Lysosomal "TRAP": a neotype modality for clearance of viruses and variants.

The binding of viruses to host-entry factor receptors is an essential step for viral infection. Many studies have shown that macrophages can internalize viruses and degrade them in lysosomes for clearance in vivo. Inspired by these natural behaviors and using SARS-CoV-2 as a testbed, we harvest lysosomes from activated macrophages and anchor the protein-receptor ACE2 as bait, thus constructing a lysosomal "TRAP" (lysoTRAP) that selectively captures, internalizes, and eventually degrades SARS-CoV-2.

Understanding Flexdispersion: Structure-Function Relationship Studies of Organic Amphiphilic Ligands.

Since inorganic nanoparticles have unique properties that differ from those of bulk materials, their material applications have attracted attention in various fields. In order to utilize inorganic nanoparticles for functional materials, they must be dispersed without agglomeration. Therefore, the surfaces of inorganic nanoparticles are typically modified with organic ligands to improve their dispersibility.

Merger of Rotation Restriction and Symmetrical Push-Pull to Synthesize Single-Benzene Yellow Fluorophors.

Invited for the cover of this issue is the group of Yohei Okada at Tokyo University of Agriculture and Technology. The image depicts a series of single-benzene fluorophores. Constructing symmetrical push-pull motifs in combination with restricting bond rotations is the key to creating small yet brightly emitting fluorophores.

Merger of Rotation Restriction and Symmetrical Push-Pull to Synthesize Single-Benzene Yellow Fluorophores.

Small yet brightly emitting fluorophores should find fundamental and practical applications in both academic and industrial settings. In this report, tetrahydrobenzodifuran is used as the core architecture to create novel single-benzene fluorophores. The key for realizing unique and powerful photophysical properties is the combination of the construction of symmetrical push-pull motifs and the restriction of bond rotations to suppress molecular motions that cause non-radiative transitions.

Dispersibility of TiO Nanoparticles in Less Polar Solvents: Role of Ligand Tail Structures.

Nanoparticles (NPs) are inherently prone to aggregation and loss of their size-derived properties, thus it is essential to enhance their dispersibility for applications. In less polar solvents, organic ligands containing oleyl groups are known as good dispersants due to their inefficient shell packing and inhibition of chain-chain crystallization as well as interdigitation between adjacent NPs. However, reagents with oleyl structures, such as oleic acid and oleylamine, can contain trans double bonds and saturated impurities, which might affect the chemical and/or physical properties of the NPs.

Radical cation Diels-Alder reactions of arylidene cycloalkanes.

TiO photoelectrochemical and electrochemical radical cation Diels-Alder reactions of arylidene cycloalkanes are described, leading to the construction of spiro ring systems. Although the mechanism remains an open question, arylidene cyclobutanes are found to be much more effective in the reaction than other cycloalkanes. Since the reaction is completed with a substoichiometric amount of electricity, a radical cation chain pathway is likely to be involved.

Colloidal Stability of TiO Nanoparticles: The Roles of Phosphonate Ligand Length and Solution Temperature.

Invited for the cover of this issue are Dr. Shohei Yamashita, Tatsuya Sudo, Prof. Dr.

Design of a Photocatalytic [2+2] Cycloaddition Reaction Using Redox-Tag Strategy.

The design of photocatalytic processes is important for a sustainable society. Key to these photocatalytic reactions is electron transfer. This article is focused on titanium dioxide photocatalyzed organic synthesis and the design of a new [2+2] cycloaddition reaction based on the electron transfer process.

Colloidal Stability of TiO Nanoparticles: The Roles of Phosphonate Ligand Length and Solution Temperature.

Surface ligands are essential tools for the stabilization of colloidal nanoparticles (NPs) in solvents. However, knowledge regarding the effects of the ligand shell, especially the ligand length, is insufficient and controversial. Here we demonstrate solution-based experiments on n-alkylphosphonate-capped TiO NPs to investigate the effects of ligand length and solution temperature on colloidal stability.

Radical-Cation Vinylcyclopropane Rearrangements by TiO Photocatalysis.

Radical cation vinylcyclopropane rearrangements by TiO photocatalysis in lithium perchlorate/nitromethane solution are described. The reactions are triggered by oxidative single electron transfer, which is followed by immediate ring-opening of the cyclopropanes to generate distonic radical cations as unique reactive intermediates. This approach can also be applied to vinylcyclobutane, leading to the construction of six-membered rings.

Probing Intramolecular Electron Transfer in Redox Tag Processes.

Herein, we show that redox tag-guided intermolecular formal [2 + 2] cycloaddition can be used as a probe to investigate intramolecular single-electron transfer (SET) mechanisms. The efficacy of intramolecular SET can be evaluated in association with concomitant carbon-carbon bond formation and/or cleavage, leading to cycloaddition or cross-metathesis. Experimental and theoretical results suggest that the intramolecular SET is under both thermodynamic and kinetic control and can also occur through bonds, not only through space.

Sulfur-free Surfactant for Carbide Nanoparticle Characterization in Steel Using Asymmetric Flow Field-Flow Fractionation Hyphenated Inductively Coupled Plasma-Mass Spectrometry.

An asymmetric flow field-flow fractionation (AF4) combined with inductively coupled plasma mass spectrometry (ICP-MS) was applied to measure the concentration and size distribution of nanometer-sized carbides in steel sheets, such as titanium carbides (TiC) and vanadium carbides (VC). Prior to AF4-ICP-MS measurement, TiC and VC nanoparticles in steel were extracted into a solution via selective potentio-static etching by electrolytic dissolution (SPEED) method. The SPEED method enabled the selective dissolution of iron and the carbide nanoparticles were dispersed as primary particles in solution with surfactant.

Radical Cation Diels-Alder Reactions by TiO Photocatalysis.

Radical cation Diels-Alder reactions by titanium dioxide (TiO) photocatalysis in lithium perchlorate/nitromethane solution are described. TiO photocatalysis promotes reactions between electron-rich dienes and dienophiles, which would otherwise be difficult to accomplish due to electronic mismatching. The reactions are triggered by hole oxidation of the dienophile and are completed by the excited electron reduction of the radical cation intermediate at the dispersed surface in the absence of any sacrificial substrate.

[Characterization of Surface Interaction between Chitosan-modified Liposomes and Mucin Layer by Using CNT Probe AFM Method].

　In order to characterize the adhesion and deformation behavior between chitosan-modified liposomes and the mucin layer of the small intestine, mucin was coated on hydrophobic surface-modified carbon nanotube (CNT) probe of an atomic force microscope. The interaction between this mucin layer and the liposomes with or without chitosan modification in phosphoric acid buffer solution was determined by atomic force microscopy. The pH of the buffer solution was controlled at 2.

Direct Monitoring of Molecular Events at the Surface: One-Step Access to Flexibly Stable Colloidal Ag Nanoparticles.

Design, control, and direct characterization of surface properties are prerequisites to all the practical applications of nanoparticles. Since stable and homogeneous colloidal conditions are required for most applications, the amenability of nanoparticles to in-solution processing must also be addressed. Herein, we demonstrate that solution H NMR spectroscopy is an effective tool for direct monitoring of the production of Ag nanoparticles.

TiO Photocatalysis in Aromatic "Redox Tag"-Guided Intermolecular Formal [2 + 2] Cycloadditions.

Since the pioneering work by Macmillan, Yoon, and Stephenson, homogeneous photoredox catalysis has occupied a central place in new reaction development in the field of organic chemistry. While heterogeneous semiconductor photocatalysis has also been studied extensively, it has generally been recognized as a redox option in inorganic chemistry where such "photocatalysis" is most often used to catalyze carbon-carbon bond cleavage and not in organic chemistry where bond formation is usually the focal point. Herein, we demonstrate that titanium dioxide photocatalysis is a powerful redox option to construct carbon-carbon bonds by using intermolecular formal [2 + 2] cycloadditions as models.

Understanding the Colloidal Stability of Nanoparticle-Ligand Complexes: Design, Synthesis, and Structure-Function Relationship Studies of Amphiphilic Small-Molecule Ligands.

For effective application of nanoparticles, their amenability to in-solution processing must be addressed, and stable, homogeneous solvent conditions are required. Although organic ligands have been used as surface-modifying reagents for nanoparticles to increase their colloidal stability and homogeneity in solution, the structure-function relationships of nanoparticle-ligand complexes remain elusive and controversial. Herein, a series of novel amphiphilic small-molecule ligands were designed, synthesized, and applied as surface-modifying reagents for aqueous, transparent TiO and ZrO nanoparticles.

[Relationship between Hydrogen-bond Conditions of Surface Adsorbed Water and Interparticle Binding Force on Pharmaceutical Tablets].

Influence of water contents to the pharmaceutical tablet strength is known empirically, and participation of hydrogen bonding force among adsorbed water molecules has been presumed. However, the detailed mechanisms of hydrogen bonding phenomena have not been reported. In this study, the hydrogen bonds states of the surface adsorbed waters on the excipient particles of the tablets were focused upon, and the relationship to the interparticle binding force determined by the Rumpf equation was discussed using a near-infrared spectroscopy (NIR).

Hydrophobic benzyl amines as supports for liquid-phase C-terminal amidated peptide synthesis: application to the preparation of ABT-510.

C-terminal amidation is one of the most common modification of peptides and frequently found in bioactive peptides. However, the C-terminal modification must be creative, because current chemical synthetic techniques of peptides are dominated by the use of C-terminal protecting supports. Therefore, it must be carried out after the removal of such supports, complicating reaction work-up and product isolation.

Multi-scale modelling of powder dispersion in a carrier-based inhalation system.

Purpose: Carrier-based dry powder inhalers (DPIs) are widely used for rapid and convenient delivery of drug to the site of action. This work aimed to predict powder aerosolisation in DPIs through numerical modelling.

Methods: A multi-scale modelling technique based on the combined computational fluid dynamics (CFD) and discrete element method (DEM) approach was developed.

Toward continuous LC-MS analysis: surface modification of magnetic microparticles with TiO2 for phosphate adsorption.

Continuous liquid chromatography-mass spectrometry (LC-MS) analysis was successfully demonstrated by using magnetic TiO2/Fe3O4 microparticles at the desalination interface. The particles could be prepared easily even on a practical scale at sufficient quality for efficient phosphate adsorption. Not only phosphate but several biomolecules were adsorbed onto the particles in a non-specific manner.

Layer-by-layer surface modification of functional nanoparticles for dispersion in organic solvents.

In order to prepare SiO(2) nanoparticles that are dispersible in various organic solvents, an anionic surfactant 1, which branches into a hydrophobic chain and a hydrophilic chain, was adsorbed on to SiO(2) nanoparticles through a layer-by-layer surface modification route using polyethyleneimine (PEI). First, the relationship among the additive content of PEI, adsorbed content of PEI, and the redispersion stability of the SiO(2) nanoparticles in water was investigated. While almost the entire PEI was adsorbed when the additive PEI content was lower than 67 mg/g of SiO(2), the adsorbed content of PEI became saturated when the additive content was increased above 90 mg/g of SiO(2).

Surface modification and characterization for dispersion stability of inorganic nanometer-scaled particles in liquid media.

Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids.

Anionic surfactant with hydrophobic and hydrophilic chains for nanoparticle dispersion and shape memory polymer nanocomposites.

An anionic surfactant comprising a hydrophilic poly(ethylene glycol) (PEG) chain, hydrophobic alkyl chain, and polymerizable vinyl group was synthesized as a capping agent of nanoparticles. TiO(2) nanoparticles modified by this surfactant were completely dispersible in various organic solvents with a wide range of polarities, such as nitriles, alcohols, ketones, and acetates. Furthermore, these particles were found to be dispersible in various polymers with different properties, such as thermosetting epoxy resins and radical polymerized poly(methylmethacrylate) (PMMA).

Rapid magnetic catch-and-release purification by hydrophobic interactions.

A reversible, conventional, and rapid purification method of hydrophobically tagged products using hydrophobic magnetic nanoparticles was developed. The reversible purification system entails simply controlling the polarity of solvents. First, for the catching procedure, poor solvents were added into a well-dispersed system of magnetic nanoparticles and tagged products.