Simultaneous Formation of a Foldamer and a Self-Replicator by Out-of-Equilibrium Dynamic Covalent Chemistry.

Systems chemistry has emerged as a useful paradigm to access structures and phenomena typically exhibited by living systems, including complex molecular systems such as self-replicators and foldamers. As we progress further toward the noncovalent synthesis of life-like systems, and eventually life itself, it is necessary to gain control over assembly pathways. Dissipative chemical fueling has enabled access to stable populations of (self-assembled) structures that would normally form only transiently.

An Optical Probe for Real-Time Monitoring of Self-Replicator Emergence and Distinguishing between Replicators.

Self-replicating systems play an important role in research on the synthesis and origin of life. Monitoring of these systems has mostly relied on techniques such as NMR or chromatography, which are limited in throughput and demanding when monitoring replication in real time. To circumvent these problems, we now developed a pattern-generating fluorescent molecular probe (an ID-probe) capable of discriminating replicators of different chemical composition and monitoring the process of replicator formation in real time, giving distinct signatures for starting materials, intermediates, and final products.

Assessing changes in the expression levels of cell surface proteins with a turn-on fluorescent molecular probe.

Tri-nitrilotriacetic acid (NTA)-based fluorescent probes were developed and used to image His-tagged-labelled outer membrane protein C (His-OmpC) in live Escherichia coli. One of these probes was designed to light up upon binding, which provided the means to assess changes in the His-OmpC expression levels by taking a simple fluorescence spectrum.

A Metallosupramolecular Coordination Polymer for the 'Turn-on' Fluorescence Detection of Hydrogen Sulfide.

probe for the efficient detection of hydrogen sulfide in aqueous medium is reported. The investigated coumarine-based derivative forms spherical nanoparticles in aqueous media. In presence of Pd, a metallosupramolecular coordination polymer is formed, which is accompanied by quenching of the coumarin emission at 390 nm.

Switching the recognition ability of a photoswitchable receptor towards phosphorylated anions.

An azobenzene based photoswitchable macrocyclic receptor displays different binding affinities in its E and Z forms towards various phosphorylated coenzymes under physiological conditions with remarkable selectivity for ATP in the E-form and selectivity towards GTP in the photoisomerized Z-form. Linear discriminant analysis clearly separated the analytes using the E-form. An application of this method enabled monitoring the progress of enzymatic phosphorylation using a tyrosine kinase enzyme.

Multi-Stimuli-Responsive Supramolecular Polymers Based on Noncovalent and Dynamic Covalent Bonds.

Several modes of supramolecular assembly relying on noncovalent as well as dynamic covalent interactions were combined in a single molecule. The supramolecular self-assembly of can be controlled by three stimuli, namely light, pH, and addition of metal ions, in both organic and aqueous media. The multi-stimuli-responsive nature of was used successfully for the controlled encapsulation and on-demand release of hydrophobic molecules, such as dyes and drugs.

Diverse Properties of Guanidiniocarbonyl Pyrrole-Based Molecules: Artificial Analogues of Arginine.

The guanidinium moiety, which is present in active sites of many enzymes, plays an important role in the binding of anionic substrates. In addition, it was also found to be an excellent binding motif for supramolecular chemistry. Inspired by Nature, scientists have developed artificial receptors containing guanidinium scaffolds that bind to a variety of oxoanions through hydrogen bonding and charge pairing interactions.

Analyzing Amyloid Beta Aggregates with a Combinatorial Fluorescent Molecular Sensor.

Different amyloid beta (Aβ) aggregates can be discriminated by a combinatorial fluorescent molecular sensor. The unique optical fingerprints generated by the unimolecular analytical device provide a simple means to differentiate among aggregates generated from different alloforms or through distinct pathways. The sensor has also been used to track dynamic changes that occur in Aβ aggregation states, which result from the formation of low molecular weight oligomers, high molecular weight oligomers, protofibrils, and fibrils.

Photoreversible assembly-disassembly of a polymeric structure by using an azobenzene photoswitch and Al3+ ions.

A nonmacrocyclic azobenzene-based photochromic receptor in its E isomer forms an extended polymeric assembly with Al(3+) ions. Exposure of the E form to UV light at λ = 366 nm causes a disassembly of the polymeric structure due to the change in the molecular geometry of the ligand. The linear polymeric structure was regenerated on exposure to visible light.

A highly selective chemodosimeter for fast detection and intracellular imaging of Hg2+ ions based on a dithiocarbamate-isothiocyanate conversion in aqueous ethanol.

A new naphthalene diimide-dithiocarbamate based fluorescence probe was synthesized and its fluorogenic behavior towards various metal ions was studied. Upon addition of various metal ions, the probe afforded an irreversible change only with Hg(2+) ions in aqueous-ethanol media (4 : 1 v/v) with a fourfold enhancement of the fluorescence (Φ = 0.03 → 0.

Altered selectivity of a dipicolylamine based metal ion receptor.

2,2-Dipicolylamine (DPA) based receptors detect Zn(2+) with high fidelity. A fluorescent sensor with thiocarbamate-linked DPA turns it into a highly selective module for Ag(+) with up to ~7-fold enhancement of fluorescence. The sensor exhibits a double ratiometric behavior.

Histidine based fluorescence sensor detects Hg2+ in solution, paper strips, and in cells.

A chemosensor having a bipodal thiocarbamate scaffold attached to histidine moieties senses Hg(2+) with a remarkable selectivity. The binding results in a 50 nm blue shift in the fluorescence spectra and a 19-fold enhancement of the fluorescence quantum yield of the ligand. In addition to the detection of Hg(2+) visually under UV light in solution, the chemosensor was used for fabrication of paper strips that detected Hg(2+) in aqueous samples.

Pharmacy drug error awareness program.

Medication errors are a major concern in hospital pharmacy practice. The prevention of medication errors involves mainly the departments of pharmacy and nursing. Though there are many safeguards used to prevent medication errors, they still occur, posing potential harm to patients.