A Far-Red Molecular Rotor Fluorogenic Trehalose Probe for Live Mycobacteria Detection and Drug-Susceptibility Testing

Increasing the speed, specificity, sensitivity, and accessibility of mycobacteria detection tools are important challenges for tuberculosis (TB) research and diagnosis. In this regard, previously reported fluorogenic trehalose analogues have shown potential, but their green-emitting dyes may limit sensitivity and applications in complex settings. Here, we describe a trehalose-based fluorogenic probe featuring a molecular rotor turn-on fluorophore with bright far-red emission (RMR-Tre). RMR-Tre, which exploits the unique biosynthetic enzymes and environment of the mycobacterial outer membrane to achieve fluorescence activation, enables fast, no-wash, low-background fluorescence detection of live mycobacteria. Aided by the red-shifted molecular rotor fluorophore, RMR-Tre exhibited up to a 100-fold enhancement in M. tuberculosis labeling compared to existing fluorogenic trehalose probes. We show that RMR-Tre reports on M. tuberculosis drug resistance in a facile assay, demonstrating its potential as a TB diagnostic tool.     

High-Throughput Diversification of Complex Bioactive Molecules by Accelerated Synthesis in Microdroplets

Late-stage diversification of drug molecules is an important strategy in drug discovery that can be facilitated by reaction screening using high-throughput experimentation. Here we present a rapid method for functionalizing bioactive molecules based on accelerated reactions in microdroplets. Reaction mixtures are nebulized at throughputs better than 1 reaction/second and the accelerated reactions occurring in the microdroplets are followed by desorption electrospray ionization mass spectrometry (DESI-MS). Because the accelerated reactions occur on the millisecond timescale, they allow an overall screening throughput of 1 Hz working at the low nanogram scale. Using this approach, an opioid agonist (PZM21) and an antagonist (naloxone) were diversified using three reactions important in medicinal chemistry: sulfur fluoride exchange (SuFEx) click reactions, imine formation reactions, and ene-type click reactions. Some 269 functionalized analogs of naloxone and PZM21 were generated and characterized by tandem mass spectrometry (MS/MS) after screening over 500 reactions.     

An Inorganic Click Reaction for the Synthesis of Interlocked Molecules

We describe the use of the cyaphide-azide 1,3-dipolar cycloaddition reaction for the synthesis of a new class of inorganic rotaxanes containing gold(I) triazaphosphole stoppers. Electron-deficient bis-azides, which thread perethylated pillar[5]arene in aromatic solvents, readily react with two equivalents of Au(IDipp)(CP) (IDipp=1,3-bis-(2,6-diisopropylphenyl)-imidazol-2-ylidene) to afford interlocked molecules via an inorganic click reaction. These transformations proceed in good yields (ca. 65 %) and in the absence of a catalyst. The resulting organometallic rotaxanes are air- and moisture-stable and can be purified by column chromatography under aerobic conditions. The targeted rotaxanes were characterized by multi-element nuclear magnetic resonance (NMR) spectroscopy, mass-spectrometry, and single-crystal X-ray diffraction.     

Permeation devices for the preparation of standard gaseous mixtures

Summary Two new permeation devices for generation of standard gaseous mixtures in wide concentration range have been designer. Teflon membranes and tubing have been utilized as the permeation barriers. The devices enable generation of multi-component mixtures.     

Reliability of Click Chemistry on Drug Discovery: A Personal Account

The unprecedented efficiency, reliability and adaptability in drug discovery, with the growing number of applications and impact, have made Click Chemistry fascinating to the scientific community. The specificity, biocompatibility along with other principles of click chemistry offers a reliable platform for the synthesis of drug‐like molecules that can expedite the drug discovery process. This account summarizes such successes of versatile click reactions from our research group towards the development of functional molecules.     

Bioorthogonal Chemical Reporters for Selective In Situ Probing of Mycomembrane Components in Mycobacteria

The global pathogen Mycobacterium tuberculosis and other species in the suborder Corynebacterineae possess a distinctive outer membrane called the mycomembrane (MM). The MM is composed of mycolic acids, which are either covalently linked to an underlying arabinogalactan layer or incorporated into trehalose glycolipids that associate with the MM non‐covalently. These structures are generated through a process called mycolylation, which is central to mycobacterial physiology and pathogenesis and is an important target for tuberculosis drug development. Current approaches to investigating mycolylation rely on arduous analytical methods that occur outside the context of a whole cell. Herein, we describe mycobacteria‐specific chemical reporters that can selectively probe either covalent arabinogalactan mycolates or non‐covalent trehalose mycolates in live mycobacteria. These probes, in conjunction with bioorthogonal chemistry, enable selective in situ detection of the major MM components.     

化学与社会文理渗透型课程建设的实践与思考

在碳金融为首的化学与经济相结合的时代背景下,经济与管理专业的学生必须具备足够的化学知识以应对未来的挑战,化学的思维方式对经济与管理专业学生在研究问题时意义重大。在分析经济与管理专业生源差异的基础上,作者提出了从课程目标、教学内容以及教学方式上进行文理渗透型的化学与社会课程建设的方法。进一步提出了将传统的化学与社会课程与MOOC进行有机结合,使化学学习更加生趣和灵活化。     

Crystalline Nanoparticles of Water-Soluble Covalent Basket Cages (CBCs) for Encapsulation of Anticancer Drugs

We herein describe the preparation, assembly, recognition characteristics, and biocompatibility of novel covalent basket cage CBC- 11 , composed of four molecular baskets linked to four trivalent aromatic amines through amide groups. The cage is tetrahedral in shape and similar in size to small proteins (M_w=8637 g/mol) with a spacious nonpolar interior for accommodating multiple guests. While 24 carboxylates at the outer surface of CBC- 11 render it soluble in aqueous phosphate buffer (PBS) at pH=7.0, the amphiphilic nature prompts its assembly into nanoparticles (d=250 nm, DLS). Cryo-TEM examination of nanoparticles revealed their crystalline nature with wafer-like shapes and hexagonally arranged cages. Nanoparticulate CBC- 11 traps anticancer drugs irinotecan and doxorubicin, with each cage binding up to four drug molecules in a non-cooperative manner. The inclusion complexation resulted in nanoparticles growing in size and precipitating. In media containing mammalian cells (HCT 116, human colon carcinoma), the IC₅₀ value of CBC- 11 was above 100 μM. While this work presents the first example of a large covalent organic cage operating in water at the physiological pH and forming crystalline nanoparticles, it also demonstrates its biocompatibility and potential to act as a polyvalent binder of drugs for their sequestration or delivery.     

A Simple Method for Estimating the Solubility Parameter of Small Molecules and Polymeric Materials

Russian Journal of Applied Chemistry - The study relates to the problem of selecting a solvent for organic polymers during their chemical processing. Based on the method of Askadsky, simple schemes...     

Structurally Simple Osmium(II) Polypyridyl Complexes as Photosensitizers for Photodynamic Therapy in the Near Infrared**

Five osmium(II) polypyridyl complexes of the general formula [Os(4,7-diphenyl-1,10-phenanthroline)₂ L ]²⁺ were synthesized as photosensitizers for photodynamic therapy by varying the nature of the ligand L . Thanks to the pronounced π-extended structure of the ligands and the heavy atom effect provided by the osmium center, these complexes exhibit a high absorption in the near-infrared (NIR) region (up to 740 nm), unlike related ruthenium complexes. This led to a promising phototoxicity in vitro against cancer cells cultured as 2D cell layers but also in multicellular tumor spheroids upon irradiation at 740 nm. The complex [Os(4,7-diphenyl-1,10-phenanthroline)₂(2,2′-bipyridine)]²⁺ was found to be the most efficient against various cancer cell lines, with high phototoxicity indexes. Experiments on CT26 tumor-bearing BALB/c mice also indicate that the Os^II complexes could significantly reduce tumor growth following 740 nm laser irradiation. The high phototoxicity in the biological window of this structurally simple complex makes it a promising photosensitizer for cancer treatment.     

Synthetic Strategies for the Selective Functionalization of Carbon Nanodots Allow Optically Communicating Suprastructures

The surface of Carbon Nanodots (CNDs) stands as a rich chemical platform, able to regulate the interactions between particles and external species. Performing selective functionalization of these nanoscale entities is of practical importance, however, it still represents a considerable challenge. In this work, we exploited the organic chemistry toolbox to install target functionalities on the CND surface, while monitoring the chemical changes on the material's outer shell through nuclear magnetic resonance spectroscopy. Following this, we investigated the use of click chemistry to covalently connect CNDs of different nature en-route towards covalent suprastructures with unprecedent molecular control. The different photophysical properties of the connected particles allowed their optical communication in the excited state. This work paves the way for the development of selective and addressable CND building blocks which can act as modular nanoscale synthons that mirror the long-established reactivity of molecular organic synthesis.     

A DNA Origami-Based Gene Editing System for Efficient Gene Therapy in Vivo

DNA nanostructures have played an important role in the development of novel drug delivery systems. Herein, we report a DNA origami-based CRISPR/Cas9 gene editing system for efficient gene therapy in vivo. In our design, a PAM-rich region precisely organized on the surface of DNA origami can easily recruit and load sgRNA/Cas9 complex by PAM-guided assembly and pre-designed DNA/RNA hybridization. After loading the sgRNA/Cas9 complex, the DNA origami can be further rolled up by the locking strands with a disulfide bond. With the incorporation of DNA aptamer and influenza hemagglutinin (HA) peptide, the cargo-loaded DNA origami can realize the targeted delivery and effective endosomal escape. After reduction by GSH, the opened DNA origami can release the sgRNA/Cas9 complex by RNase H cleavage to achieve a pronounced gene editing of a tumor-associated gene for gene therapy in vivo. This rationally developed DNA origami-based gene editing system presents a new avenue for the development of gene therapy.     

A DNA Origami-based Bactericide for Efficient Healing of Infected Wounds

Bacteria infection is a significant obstacle in the clinical treatment of exposed wounds facing widespread pathogens. Herein, we report a DNA origami-based bactericide for efficient anti-infection therapy of infected wounds in vivo. In our design, abundant DNAzymes (G4/hemin) can be precisely organized on the DNA origami for controllable generation of reactive oxygen species (ROS) to break bacterial membranes. After the destruction of the membrane, broad-spectrum antibiotic levofloxacin (LEV, loaded in the DNA origami through interaction with DNA duplex) can be easily delivered into the bacteria for successful sterilization. With the incorporation of DNA aptamer targeting bacterial peptidoglycan, the DNA origami-based bactericide can achieve targeted and combined antibacterial therapy for efficiently promoting the healing of infected wounds. This tailored DNA origami-based nanoplatform provides a new strategy for the treatment of infectious diseases in vivo.     

A New Calibration Method for the Gel Permeation Chromatographic Fractionation of Polymers

A model for the mechanism of the Gel permeation chromatographic separation of a polymer and a new calibration method have been developed, based on the exclusion of the polymer from the pores of the packing material. We propose that the calibration curve a plot of log (1—√K) versus log (molecular weight), where K is the elution volume coefficient, is close to linear over a K range of 0.15–0.85. We compare our procedure with that of Haller for various sets of data. Our procedure is generally better with lower standard deviations. When extrapolated, it gives a critical permeation size characteristic of the glass column packings.     

微乳凝胶中小分子传质研究

微乳凝胶中小分子传质研究对于拓宽胶束酶学研究内涵、加速酶在生物合成与转化领域中的应用、研制高性能生物传感器等具有重要理论意义和潜在应用价值.以微乳液中二价金属离子与紫脲酸胺之间的配位反应为指示反应,采用分光光度技术,研究了金属离子在由阳离子表面活性剂十六烷基三甲基溴化胺构建的微乳凝胶中的传质问题.结果表明,在由含紫脲酸胺微乳液及含金属离子微乳凝胶构成的体系中,金属离子在微乳凝胶中的传质是金属离子与紫脲酸胺配位反应的限速步骤.为进一步证实上述结论,还对影响金属离子在微乳凝胶中传质的各种因素(如微乳液中水与表面活性剂的摩尔比值、分散相中甘油与水的配比等)进行了研究,结果也证实了上述结论.     

Permeation liquid membrane for trace metal speciation in natural waters. Transport of liposoluble Cu(II) complexes

In this paper, the transport of Cu(II) in the presence of lipophilic Cu(II) organic complexes through permeation liquid membranes (PLMs) have been investigated. In natural waters, small organic compounds, which form liposoluble neutral complexes with Cu(II), are potentially toxic and bioavailable. Hence, to understand the role of liposoluble Cu(II) complexes in natural waters, four organic ligands: phthalic acid, bipyridyl, pyrocatechol and hydroxyquinoline, which form uncharged or lipophilic Cu(II) complexes, were tested. The results showed that the transport of lipophilic Cu(II) complexes through PLM depends on the lipophilicity of the complex. Applications of PLMs in natural waters are presented.     

Epitope Imprinting of Phospholipids by Oriented Assembly at the Oil/Water Interface for the Selective Recognition of Plasma Membranes

Phospholipids, as fundamental building blocks of the cell membrane, play important roles for molecule transportation, cell recognition, etc. However, due to the structural diversity and amphipathic nature, there are few methods for the specific recognition of lipids as compared to other biomolecules such as proteins and glycans. Herein, we developed a molecular imprinting strategy for controllable imprinting toward the polar head of phospholipid exposed on the surface of cellular membranes for recognition. Phosphatidylserine, as unique lipid on the outer membrane leaflet of exosome and also hallmark for cell apoptosis, was imprinted with the developed method. The phosphatidylserine imprinted materials showed high efficiency and specific targeting capability not only for apoptotic cell imaging but also for the isolation of exosomes. Collectively, the synthesized molecularly imprinted materials have great potential for selective plasma membrane recognition for targeted drug delivery and biomarker discovery.     

Supramolecular Enhancement of Electrochemical Nitrate Reduction Catalyzed by Cobalt Porphyrin Organic Cages for Ammonia Electrosynthesis in Water**

The electrochemical nitrate (NO₃⁻) reduction reaction (NO₃RR) to ammonia (NH₃) represents a sustainable approach for denitrification to balance global nitrogen cycles and an alternative to traditional thermal Haber-Bosch processes. Here, we present a supramolecular strategy for promoting NH₃ production in water from NO₃RR by integrating two-dimensional (2D) molecular cobalt porphyrin ( CoTPP ) units into a three-dimensional (3D) porous organic cage architecture. The porphyrin box CoPB-C8 enhances electrochemical active site exposure, facilitates substrate–catalyst interactions, and improves catalyst stability, leading to turnover numbers and frequencies for NH₃ production exceeding 200,000 and 56 s⁻¹, respectively. These values represent a 15-fold increase in NO₃RR activity and 200-mV improvement in overpotential for the 3D CoPB-C8 box structure compared to its 2D CoTPP counterpart. Synthetic tuning of peripheral alkyl substituents highlights the importance of supramolecular porosity and cavity size on electrochemical NO₃RR activity. These findings establish the incorporation of 2D molecular units into 3D confined space microenvironments as an effective supramolecular design strategy for enhancing electrocatalysis.