Ultrasound Promoted Step-Growth Polymerization and Polymer Crosslinking Via Copper Catalyzed Azide-Alkyne "Click" Reaction.

Mechano-activated chemistry is a powerful tool for remodeling of synthetic polymeric materials, however, few reactions are currently available. Here we show that using piezochemical reduction of a Cu -based pre-catalyst, a step-growth polymerization occurs via the copper catalyzed azide-alkyne cycloaddition (CuAAC) reaction to form a linear polytriazole. Furthermore, we show that a linear polymer can be crosslinked mechanochemically using the same chemistry to form a solid organogel.

Cooperative CO Absorption Isotherms from a Bifunctional Guanidine and Bifunctional Alcohol.

Designing new liquids for CO absorption is a challenge in CO removal. Here, achieving low regeneration energies while keeping high selectivity and large capacity are current challenges. Recent cooperative metal-organic frameworks have shown the potential to address many of these challenges.

Design, Synthesis, and Characterization of Small-Molecule Reagents That Cooperatively Provide Dual Readouts for Triaging and, When Necessary, Quantifying Point-of-Need Enzyme Assays.

A newly designed small molecule reagent provides both qualitative and quantitative readouts in assays that detect enzyme biomarkers. The qualitative readout enables rapid triaging of samples so that only samples that contain relevant concentrations of the target analyte must be quantified. The reagent is accessible in essentially three steps and 34% overall yield, is stable as a solid when heated to 44 °C for >1 month, and does not produce background signal when used in an assay.

Stimuli-Responsive Polymer Film that Autonomously Translates a Molecular Detection Event into a Macroscopic Change in Its Optical Properties via a Continuous, Thiol-Mediated Self-Propagating Reaction.

This Communication describes a chemically responsive polymer film that is capable of detecting low levels of a specific applied molecular signal (thiol) and subsequently initiating a self-propagating reaction within the material that converts the nonfluorescent film into a globally fluorescent material. We illustrate that the intensity of the resulting fluorescent material is independent of the quantity of the applied thiol, whereas the rate to reach the maximum level of signal is directly proportional to the quantity of the signal. In contrast, a control film, which lacks functionality for mediating the self-propagating reaction, provides a maximum change in fluorescence that is directly proportional to the quantity of the applied thiol.

Rapid, On-Command Debonding of Stimuli-Responsive Cross-Linked Adhesives by Continuous, Sequential Quinone Methide Elimination Reactions.

Adhesives that selectively debond from a surface by stimuli-induced head-to-tail continuous depolymerization of poly(benzyl ether) macro-cross-linkers within a poly(norbornene) matrix are described. Continuous head-to-tail depolymerization provides faster rates of response than can be achieved using a small-molecule cross-linker, as well as responses to lower stimulus concentrations. Shear-stress values for glass held together by the adhesive reach 0.

Surface-accessible detection units in self-immolative polymers enable translation of selective molecular detection events into amplified responses in macroscopic, solid-state plastics.

This Communication describes a strategy for incorporating detection units onto each repeating unit of self-immolative CDr polymers. This strategy enables macroscopic plastics to respond quickly to specific applied molecular signals that react with the plastic at the solid-liquid interface between the plastic and surrounding fluid. The response is a signal-induced depolymerization reaction that is continuous and complete from the site of the reacted detection unit to the end of the polymer.

Reagents and assay strategies for quantifying active enzyme analytes using a personal glucose meter.

This communication describes small molecule reagents and a rapid single-step assay for quantifying nanomolar levels of active enzyme analytes using a personal glucose meter.

Phase switching to enable highly selective activity-based assays.

Traditional activity-based (or reaction-based) detection schemes rely on homogeneous reactions between an analyte and a substrate to provide a signal that is proportional to the concentration of the analyte. Selectivity in these assays is governed primarily by the ability of the desired analyte to react faster than other analytes with the substrate. In this Article, we describe a conceptually different approach toward activity-based detection whereby a soluble analyte is converted intentionally into a heterogeneous catalyst.

Using smell to triage samples in point-of-care assays.

Smell of success: Reagent 1 provides the dual readouts of odor (ethanethiol) and fluorescence (derivative of 7-hydroxycoumarin) and can be used in down-selection assays based on smell and quantitative fluorescence assays of the samples that give a positive result. An important feature of 1 is the matched sensitivity of the two outputs. This reagent is designed for use in resource-limited settings and is demonstrated in assays that detect enzymes.

Design of small molecule reagents that enable signal amplification via an autocatalytic, base-mediated cascade elimination reaction.

This Communication describes three small molecule reagents that amplify the signal for a detection event via an autocatalytic reaction. Two signals are obtained from each reagent: (i) the dibenzofulvene chromophore and (ii) piperidine, which can be visualized using a pH indicator dye. The reagents are demonstrated in a model assay for palladium.