Hollow mesoporous silica nanoparticles as nanocarriers employed in cancer therapy: A review

Hollow mesoporous silica nanoparticles (HMSNs) have become an attractive drug carrier because of their unique characteristics including stable physicochemical properties, large specific surface area and facile functionalization, especially made into intelligent drug delivery systems (DDSs) for cancer therapy. HMSNs are employed to transport traditional anti-tumor drugs, which can solve the problems of drugs with instability, poor solubility and lack of recognition, etc., while significantly improving the anti-tumor effect. And an unexpected good result will be obtained by combining functional molecules and metal species with HMSNs for cancer diagnosis and treatment. Actually, HMSNs-based DDSs have developed relatively mature in recent years. This review briefly describes how to successfully prepare an ordinary HMSNs-based DDS, as well as its degradation, different stimuli-responses, targets and combination therapy. These versatile intelligent nanoparticles show great potential in clinical aspects.     

介孔分子硅剂改善茶浓缩膜结构特性应用研究

为有效提高功能性茶浓缩反渗透膜的回收效率和抗污性能,探究了3种介孔分子硅材料(MCM-41、SBA-15和MCFs)对浓缩膜面聚酰胺层聚合形成过程的结构影响。结果表明,添加质量分数0.02%经磺化预处理的MCM-41于间苯二胺水相可接枝酰氯基团,形成的聚酰胺结构层峰谷粗糙跨度仅为220 nm且交联紧致,膜抗拉伸强度增加37.8%;SBA-15和MCFs相膜面峰谷跨度达500~780 nm,横向褶皱和团聚,结构存在孔道塌陷;改性膜在3 h内对茶多酚、茶多糖、茶蛋白即可达到最大浓缩度,减少50%浓缩时间;MCM-41和SBA-15膜长时间运行的浓缩降率仅为2.8%~6.1%,48 h下降率比显示改性膜达标使用时长增加112.5%~137.5%,亲水性和抗污堵能力均大幅提升,可有效满足功能化茶浓缩精度。     

A spectroscopic method for quick evaluation of tint strength and tint tone of titania (rutile) pigment and factors affecting them

Titanium dioxide (TiO₂) manufacturing industries measure optical properties such as brightness, colour, tint strength, tint tone, gloss, scatter coefficient, and others to ensure the quality of the product. Product characterization and process control generally focus on the optical properties, which determine its quality. In this work, titania rutile pigment with varying tint strength and tint tone is analyzed and a correlation is established between particle size and the optical properties such as tint strength and tint tone. It is observed that optical properties of titania pigment depends on the particle size as well as particle size distribution. A relatively faster evaluation of tint strength and tint tone can be made using the reflectance and particle size measurements. Analytical samples were prepared by ultrasonic dispersion of pigment in water containing calgon as dispersing agent. To verify the accuracy of the method, pigment tint strength and tint tone obtained from this study are compared with those resulting from traditional analysis. The results showed that the new method is viable.     

Engineering the Structure of Mesoporous Bioactive Glass Microspheres by the Surface Effect of Inverse Opal Templates and Temperature

The interactions of ions and molecules with material surface are highly dependent on the surface properties of the material. Therefore, the distribution of ions or molecules near the material surface may be affected by the surface properties. This phenomenon can be significant enough for controlling the structure of a material synthesized in the sub‐micrometer scale confinement space of a template. This work confirms that inverse opals are perfect templates for offering confinement space, while their different surface properties can strongly affect ion and block copolymer distribution in the confinement space. This surface effect principle can be used for the controlled synthesis of colloids with complex composition. As an example, four kinds of mesoporous magnetic bioactive glass colloids with ordered mesopores, core–shell structure, open surface pores, or disordered mesopores are prepared by using polystyrene and carbon inverse opal templates. This work reveals that inverse opal templates possess great advantage in controlled synthesizing colloidal structures due to their surface effect on ions and molecules and confinement space.     

New kinetic models for the crystallization of anatase nanoparticles from amorphous titania (TiO2)

In this article, amorphous Titania (TiO₂) nanoparticles were crystallized both in a solution environment and by a dry heat treatment using new kinetic models with the capabilities of more accurately predicting the polymorphic transformation behavior of TiO₂. In these models, both the nucleation and growth processes were simultaneously taken into account. The results were indicative of the Surface Nucleation (SN) of anatase occurring in a hydrothermal treatment process through the phase transformation. Also, both the surface and interface nucleation processes were found to play significant roles in the phase transformation kinetics when dealing with dry heat treatments at low temperatures. The proposed models were advantageous to any other published models, in which the nucleation mechanisms had been incorporated with suitable growth expressions. In other words, no experimental data of a particle size were required to investigate the phase transformation kinetics of TiO₂ nanoparticles in the models presented in this article.     

Synthesis and evaluation of several high absorbance black pigments for spacecraft thermal control coatings

Using black coatings and materials with high light absorbance that are capable of absorbing photons at visible and longer wavelengths is a very effective way to reduce unwanted stray light, also known as optical noise, within optical equipment. These lights can be greatly reduced to a reasonable level by functional and performable black coatings that are modified to absorb incident light as much as possible by their specific pigments. In the present work, several carbonaceous pigments were synthesized for the first time from wasteful materials and their optical properties in the visible and near‐infrared ranges studied. First, MCM‐48 and SBA‐15 were synthesized at different conditions and were then used as templates for carbonaceous products. SSS‐1 (the carbonic pigment synthesized by the mixture of sucrose and sodium silicate), SSS‐2 (the carbonic pigment synthesized by the mixture of sawdust and sodium silicate), and mesoporous carbon pigments (CMK‐3 and CMK‐1 with different levels of saturations) were synthesized. Finally, their structure, morphology, and optical properties were investigated by X‐ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE‐SEM), and Diffuse Reflectance Spectroscopy (DRS). The results indicated that the SSS‐1 pigment had a lower reflectance (below 1%) than carbon black (about 2.5%) in the visible region despite it being more cost‐effective than carbon black. The mesoporous pigments showed very high light absorbance in the visible region (about 2.5%). Compared with other black pigments, the CMK‐1 was the blackest synthesized material with a very low reflectance (about 0.05% in visible region), making it an ideal candidate as a super black pigment for reducing unwanted stray light within optical equipment.     

Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H2S Detection

A nanocomposite material based on copper(II) oxide (CuO) and its utilization as a highly selective and stable gas‐responsive electrical switch for hydrogen sulphide (H₂S) detection is presented. The material can be applied as a sensitive layer for H₂S monitoring, e.g., in biogas gas plants. CuO nanoparticles are embedded in a rigid, nanoporous silica (SiO₂) matrix to form an electrical percolating network of low conducting CuO and, upon exposure to H₂S, highly conducting copper(II) sulphide (CuS) particles. By steric hindrance due to the silica pore walls, the structure of the network is maintained even though the reversible reaction of CuO to CuS is accompanied by significant volume expansion. The conducting state of the percolating network can be controlled by a variety of parameters, such as temperature, electrode layout, and network topology of the porous silica matrix. The latter means that this new type of sensing material has a structure‐encoded detection limit for H₂S, which offers new application opportunities. The fabrication process of the mesoporous CuO@SiO₂ composite as well as the sensor design and characteristics are described in detail. In addition, theoretical modeling of the percolation effect by Monte‐Carlo simulations yields deeper insight into the underlying percolation mechanism and the observed response characteristics.