Pb-Selective Nanoemulsion-Integrated Single-Entity Electrochemistry for Ultrasensitive Sensing of Blood Lead.

Unequivocally, Pb as a harmful substance damaging children's brain and nerve systems, thereby causing behavior and learning disabilities, should be detected much lower than the elevated blood lead for children, 240 nM, endorsed by US CDC considering the unknown neurotoxic effects, yet the ultralow detection limit up to sub-ppb level remains a challenge due to the intrinsically insufficient sensitivity in the current analytical techniques. Here, we present nanoemulsion (NE)-integrated single-entity electrochemistry (NI-SEE) toward ultrasensitive sensing of blood lead using Pb-ion-selective ionophores inside a NE, i.e.

Bacterial multispecies interaction mechanisms dictate biogeographic arrangement between the oral commensals and .

As the microbiome era matures, the need for mechanistic interaction data between species is crucial to understand how stable microbiomes are preserved, especially in healthy conditions where the microbiota could help resist opportunistic or exogenous pathogens. Here we reveal multiple mechanisms of interaction between two commensals that dictate their biogeographic relationship to each other in previously described structures in human supragingival plaque. Using a novel variation for chemical detection, we observed metabolite exchange between individual bacterial cells in real time validating the ability of these organisms to carry out metabolic crossfeeding at distal and temporal scales observed .

Mechanistic Assessment of Metabolic Interaction between Single Oral Commensal Cells by Scanning Electrochemical Microscopy.

The human oral microbiome heavily influences the status of oral and systemic diseases through different microbial compositions and complex signaling between microbes. Recent evidence suggests that investigation of interactions between oral microbes can be utilized to understand how stable communities are maintained and how they may preserve health. Herein, we investigate two highly abundant species in the human supragingival plaque, and , to elucidate their real-time chemical communication in commensal harmony.

Nanoscale Carbonate Ion-Selective Amperometric/Voltammetric Probes Based on Ion-Ionophore Recognition at the Organic/Water Interface: Hidden Pieces of the Puzzle in the Nanoscale Phase.

Here, we report on the successful demonstration and application of carbonate (CO) ion-selective amperometric/voltammetric nanoprobes based on facilitated ion transfer (IT) at the nanoscale interface between two immiscible electrolyte solutions. This electrochemical study reveals critical factors to govern CO-selective nanoprobes using broadly available Simon-type ionophores forming a covalent bond with CO, i.e.

Lewis-Acid-Catalyzed Decarboxylative Annulation of 2-Aminoindole-3-Carboxylate with Ynals Involving [3 + 2] Spirocycloaddition and 2,3-Aza Migration.

2-Aminoindole-3-carboxylates undergo a Lewis-acid-catalyzed decarboxylative annulation with ynals to afford dihydrochromeno-fused δ-carbolines through a 2,3-aza migration, via a spirocyclic intermediate generated from an initial [3 + 2] spirocycloaddition. Brønsted acid interference changes the path from a [3 + 2] to a [4 + 2] addition. 2-Aminoindoles without an ester functional group at C3 underwent a different condensation, followed by hetero-Diels-Alder reaction to generate chromeno-fused α-carbolines.

Single-Entity Electrochemistry of Nanoemulsion: The Nanostructural Effect on Its Electrochemical Behavior.

New electrochemical approaches have been applied to investigate nanoemulsions (NEs) for their nanostructures and the relevant electrochemical activity by single-entity electrochemistry (SEE). Herein, we make highly monodisperse NEs with ∼40 nm diameter, composed of biocompatible surfactants, castor oil as plasticizers, and ion exchangers. Dynamic light scattering (DLS) measurements with periodically varying surfactant to oil ratios provide us with a structural implication about uneven distributions of incorporating components inside NEs.

Kinetics of Antimicrobial Drug Ion Transfer at a Water/Oil Interface Studied by Nanopipet Voltammetry.

Effective delivery and accumulation of antimicrobial agents into the microbial organism is essential for the treatment of bacterial infections. Transports of hydrophilic drug molecules, however, encounter a robust barrier of hydrophobic double membrane cell envelope, thus, leading to drug-resistance in Gram-negative bacteria. Accordingly, a deeper understanding about a transit of charged molecules through a bacterial membrane is needed to remediate the antibacterial resistance.

Nickel Catalyzed syn-Selective Aryl Nickelation and Cyclization of Aldehyde/Enone-Tethered Terminal Alkynes with Arylboronic Acids.

A syn-arylative nickelation followed by nucleophilic syn-selective cyclization of o-propargyloxy benzaldehydes is achieved toward the synthesis of chromanol skeletons with alkenyl substitution at C3. The capture of the intermediate vinyl nickel in its cis geometry is done also with a Michael acceptor to synthesize 4-alkylated derivatives. This protocol is equally applicable to o-propargylamino benzaldehydes to access 3,4-disubstituted tetrahydro-hydroquinolines.

Novel indole and triazole based hybrid molecules exhibit potent anti-adipogenic and antidyslipidemic activity by activating Wnt3a/β-catenin pathway.

Obesity and dyslipidemia is the two facet of metabolic syndrome, which needs further attention. Recent studies indicate triazole and indole derivatives have remarkable anti-obesity/antidyslipidemic activity. To harness the above-mentioned potential, a series of novel triazole clubbed indole derivatives were prepared using click chemistry and evaluated for anti-adipogenic activity.

Ag-Catalyzed Intramolecular Sequential Vicinal Diamination of Alkynes with Isocyanates: Synthesis of Fused Indole-Cyclic Urea Derivatives.

A formal intramolecular vicinal 1,2-diamination of alkynes is achieved for the synthesis of indole-cyclic urea fused derivatives through a double cyclization process from readily available aminophenyl propargyl alcohols. This sequential triple C-N bond construction event was possible using isocyanate as urea precursor and Ag(I) catalyst as alkyne activating agent. Control experiments reveal that the cyclization, followed by 1,3-allylic amino dehydroxylation, is preceded by urea formation.

Synthesis of Substituted Furan/Pyrrole-3-carboxamides through a Tandem Nucleopalladation and Isocyanate Insertion.

Access to furanyl- and pyrrolyl-3-carboxamides from readily available 3-alkyne-1,2-diols and 1-amino-3-alkyn-2-ols using isocyanate as amido surrogate is demonstrated. The approach constitutes a successful unprecedented combination of heteropalladation and isocyanate insertion, a new avenue for novel amide bond constructions. The mechanism likely involves a 6-membered oxaaminopalladacycle as the key intermediate.

BF3·OEt2-mediated syn-selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z-β-aryl-α,β-unsaturated esters.

Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.

Iodo Meyer-Schuster rearrangement of 3-alkoxy-2-yn-1-ols for β-mono (exclusively Z-selective)-/disubstituted α-iodo-α,β-unsaturated esters.

We herein present the iodo Meyer-Schuster rearrangement of 3-alkoxypropargyl alcohols for α-iodo-α,β-unsaturated esters using iodine or NIS in dichloromethane at ambient temperature. Substrates prepared from both aldehydes and ketones are found to be equally good feedstock for the reaction to produce β-mono- and -disubstituted products. Irrespective of the substitution, substrates prepared from aldehydes gave Z-isomers exclusively.

Synthesis of substituted 3-iodocoumarins and 3-iodobutenolides via electrophilic iodocyclization of ethoxyalkyne diols.

A convenient and general synthesis of various 4-substituted 3-iodocoumarins and 4,5-disubstituted 3-iodobutenolides is described via an exclusive 6-endo-dig iodocyclization of 3-ethoxy-1-(2-alkoxyphenyl)-2-yn-1-ols and 5-endo-dig iodocyclization of 1-alkoxy-4-ethoxy-3-yn-1,2-diols, respectively. The reaction is carried out under very mild conditions using I2 in CH2Cl2 or toluene at room temperature. Oxygens in OMe and OMOM groups were used as efficient nucleophiles for this intramolecular cyclization to obtain the products in good to excellent yields.