Adsorptive removal of lead from aqueous solutions by amine–functionalized magMCM-41 as a low–cost nanocomposite prepared from rice husk: Modeling and optimization by response surface methodology

Amorphous silica that was extracted from rice husk was used to synthesize the magMCM-41 mesoporous silica. This was then functionalized by the APTMS group in order to produce NH₂-magMCM-41 as a novel and low–cost adsorbent. The XRD, VSM, N₂ adsorption–desorption, FT–IR, TGA, SEM and TEM analyses were utilized to characterize the produced materials. In order to optimize the adsorption of the Pb(II) ions, the RSM (response surface methodology) was applied by using the synthesized adsorbent in aqueous solutions. A rotatable CCD (central composite design) was adopted to carry out the experiments and RSM was used to analyze them. Three independent factors namely, initial solution pH (3–7), adsorbent dosage (0.1–2 g L^?1), and initial Pb(II) concentration (15–150 mg L^?1) were used to investigate the removal procedure. According to the obtained results, the initial solution pH of 5.22, adsorbent dosage of 0.1 g L^?1, and initial Pb(II) concentration of 150 mg L^?1 were considered as the optimum conditions with 64.32% removal of Pb(II) and an adsorption capacity of 540.64 mg g^?1. The maximum removal efficiency of Pb(II) ions was found to be 96.76%. The Sips isotherm model represents a better correlation with equilibrium data. It was reported by the kinetic study that data taken from the experiments fitted better to the pseudo–second–order model compared to the pseudo–first–order and intraparticle diffusion models. Finally, according to the thermodynamic study, the removal process strongly depends on temperature, which indicates an exothermic behavior and spontaneous nature of the adsorption.     

Spherical V-Fe-MCM-48: The Synthesis,Characterization and Hydrothermal Stability

Spherical MCM-48 mesoporous sieve co-doped with vanadium and iron was successfully synthesized via one-step hydrothermal method. The material was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, inductively coupled plasma (ICP), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-vis spectra, and X-ray photoelectron spectra (XPS) techniques. Results indicated that the V-Fe-MCM-48 showed an ordered 3D cubic mesostructure with spherical morphology, narrow pore size distribution and high specific surface area. Most of vanadium and iron atoms existing as tetrahedral V⁴⁺ and Fe³⁺ species were co-doped into the silicate framework. The particle sizes of V-Fe-MCM-48 were smaller and the specific area was much higher than those of of V-MCM-48. Additionally, the synthesized V-Fe-MCM-48 exhibited improved hydrothermal stability compared with the pure MCM-48.     

Facile Synthesis of Core–shell Magnetic Mesoporous Silica Nanoparticles for pH‐sensitive Anticancer Drug Delivery

The facile synthesis of core–shell magnetic mesoporous silica nanoparticles (Fe₃O₄@mSiO₂ NPs) was reported in aqueous phase using cetyltrimethylammonium bromide as a template under alcohol‐free conditions. Compared to the conventional synthesis method for core–shell Fe₃O₄@mSiO₂ NPs, the approach in this study is rapid (only 5‐min reaction time), cheap (without using organic agents), and environmentally friendly (one‐step synthesis in alcohol‐free medium). Doxorubicin (DOX)‐loaded Fe₃O₄@mSiO₂ NPs exert extraordinarily high specificity for liver cancer cells, which was due to the pH‐sensitive doxorubicin release, as well as higher endocytosis capacity in liver cancer cells rather than normal liver cells. The potential advantages of using such Fe₃O₄@mSiO₂ NPs as the vehicle of anticancer drugs were that the Fe₃O₄@mSiO₂ NPs exhibit good biocompatibility, high loading and protection of the guest molecules, selective killing effect, and efficient cellular uptake. The exciting pH‐dependent release properties of doxorubicin‐loaded Fe₃O₄@mSiO₂ NPs make their use a promising strategy for enhancing efficient therapy toward tumors, while reducing the cytotoxicity of doxorubicin to human normal neutral tissue or cells.     

壳聚糖修饰的载穿心莲内酯介孔二氧化硅纳米粒的制备及其pH响应性释药性能考察

目的:制备壳聚糖修饰的载穿心莲内酯介孔二氧化硅纳米粒(CS/Ap-MSN),对其进行体外质量评价及p H响应性释药性能考察。方法:根据改良经典stober法一步合成了氨基修饰的介孔二氧化硅纳米粒(NH2-MSN),利用壳聚糖进行偶联修饰,表征其形貌及结构,通过体外释放试验考察CS/Ap-MSN在不同p H条件下的响应性释药性能。结果:CS/Ap-MSN的平均粒径(178.0±3.2)nm,多分散指数0.378±0.117,Zeta电位(34.04±0.22)mV,载药量和包封率分别为(27.8±1.7)%,(63.6±3.2)%,壳聚糖的修饰量6.3%。CS/Ap-MSN在p H 5.0的释放条件下,8 d累计释药量达53.3%;pH 7.4的释放条件下,8 d的累计释药量23.4%。结论:CS/Ap-MSN的体外释药具有p H响应性,累积释放量随p H减小而增大,且具有一定的缓释性能。     

介孔二氧化硅纳米粒增溶型非诺贝特片剂的制备及体内外研究

目的 制备介孔二氧化硅纳米粒(mesoporous silica nanoparticles,HK)增溶型非诺贝特(fenofibrate,FNB)片剂并进行体内外研究。方法 用吸附法以HK为FNB的载体制成固体分散体(FNB-HK)。采用差示扫描量热法、X射线衍射法和傅里叶红外光谱法分析非诺贝特在FNB-HK中的存在状态。通过考察体外溶出度,优化处方并制片。将自制片和市售片分别对家兔单剂量口服给药,采用高效液相色谱法测定家兔血浆药物浓度。结果 FNB-HK表征表明HK能够抑制非诺贝特的结晶。经过处方优化,乳糖做填充剂,8%羧甲基淀粉钠为崩解剂时,片剂能够达到最理想的溶出速率。自制片与市售片相比,体内达峰时间提前,达峰浓度增大,相对生物利用度为149.95%。结论 本研究研制的片剂能显著改善FNB的溶出速率,提高其口服生物利用度。     

In Vitro and In Vivo Evaluation of Core–Shell Mesoporous Silica as a Promising Water-Insoluble Drug Delivery System: Improving the Dissolution Rate and Bioavailability of Celecoxib With Needle-Like Crystallinity

The objective of our study was to prepare mesoporous silica nanoparticles with a core–shell structure (CSMSNs) and improve the dissolution and bioavailability of celecoxib (Cxb), a water-insoluble drug, by changing its needle-like crystal form. CSMSNs are prepared by a core-shell segmentation self-assembly method. The S_BET and V_t of CSMSNs were 890.65 m²/g and 1.23 cm³/g, respectively. Cxb was incorporated into CSMSNs by the solvent evaporation method. The gastrointestinal irritancy of the CSMSNs was evaluated by a gastric mucosa irritation test. In vitro dissolution and in vivo pharmacokinetic tests were carried out to study the improvement in the dissolution behavior and oral bioavailability of Cxb. In conclusion, gastric mucosa irritation study indicated the good biocompatibility of CSMSNs. The cumulative dissolution of CSMSNs-Cxb is 86.2% within 60 min in SIF solution, which may be ascribed to the crystal form change caused by control of the nanochannel for CSMSNs. Moreover, CSMSNs could enhance the 9.9-fold AUC of Cxb. The cumulative dissolution and bioavailability of Cxb were both significantly enhanced by CSMSNs. CSMSNs with a core–shell structure are suitable as a carrier for a poorly water-soluble drug (Cxb).     

Simple Preparation of Novel Metal-Containing Mesoporous Starches

Metal-containing mesoporous starches have been synthesized using a simple and efficient microwave-assisted methodology followed by metal impregnation in the porous gel network. Final materials exhibited surface areas >60 m² g⁻¹, being essentially mesoporous with pore sizes in the 10–15 nm range with some developed inter-particular mesoporosity. These materials characterized by several techniques including XRD, SEM, TG/DTA and DRIFTs may find promising catalytic applications due to the presence of (hydr)oxides in their composition.     

Phosphorus Effects of Mesoporous Bioactive Glass on Occlude Exposed Dentin

In recent studies, sealing of exposed dentinal tubules is generally considered as one of the most effective strategies to treat dentin hypersensitivity. Mesoporous bioactive glass (MBG) is a potential material for treating dentin hypersensitivity due to its highly specific areas for dissolution and re-precipitated reaction for reduction in dentin permeability. The groups of commercial products of PerioGlas^®, synthetic MBG and MBG without phosphorus (MBGNP) were compared. The MBG and MBGNP powders were prepared by the sol-gel method and mixed with different calculated ratios of phosphoric acid (PA) and then was brushed onto dentin surfaces. We used X-ray diffractometer (XRD), scanning electronic microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) to investigate the physiochemistry and the occlusion ability of dentinal tubules. The results showed that MBG paste mixed with PA solution has a better ability for occluding dentinal tubules than MBGNP; it has a short reaction time and good operability. The major crystallite phase of MBG agents was monocalcium phosphate monohydrate [Ca(H₂PO₄)₂·H₂O] in the early stages of the reactions. MBG pastes that were mixed with 30% and 40% PA had the ability to create excellent penetration depth greater than 80 μm. These agents have the potential to treat dentin hypersensitivity.     

Packaging biological cargoes in mesoporous materials: opportunities for drug delivery

Introduction: Confinement of biomolecules in structured nanoporous materials offers several desirable features ranging from chemical and thermal stability, to resistance to degradation from the external environment. A new generation of mesoporous materials presents exciting new possibilities for the formulation and controlled release of biological agents. Such materials address niche applications in enteral and parenteral delivery of biologics, such as peptides, polypeptides, enzymes and proteins for use as therapeutics, imaging agents, biosensors, and adjuvants.

Areas covered: Mesoporous silica Santa Barbara Amorphous-15 (SBA-15), with its unique, tunable pore diameter, and easily functionalized surface, provides a representative example of this new generation of materials. Here, we review recent advances in the design and synthesis of nanostructured mesoporous materials, focusing on SBA-15, and highlight opportunities for the delivery of biological agents to various organ and tissue compartments.

Expert opinion: The SBA-15 platform provides a delivery carrier that is inherently separated from the active biologic due to distinct intra and extra-particle environments. This permits the SBA-15 platform to not require direct modification of the active biological therapeutic. Additionally, this makes the platform universal and allows for its application independent of the desired methods of discovery and development. The SBA-15 platform also directly addresses issues of targeted delivery and controlled release, although future challenges in the implementation of this platform reside in particle design, biocompatibility, and the tunability of the internal and external material properties. Examples illustrating the flexibility in the application of the SBA-15 platform are also discussed.     

多功能介孔二氧化硅纳米粒在肿瘤治疗中的研究进展

介孔二氧化硅纳米粒由于较高的物理化学稳定性、易于官能化、低毒性以及对许多不同类型治疗剂的巨大负载能力,涉及了化学药物治疗、光热治疗、光动力治疗以及联合治疗,在肿瘤治疗方面受到极大的关注和广泛的研究探索。本文介绍了近年来基于介孔二氧化硅纳米粒作为载体在肿瘤治疗方面的一些研究报道,这些智能化的多功能性已经促使介孔二氧化硅纳米粒成为将来用于临床的非常有前途的药物纳米载体。