Interfacial Assembly and Applications of Functional Mesoporous Materials

Functional mesoporous materials have gained tremendous attention due to their distinctive properties and potential applications. In recent decades, the self-assembly of micelles and framework precursors into mesostructures on the liquid-solid, liquid-liquid, and gas-liquid interface has been explored in the construction of functional mesoporous materials with diverse compositions, morphologies, mesostructures, and pore sizes. Compared with the one-phase solution synthetic approach, the introduction of a two-phase interface in the synthetic system changes self-assembly behaviors between micelles and framework species, leading to the possibility for the on-demand fabrication of unique mesoporous architectures. In addition, controlling the interfacial tension is critical to manipulate the self-assembly process for precise synthesis. In particular, recent breakthroughs based on the concept of the "monomicelles" assembly mechanism are very promising and interesting for the synthesis of functional mesoporous materials with the precise control. In this review, we highlight the synthetic strategies, principles, and interface engineering at the macroscale, microscale, and nanoscale for oriented interfacial assembly of functional mesoporous materials over the past 10 years. The potential applications in various fields, including adsorption, separation, sensors, catalysis, energy storage, solar cells, and biomedicine, are discussed. Finally, we also propose the remaining challenges, possible directions, and opportunities in this field for the future outlook.

Dendritic Mesoporous Nanoparticles: Structure, Synthesis and Properties

Recently, a new family of "dendritic" mesoporous silica nanoparticles has attracted great interest with widespread applications. Despite a large number of publications (>800), the terminology of "dendritic" is ambiguous. Understanding what possible "dendritic structures" are, their formation mechanisms and the underlying structure-property relationship is fundamentally important. With the advance of characterization techniques such as electron tomography, two types of tree branch-like and flower-like structures can be distinguished, both described as "dendritic" in literature. In this review, we start with the definition of "dendritic", then provide critical analysis of reported dendritic silica nanoparticles according to their structural classification. We also update the understandings of the formation mechanisms of two types of "dendritic" nanoparticles, with a focus on how to control different structural parameters. Various applications of dendritic mesoporous nanoparticles are also reviewed with a focus in biomedical field, providing new insights into the structure-property relationship in this family of nanomaterials.

Rational Design of Dendritic Mesoporous Silica Nanoparticles' Surface Chemistry for Quantum Dot Enrichment and an Ultrasensitive Lateral Flow Immunoassay

Lateral flow immunoassays (LFIAs) have drawn much attention in point-of-care diagnostic applications, and the development of high-performance label materials is the key. In this study, the impact of the surface chemistry of dendritic mesoporous silica nanoparticles (DMSNs) on their enrichment performance toward quantum dots (QDs) and signal amplification of the resultant DMSNs-QDs as label materials have been investigated. A series of DMSNs with controllable amino/thiol group densities have been synthesized. It is demonstrated that the amino groups are beneficial for QD fluorescence preservation, owing to the amino-based surface passivation, while the thiol groups are responsible for increasing the loading capacity of QDs due to the thiol-metal coordination. The optimized DMSNs-QDs labels with an amino density of 153 μmol g^-1 and a thiol density of 218 μmol g^-1 displayed sufficient QD fluorescence preservation (89.4%) and high QD loading capacity (1.55 g g^-1). Ultrasensitive detection of serum amyloid A (SAA) with a detection limit of 10 pg mL^-1 with the naked eye was achieved, which is 1 order of magnitude higher than that reported in the literature. This study provides insights into the development of advanced label materials and an ultrasensitive LFIA for future bioassay applications.

Intracellular delivery of a native functional protein using cell-penetrating peptide functionalized cubic MSNs with ultra-large mesopores

Pore-enlarged 3D cubic cMSNs were successfully prepared, and their surfaces were functionalized by a cell-penetrating R8-peptide through the click reaction for cytosolic delivery of a functional protein in its native form.

Versatile design and synthesis of nano-barcodes

This review provides a critical discussion on the versatile designing and usage of nano-barcodes for various existing and emerging applications.

Meta-analysis of cellular toxicity for cadmium-containing quantum dots

Understanding the relationships between the physicochemical properties of engineered nanomaterials and their toxicity is critical for environmental and health risk analysis. However, this task is confounded by material diversity, heterogeneity of published data and limited sampling within individual studies. Here, we present an approach for analysing and extracting pertinent knowledge from published studies focusing on the cellular toxicity of cadmium-containing semiconductor quantum dots. From 307 publications, we obtain 1,741 cell viability-related data samples, each with 24 qualitative and quantitative attributes describing the material properties and experimental conditions. Using random forest regression models to analyse the data, we show that toxicity is closely correlated with quantum dot surface properties (including shell, ligand and surface modifications), diameter, assay type and exposure time. Our approach of integrating quantitative and categorical data provides a roadmap for interrogating the wide-ranging toxicity data in the literature and suggests that meta-analysis can help develop methods for predicting the toxicity of engineered nanomaterials.

Hierarchical mesoporous silica nanoparticles as superb light scattering materials

A novel approach to enhance the light scattering effect was explored by applying hierarchical mesoporous silica nanoparticles with a radial wrinkle structure (WSNs) in DSSCs as scattering layers. The WSNs were evaluated as outstanding light scattering materials providing large surface area as well as multiple scattering.

Multifunctional nanocarriers for simultaneous encapsulation of hydrophobic and hydrophilic drugs in cancer treatment

Combination therapy for cancer patients is an important standard of care protocol because it can elicit synergistic therapeutic effects and reduce systemic toxicity by simultaneously modulating multiple cell-signaling pathways and overcoming multidrug resistance. Nanocarriers are expected to play a major role in delivering multiple drugs to tumor tissues by overcoming biological barriers. However, especially considering the different physical chemistry of chemotherapeutic drugs, it is highly desirable to develop a codelivery nanocarrier for controlled and targeted delivery of both hydrophobic and hydrophilic drugs. This review reports the recent developments in various combinational drug delivery systems and the simultaneous use of combinational drug delivery systems with functional agents.

Dendritic silica particles with center-radial pore channels: promising platforms for catalysis and biomedical applications

Dendritic silica micro-/nanoparticles with center-radial pore structures, a kind of newly created porous material, have attracted considerable attention owing to their unique open three-dimensional dendritic superstructures with large pore channels and highly accessible internal surface areas compared with conventional mesoporous silica nanoparticles (MSNs). They are very promising platforms for a variety of applications in catalysis and nanomedicine. In this review, their unique structural characteristics and properties are first analyzed, then novel and interesting synthesis methods associated with the possible formation mechanisms are summarized to provide material scientists some inspiration for the preparation of this kind of dendritic particles. Subsequently, a few examples of interesting applications are presented, mainly in catalysis, biomedicine, and other important fields such as for sacrificial templates and functional coatings. The review is concluded with an outlook on the prospects and challenges in terms of their controlled synthesis and potential applications.