diameter (79–194 nm). Different experimental conditions were regulated; the organic molecules (cetyltrimethylammonium bromide) played an important role in the change of particle diameter, while the hydrothermal reaction time accurately controlled the pore size. This simple preparation approach simultaneously realized the independent design of the carbon structure and graphitization degree, which is conducive to the subsequent doping modification of carbon materials.

Nanostructures of silicon anodes in Li-ion batteries

As the application scenarios of lithium-ion batteries expand to many fields including electric vehicles and wearable devices, the energy density of current Li-ion batteries should be improved for satisfying the raising demand. In recent years, various methods have been gradually intensified, in which battery anode materials have received widespread attention. One of the most effective ways for improving battery performance is the use of silicon with different nanostructures, such as structures with different dimensions and different elemental doping, as the anode material, which can effectively improve the stability of solid electrolyte layers, enhance the number of reversible cycles and reversible capacity. This review summarizes the latest advances in silicon nanostructured anodes for lithium-ion batteries including nitrogen-doped carbon-caged silicon nanoparticles, silicon nanotubes made of layered CaSiO3, layered porous silicon encapsulated in carbon nanotube cages, silicon nanoparticles encapsulated in carbon-coated mesoporous silicon shells, and three-dimensional hierarchical porous structures. These nanostructures with excellent electrochemical properties can provide directions for the evolution of high-performance lithium-ion batteries.

PH-labile artificial natural killer cells for overcoming tumor drug resistance.

Natural killer (NK) cells exert cytotoxic effects against infected or stressed cells, such as tumor cells, without the limitation of major histocompatibility complex (MHC) I. NK cells secrete perforins to form tunnels to mediate the entry of granzyme into target cells. This strategy, selected by natural evolution, provides a feasible method for the delivery of antitumor drugs against intracellular targets, and avoids drug-resistant mechanisms in tumor cells, such as the pumping out of drugs mediated by multidrug resistance. We constructed pH-labile artificial NK cells (ANKC) based on nature to mediate high levels of drugs in tumor cells to overcome tumor drug resistance. Mesoporous silicon nanoparticles (MSNs) modified with benzaldehyde were designed to function as scaffolds for ANKC. Doxorubicin (Dox), a model antitumor drug, was loaded into the pores of MSNs. Melittin, a pore-forming peptide, was utilized as the gate for mesopores with an acid-labile Schiff base linkage. pH-labile ANKC released melittin and Dox in slightly acidic tumor microenvironments. Melittin, like perforin, assembled tunnels on the plasma membrane or endosome, ensuring the intracellular transportation of Dox. Dox, similar to granzyme, induced the apoptosis of tumor cells. The combinational treatment partially eased the drug resistance mechanism, such as pumping out of drugs, by continuous intracellular drug accumulation mediated by melittin pores. The pH-labile ANKC demonstrated significant Dox enrichment in drug-resistant MCF-7/Adr cells and MCF-7/Adr-based xenograft tumors in a mouse model, which eventually contributed to efficient inhibition of the proliferation and growth of MCF-7/Adr tumors. PH-labile ANKC provided a potential strategy to treat drug-resistant tumors.

Immune-awakening Saccharomyces-inspired nanocarrier for oral target delivery to lymph and tumors.

Utilization of the intestinal lymphatic pathway will allow extraordinary gains in lymph and tumors cascade-targeted delivery of oral drugs and awakening the innate/adaptive immunity of the body and the lesion microenvironment, in addition to improving oral bioavailability relative to other means of delivery of oral drugs. Here, inspired by the specific invasion route of intestinal microorganisms, we pioneered an immune-awakening Saccharomyces-inspired mesoporous silicon nanoparticle (yMSN) for the ingenious cascade-targeted delivery of therapeutic cancer vaccines and antitumor drugs to lymph and tumors via the intestinal lymphatic pathway. Encouragingly, yMSN high-loaded tumor-specific antigens (OVA, 11.9%) and anti-tumor drugs (Len, 28.6%) with high stability, namely Len/OVA/yMSN, efficiently co-delivered OVA and Len to their desired target sites. Moreover, yMSN concomitantly awakened the innate antitumor immunity of dendritic cells and macrophages, strengthening vaccine-induced adaptive immune responses and reversing macrophage-associated immunosuppression in the tumor microenvironment. Surprisingly, Len/OVA/yMSN treatment resulted in excellent synergistic antitumor efficacy and long-term antitumor memory in OVA-Hepa1-6-bearing mice. This high-performance nanocarrier provides a novel approach for lesion-targeting delivery of oral drugs accompanied with awakening of the innate/adaptive immunity of the lesion environment, and also represents a novel path for the oral delivery of diverse therapeutic agents targeting other lymph-mediated diseases.

A bifunctional zoledronate sustained-release system in scaffold: Tumor therapy and bone repair

It is of great challenges to repair bone defect and prevent tumor recurrence in bone tumors postoperative treatment. Bone scaffolds loaded with zoledronate (ZOL) are expected to solve these issues due to its osteogenesis and anti-tumor ability. Furthermore, ZOL needs to be sustained release to meet the requirement of long-term therapy. In this study, ZOL was loaded into amination functionalized mesoporous silicon (SBA15NH2), and then incorporated into poly (L-lactic acid) to prepare PLLA/SBA15NH2-ZOL scaffold via selective laser sintering technology. On one hand, ZOL of local release not only can inhibit growth and proliferation of bone tumor cells but also inhibit osteoclast differentiation through competitive binding of receptor activator of nuclear factor (NF)-kB (RANK) in osteoclast precursors. On the other hand, amination function could change the surface charge of mesoporous silica to positive charge to enhance the absorption of ZOL, mesoporous structure and abundant amino groups of SBA15NH2 play a barrier role and form hydrogen bond with phosphate groups of ZOL, respectively, thereby achieving its sustained release. The results showed that the loading amount of ZOL was 236.53 mg/g, and the scaffold could sustainedly release ZOL for more than 6 weeks. The scaffold inhibited proliferation of osteosarcoma cells through inducing apoptosis and cell cycle arrest. TRAP staining and F-actin ring formation experiment showed the scaffold inhibited differentiation and mature of osteoclast. Pit formation assay indicated that bone resorption activity was inhibited strongly.

Thick pore walls mesoporous silicon composites based on phosphomolybdic acid: An efficient catalyst for oxidation desulfurization reaction

In this paper, phosphomolybdic acid (HPMo) solution was chosen as a synthetic medium and active ingredient to replace hydrochloric acid, and the thick porous wall silicon composite based on HPMo (HPMo@OMS) was prepared by the one-step co-condensation method, which simplified the preparation process and improved the stability of the molecular sieve framework structure. The composite materials have the same ordered 2D hexagonal mesoporous structure as SBA-15. Compared to the traditional SBA-15 loaded HPMo (HPMo@SBA-15) synthesized in hydrochloric acid solution, the characterization results showed that the pore wall thickness of HPMo@OMS is about 2 nm thicker than the HPMo@SBA-15. Under mild experimental conditions, the catalyst has high desulfurization activity, and the removal rate of sulfur-containing substrate reaches 100%. In addition, after 10 desulfurization cycles, the Mo content of the composites recovered by centrifugation 13.74HPMo@OMS was only 1.67% by ICP-AES, the results after ten cycles of experiments showed that the removal rate of DBT could still reach 93.5%.

An ultrasensitive electrochemical immunosensor for carcinoembryonic antigen detection based on two-dimensional PtPd/Cu-TCPP(Fe) nanocomposites.

Establishing an effective signal amplification strategy is the key to achieving sensitive detection of analytes by electrochemical immunoassay. In this work, a novel sandwich-type electrochemical immunosensor with dual-signal amplification was successfully constructed using PtPd/Cu-TCPP(Fe) as the sensing platform and mesoporous silicon dioxide as the signal amplifier. Firstly, two-dimensional wrinkled Cu-TCPP(Fe) nanomaterials loaded with PtPd nanoparticles have strong affinity for the immobilization of capture antibodies and can generate excellent electrochemical signals. Meanwhile, the mesoporous silicon dioxide with large steric hindrance was used as signal label to further improve the sensitivity of the immunosensor by increasing the difference of the current response signal. Under optimal experimental conditions, the electrochemical immunosensor exhibited a wide linear detection range from 0.1pg/mL to 1.0μg/mL, with a detection limit as low as 0.166fg/mL. The experimental results showed that the constructed immunosensor has a great application prospect in clinical biomarker detection.

Digital and Gradient Refractive Index Planar Optics by Nanoimprinting Mesoporous Silicon

AbstractWe report the realization of digital and gradient index flat‐optics and planar waveguides using the ‘nanoimprinting refractive index’ (NIRI) technique applied to mesoporous silicon. This technique combines the distinct optical and mechanical metamaterial qualities of mesoporous silicon, including its widely tunable effective refractive index and ability to undergo plastic deformation with a near zero Poisson ratio. Nanoimprinting with premastered and reusable stamps containing analog or digital features enables the continuous or discontinuous patterning of refractive index with high contrast Δn ≥ 0.8 and subwavelength resolution. Using NIRI we experimentally demonstrate a wavefront shaping flat microlens array operating in the visible (405–635 nm) and mesoporous silicon and silica waveguides operating near 1310 nm. This study demonstrates the viability of patterning arbitrary refractive index distributions, n(x,y), on the surface of a chip while circumventing the challenges and limitations of top‐down lithographic techniques – thus opening a low‐cost and scalable approach for the realization of advanced planar optical technologies.